title: Fermentation of vitamin K2 (menaquinone-7): Development of an optimal fermentation process to selectively enhance the production of the biologically significant all-trans isomer

authors: Lal, Neha Natasha

subjects: Fermentation

abstract: Vitamin K is a lipid-soluble vitamin first discovered in 1929 by the Danish nutritional biochemist Carl Peter Henrick Dam as an antihaemorrhagic factor capable of correcting dietary-induced bleeding disorders in chicks. The vitamin K family encompasses a series of structurally related compounds, namely vitamin K1 (phylloquinone), vitamin K2 (menaquinones), and vitamin K3 (menadione), which share a common 2-methyl-1,4-naphthoquinone moiety but differ in the structure of a lateral isoprenoid chain at the 3-position. Despite their structural similarities, all K vitamers have different pharmacokinetic properties attributable to the length and degree of saturation of their isoprenoid side chain.

All vitamin K isoforms are involved in the activation of hepatic and extrahepatic vitamin K-dependent proteins (VKDPs) and play a central role in blood coagulation and haemostasis. Additionally, it has been established that the potential health benefits of vitamin K are far more diverse. In particular, menaquinones (MKs) offer more significant health gains than phylloquinone (PK) and have been associated with the prevention of osteoporosis and cardiovascular diseases (CVDs) and decreasing the risk of and improving the outcomes associated with several illnesses and health conditions, including cancer, neurological diseases, type 2 diabetes mellitus, chronic kidney disease, immune disorders, obesity, and coronavirus disease 2019 (COVID-19). 

Of the various MKs, menaquinone-7 (MK-7) has superior bioavailability due to its long plasma half-life. Thus, it is considered the most notable form of vitamin K2 and has the greatest efficacy with respect to extrahepatic biological functions. However, MK-7 exists at low concentrations in limited foods, especially those with universal appeal. This has incentivised the development of MK-7 dietary supplements and functional food products to complement natural sources and satisfy the daily intake requirements of this essential vitamin. 

Recently, it has been recognised that MK-7 exists as geometric isomers, comprising the bioactive all-trans isomer and various cis forms of the compound, which lack or have considerably compromised biological significance. This is a salient aspect worthy of attention, as the effectiveness of MK-7 nutritional supplements is primarily determined by the content of all-trans MK-7, and all other isomers of the vitamin are essentially impurities that lack therapeutic value.

MK-7 can be produced synthetically from chemical reaction methods or naturally from bacterial fermentation. The latest market trend promoting natural and organic alternatives over synthetic products has rendered natural fermentation-based synthesis more favourable from a consumer’s perspective. Furthermore, microbial production is a more sustainable approach for the large-scale synthesis of MK-7; hence, natural fermentation techniques can satisfy both the market demand and sustainable development goals. 

The MK-7 isomer composition of the final product is influenced by many factors, predominantly the methods used for its production and the purification of the post-reaction mixture, as well as exposure to certain environmental factors and storage conditions. It is important to appreciate that while studies analysing the isomer profile of MK-7 dietary supplement preparations of various origins have been carried out, the isomer composition resulting from fermentation processes has not been elucidated. 

In light of the fact that only all-trans MK-7 sustains biological activity and fermentation-based synthesis is superior from both the viewpoint of consumers and the environment, the MK-7 isomer profile attained from fermentation warrants further investigation. Therefore, the fundamental aim of this research was to evaluate the MK-7 isomer composition resulting from fermentation processes employing different synthesis conditions to explicate the optimal fermentation method for the production of the biologically significant all-trans form of the vitamin. A holistic approach was adopted to systematically follow a typical fermentation process from its foundational stages to the final fermented product while considering the MK-7 isomer profile obtained from fermentation under various conditions and the bioactivity and therapeutic value of fermented MK-7 consumer end products. Accordingly, key aspects of upstream and downstream fermentation were explored, along with nanobiotechnological approaches, to potentially address the major challenges accompanying the fermentation and downstream processing of MK-7. The isomer composition and stability of all-trans MK-7 resulting from exposure to possible conditions and environmental factors encountered during the manufacture, transportation, and storage of fermented bioactive MK-7 goods available on the market were also assessed. 

The selection of nutrients, particularly carbon, nitrogen, and salt sources, and their respective concentrations in the fermentation media are a central aspect of any fermentation process, as they influence microbial growth and metabolism and, ultimately, the process productivity and product yield. Thus, the first step was to consider the impact of the media composition on MK-7 isomer production and ascertain the optimum media combination to favour the synthesis of all-trans MK-7. Several nutrient sources were screened, and the concentration of the effective media components was optimised to obtain the ideal fermentation media, which contained 1% (w/v) glucose, 2% (w/v) yeast extract, 2% (w/v) soy peptone, 2% (w/v) tryptone, and 0.1% (w/v) calcium chloride (CaCl2). The optimal fermentation media resulted in an all-trans isomer concentration of 36.37 mg/L and a cis isomer concentration of 1.23 mg/L. It was also established that only a single cis isomer is obtained from fermentation under the investigated conditions. Moreover, different concentrations of the cis isomer were achieved when the selection and concentration of nutrients constituting the fermentation media were varied, implying that the media composition is instrumental in determining the nature of the extracellular environment in the fermentation broth, and this likely influences the extent to which all-trans MK-7 isomerises to the cis form.

Various fermentation parameters and operating conditions also play an indispensable part in fermentation processes, as they contribute to the microbial growth environment and, hence, impact product formation and the efficacy of the fermentation system. Consequently, the subsequent focus was to explore the effect of crucial fermentation parameters, specifically the inoculum size, fermentation temperature, agitation speed, and length of fermentation, on the MK-7 isomer profile. These factors were optimised to enhance the synthesis of the biologically important all-trans isomer and minimise the concentration of cis MK-7 while using the previously developed fermentation media. The optimum fermentation conditions consisted of an inoculum size of 2% (v/v), a fermentation temperature of 40 °C, an agitation speed of 200 rpm, and a fermentation period of 7 days and enabled an all-trans and cis isomer concentration of 53.29 mg/L and 1.22 mg/L, respectively. An approximately 46.5% greater all-trans MK-7 concentration was attained from fermentation utilising the optimal media, inoculum size, temperature, agitation speed, and duration compared to fermentation with only the optimum media composition, which emphasises the pivotal role of the fermentation environment in regulating the production of the desired isomer.

Although fermentation is the preferred method for MK-7 synthesis, its low yield and large number of downstream processing steps increase production expenses and the cost of the final product. The high price of fermented MK-7 supplements reduces their widespread accessibility. While optimisation of various aspects of the fermentation process, such as the fermentation format, nutrient selection and media composition, and value of key fermentation parameters and operating conditions, serves to enhance the production and yield of MK-7, it offers little opportunity to refine the fermentation system through process intensification. Therefore, there is a need for innovative approaches to not only boost the process yield but also streamline the overall fermentation procedure by decreasing the complexity and number of unit operations involved in the downstream processing of the vitamin. It is also essential to ensure that all-trans MK-7 is produced almost exclusively or in the most significant proportion during fermentation. In this regard, bacterial cell immobilisation with biocompatible magnetic iron oxide nanoparticles (IONs) was investigated to assess their influence on the MK-7 isomer profile obtained from fermentation. Three types of IONs, including one uncoated (naked) and two coated (amine-functionalised) IONs, were synthesised using the co-precipitation method and characterised using several techniques, and their effect on microbial growth and the production and yield of MK-7 isomers was considered. Naked IONs were initially examined, and the results were compared with the findings for the 3-aminopropyltriethoxysilane (APTES)- and L-lysine (L-Lys)-coated IONs (IONs@APTES and L-Lys@IONs). The optimum concentration of naked IONs was 300 μg/mL, and it improved the process output and resulted in an all-trans MK-7 concentration of 28.78 mg/L and a 1.6-fold greater all-trans isomer yield relative to the control. In comparison to the naked IONs, the amine-functionalised IONs had superior properties and provided more positive outcomes. The optimal IONs@APTES and L-Lys@IONs concentrations were 300 μg/mL and 400 μg/mL, enabling a maximum all-trans MK-7 concentration of 41.93 mg/L and 32.08 mg/L, respectively. In addition, the yield of the biologically effective isomer compared to the control increased by 3.1-fold for the IONs@APTES and 2.1-fold for the L-Lys@IONs. Of all three forms of IONs that were explored, it was determined that 300 μg/mL of IONs@APTES was the most beneficial to enhance the all-trans isomer concentration and minimise the synthesis of cis MK-7. The magnetic nature of IONs also increases the scope for process intensification through magnetic separation technology, which has the potential to improve the productivity of MK-7 fermentation. 

It is of interest to note that the greatest all-trans MK-7 concentration obtained in the presence of IONs (41.93 mg/L) was less than that achieved in their absence when applying the same fermentation media and operating conditions as previous experiments (53.29 mg/L). This disparity can be attributed to the different fermentation volumes used in the two studies, as even the untreated (control) samples in the experiments involving IONs resulted in considerably lower concentrations of the all-trans isomer (less than 15 mg/L). All prior investigations were carried out on a small scale (6 mL), whereas the studies employing IONs required a slightly greater volume (approximately 20 mL) to accommodate the inclusion of IONs in the fermentation medium and the related measurements. It is apparent that even a small increase in the volume and, consequently, the scale of the fermentation process has a noticeable impact on the concentration of the target product. These observations highlight the central role of the fermentation volume in determining the concentration of all-trans MK-7 attained on a larger scale and present basic knowledge of likely challenges associated with the scale-up of fermentation processes targeting the production of the bioactive isomer.

It has been proposed that exposure to various environmental conditions influences the isomer composition of MK-7 products. Awareness of these factors and their impact on the proportion of MK-7 isomers is vital to preserve the content of the biologically significant all-trans isomer and prevent its transformation to cis MK-7 during the storage of fermented MK-7 supplements and fortified or functional foods. In this respect, the effect of short-term exposure to common environmental factors and storage conditions, such as light, atmospheric oxygen, and different temperatures, on the MK-7 isomer profile was considered to establish the optimum conditions to conserve the quantity of the all-trans isomer during the storage of fermented MK-7 preparations. It was ascertained that the vitamin is reasonably heat-stable but extremely light-sensitive. Long-term storage at a low temperature with minimal oxygen exposure in the absence of light resulted in a negligible change in the concentration of the all-trans isomer and was, thus, the optimal environment for the prolonged storage of fermented all-trans MK-7. These findings provide a deeper understanding of the impact of different environments on the stability of the biologically efficacious isomer and are a valuable step forward in establishing ideal storage conditions to maintain the concentration of all-trans MK-7 in fermented nutritional supplements.

Overall, this research presents novel insights into the MK-7 isomer profile achieved from fermentation in various contexts, a previously unexplored field, and has laid the foundation for future studies. Although it is desirable to exclusively produce the bioactive isomer from fermentation, the collective experimental findings have revealed that obtaining small quantities of the cis isomer alongside all-trans MK-7 is largely unavoidable under the circumstances considered. However, it is possible to maximise the concentration of the all-trans isomer and minimise the amount of the biologically insignificant isomer, which is a reasonable compromise. Appreciation of the key factors that influence the MK-7 isomer composition resulting from fermentation will allow their manipulation to attain a more favourable MK-7 profile in the final preparation, which can be included in nutraceuticals, dietary supplements, and functional food products or used in purified form. Furthermore, the outcomes of this study have the potential to aid the development of an industrial fermentation process that specifically targets the production of the biologically active and therapeutically valuable all-trans MK-7 isomer. The prospect for process intensification through the innovative use of magnetic IONs will likely streamline the production system and decrease the related expenses. This will help reduce the price and increase the accessibility of fermented bioactive MK-7 supplements and fortified or functional foods. Moreover, a greater understanding of the environmental factors and storage conditions that affect the isomer composition of fermented MK-7 preparations is likely to improve the standard of MK-7 nutritional products by preserving the quantity of the all-trans isomer. The widespread availability and consumption of high-quality bioactive MK-7 products by a range of consumers are expected to raise the vitamin K status of individuals and decrease the risk and progression of several age-related disorders and diseases of global significance. This holds great promise for reducing the disease burden and alleviating the socioeconomic consequences of an ageing population.

text: Fermentation of vitamin K2 (menaquinone-7): Development of an optimal fermentation process to selectively enhance the production of the biologically significant all-trans isomer Vitamin K is a lipid-soluble vitamin first discovered in 1929 by the Danish nutritional biochemist Carl Peter Henrick Dam as an antihaemorrhagic factor capable of correcting dietary-induced bleeding disorders in chicks. The vitamin K family encompasses a series of structurally related compounds, namely vitamin K1 (phylloquinone), vitamin K2 (menaquinones), and vitamin K3 (menadione), which share a common 2-methyl-1,4-naphthoquinone moiety but differ in the structure of a lateral isoprenoid chain at the 3-position. Despite their structural similarities, all K vitamers have different pharmacokinetic properties attributable to the length and degree of saturation of their isoprenoid side chain.

All vitamin K isoforms are involved in the activation of hepatic and extrahepatic vitamin K-dependent proteins (VKDPs) and play a central role in blood coagulation and haemostasis. Additionally, it has been established that the potential health benefits of vitamin K are far more diverse. In particular, menaquinones (MKs) offer more significant health gains than phylloquinone (PK) and have been associated with the prevention of osteoporosis and cardiovascular diseases (CVDs) and decreasing the risk of and improving the outcomes associated with several illnesses and health conditions, including cancer, neurological diseases, type 2 diabetes mellitus, chronic kidney disease, immune disorders, obesity, and coronavirus disease 2019 (COVID-19). 

Of the various MKs, menaquinone-7 (MK-7) has superior bioavailability due to its long plasma half-life. Thus, it is considered the most notable form of vitamin K2 and has the greatest efficacy with respect to extrahepatic biological functions. However, MK-7 exists at low concentrations in limited foods, especially those with universal appeal. This has incentivised the development of MK-7 dietary supplements and functional food products to complement natural sources and satisfy the daily intake requirements of this essential vitamin. 

Recently, it has been recognised that MK-7 exists as geometric isomers, comprising the bioactive all-trans isomer and various cis forms of the compound, which lack or have considerably compromised biological significance. This is a salient aspect worthy of attention, as the effectiveness of MK-7 nutritional supplements is primarily determined by the content of all-trans MK-7, and all other isomers of the vitamin are essentially impurities that lack therapeutic value.

MK-7 can be produced synthetically from chemical reaction methods or naturally from bacterial fermentation. The latest market trend promoting natural and organic alternatives over synthetic products has rendered natural fermentation-based synthesis more favourable from a consumer’s perspective. Furthermore, microbial production is a more sustainable approach for the large-scale synthesis of MK-7; hence, natural fermentation techniques can satisfy both the market demand and sustainable development goals. 

The MK-7 isomer composition of the final product is influenced by many factors, predominantly the methods used for its production and the purification of the post-reaction mixture, as well as exposure to certain environmental factors and storage conditions. It is important to appreciate that while studies analysing the isomer profile of MK-7 dietary supplement preparations of various origins have been carried out, the isomer composition resulting from fermentation processes has not been elucidated. 

In light of the fact that only all-trans MK-7 sustains biological activity and fermentation-based synthesis is superior from both the viewpoint of consumers and the environment, the MK-7 isomer profile attained from fermentation warrants further investigation. Therefore, the fundamental aim of this research was to evaluate the MK-7 isomer composition resulting from fermentation processes employing different synthesis conditions to explicate the optimal fermentation method for the production of the biologically significant all-trans form of the vitamin. A holistic approach was adopted to systematically follow a typical fermentation process from its foundational stages to the final fermented product while considering the MK-7 isomer profile obtained from fermentation under various conditions and the bioactivity and therapeutic value of fermented MK-7 consumer end products. Accordingly, key aspects of upstream and downstream fermentation were explored, along with nanobiotechnological approaches, to potentially address the major challenges accompanying the fermentation and downstream processing of MK-7. The isomer composition and stability of all-trans MK-7 resulting from exposure to possible conditions and environmental factors encountered during the manufacture, transportation, and storage of fermented bioactive MK-7 goods available on the market were also assessed. 

The selection of nutrients, particularly carbon, nitrogen, and salt sources, and their respective concentrations in the fermentation media are a central aspect of any fermentation process, as they influence microbial growth and metabolism and, ultimately, the process productivity and product yield. Thus, the first step was to consider the impact of the media composition on MK-7 isomer production and ascertain the optimum media combination to favour the synthesis of all-trans MK-7. Several nutrient sources were screened, and the concentration of the effective media components was optimised to obtain the ideal fermentation media, which contained 1% (w/v) glucose, 2% (w/v) yeast extract, 2% (w/v) soy peptone, 2% (w/v) tryptone, and 0.1% (w/v) calcium chloride (CaCl2). The optimal fermentation media resulted in an all-trans isomer concentration of 36.37 mg/L and a cis isomer concentration of 1.23 mg/L. It was also established that only a single cis isomer is obtained from fermentation under the investigated conditions. Moreover, different concentrations of the cis isomer were achieved when the selection and concentration of nutrients constituting the fermentation media were varied, implying that the media composition is instrumental in determining the nature of the extracellular environment in the fermentation broth, and this likely influences the extent to which all-trans MK-7 isomerises to the cis form.

Various fermentation parameters and operating conditions also play an indispensable part in fermentation processes, as they contribute to the microbial growth environment and, hence, impact product formation and the efficacy of the fermentation system. Consequently, the subsequent focus was to explore the effect of crucial fermentation parameters, specifically the inoculum size, fermentation temperature, agitation speed, and length of fermentation, on the MK-7 isomer profile. These factors were optimised to enhance the synthesis of the biologically important all-trans isomer and minimise the concentration of cis MK-7 while using the previously developed fermentation media. The optimum fermentation conditions consisted of an inoculum size of 2% (v/v), a fermentation temperature of 40 °C, an agitation speed of 200 rpm, and a fermentation period of 7 days and enabled an all-trans and cis isomer concentration of 53.29 mg/L and 1.22 mg/L, respectively. An approximately 46.5% greater all-trans MK-7 concentration was attained from fermentation utilising the optimal media, inoculum size, temperature, agitation speed, and duration compared to fermentation with only the optimum media composition, which emphasises the pivotal role of the fermentation environment in regulating the production of the desired isomer.

Although fermentation is the preferred method for MK-7 synthesis, its low yield and large number of downstream processing steps increase production expenses and the cost of the final product. The high price of fermented MK-7 supplements reduces their widespread accessibility. While optimisation of various aspects of the fermentation process, such as the fermentation format, nutrient selection and media composition, and value of key fermentation parameters and operating conditions, serves to enhance the production and yield of MK-7, it offers little opportunity to refine the fermentation system through process intensification. Therefore, there is a need for innovative approaches to not only boost the process yield but also streamline the overall fermentation procedure by decreasing the complexity and number of unit operations involved in the downstream processing of the vitamin. It is also essential to ensure that all-trans MK-7 is produced almost exclusively or in the most significant proportion during fermentation. In this regard, bacterial cell immobilisation with biocompatible magnetic iron oxide nanoparticles (IONs) was investigated to assess their influence on the MK-7 isomer profile obtained from fermentation. Three types of IONs, including one uncoated (naked) and two coated (amine-functionalised) IONs, were synthesised using the co-precipitation method and characterised using several techniques, and their effect on microbial growth and the production and yield of MK-7 isomers was considered. Naked IONs were initially examined, and the results were compared with the findings for the 3-aminopropyltriethoxysilane (APTES)- and L-lysine (L-Lys)-coated IONs (IONs@APTES and L-Lys@IONs). The optimum concentration of naked IONs was 300 μg/mL, and it improved the process output and resulted in an all-trans MK-7 concentration of 28.78 mg/L and a 1.6-fold greater all-trans isomer yield relative to the control. In comparison to the naked IONs, the amine-functionalised IONs had superior properties and provided more positive outcomes. The optimal IONs@APTES and L-Lys@IONs concentrations were 300 μg/mL and 400 μg/mL, enabling a maximum all-trans MK-7 concentration of 41.93 mg/L and 32.08 mg/L, respectively. In addition, the yield of the biologically effective isomer compared to the control increased by 3.1-fold for the IONs@APTES and 2.1-fold for the L-Lys@IONs. Of all three forms of IONs that were explored, it was determined that 300 μg/mL of IONs@APTES was the most beneficial to enhance the all-trans isomer concentration and minimise the synthesis of cis MK-7. The magnetic nature of IONs also increases the scope for process intensification through magnetic separation technology, which has the potential to improve the productivity of MK-7 fermentation. 

It is of interest to note that the greatest all-trans MK-7 concentration obtained in the presence of IONs (41.93 mg/L) was less than that achieved in their absence when applying the same fermentation media and operating conditions as previous experiments (53.29 mg/L). This disparity can be attributed to the different fermentation volumes used in the two studies, as even the untreated (control) samples in the experiments involving IONs resulted in considerably lower concentrations of the all-trans isomer (less than 15 mg/L). All prior investigations were carried out on a small scale (6 mL), whereas the studies employing IONs required a slightly greater volume (approximately 20 mL) to accommodate the inclusion of IONs in the fermentation medium and the related measurements. It is apparent that even a small increase in the volume and, consequently, the scale of the fermentation process has a noticeable impact on the concentration of the target product. These observations highlight the central role of the fermentation volume in determining the concentration of all-trans MK-7 attained on a larger scale and present basic knowledge of likely challenges associated with the scale-up of fermentation processes targeting the production of the bioactive isomer.

It has been proposed that exposure to various environmental conditions influences the isomer composition of MK-7 products. Awareness of these factors and their impact on the proportion of MK-7 isomers is vital to preserve the content of the biologically significant all-trans isomer and prevent its transformation to cis MK-7 during the storage of fermented MK-7 supplements and fortified or functional foods. In this respect, the effect of short-term exposure to common environmental factors and storage conditions, such as light, atmospheric oxygen, and different temperatures, on the MK-7 isomer profile was considered to establish the optimum conditions to conserve the quantity of the all-trans isomer during the storage of fermented MK-7 preparations. It was ascertained that the vitamin is reasonably heat-stable but extremely light-sensitive. Long-term storage at a low temperature with minimal oxygen exposure in the absence of light resulted in a negligible change in the concentration of the all-trans isomer and was, thus, the optimal environment for the prolonged storage of fermented all-trans MK-7. These findings provide a deeper understanding of the impact of different environments on the stability of the biologically efficacious isomer and are a valuable step forward in establishing ideal storage conditions to maintain the concentration of all-trans MK-7 in fermented nutritional supplements.

Overall, this research presents novel insights into the MK-7 isomer profile achieved from fermentation in various contexts, a previously unexplored field, and has laid the foundation for future studies. Although it is desirable to exclusively produce the bioactive isomer from fermentation, the collective experimental findings have revealed that obtaining small quantities of the cis isomer alongside all-trans MK-7 is largely unavoidable under the circumstances considered. However, it is possible to maximise the concentration of the all-trans isomer and minimise the amount of the biologically insignificant isomer, which is a reasonable compromise. Appreciation of the key factors that influence the MK-7 isomer composition resulting from fermentation will allow their manipulation to attain a more favourable MK-7 profile in the final preparation, which can be included in nutraceuticals, dietary supplements, and functional food products or used in purified form. Furthermore, the outcomes of this study have the potential to aid the development of an industrial fermentation process that specifically targets the production of the biologically active and therapeutically valuable all-trans MK-7 isomer. The prospect for process intensification through the innovative use of magnetic IONs will likely streamline the production system and decrease the related expenses. This will help reduce the price and increase the accessibility of fermented bioactive MK-7 supplements and fortified or functional foods. Moreover, a greater understanding of the environmental factors and storage conditions that affect the isomer composition of fermented MK-7 preparations is likely to improve the standard of MK-7 nutritional products by preserving the quantity of the all-trans isomer. The widespread availability and consumption of high-quality bioactive MK-7 products by a range of consumers are expected to raise the vitamin K status of individuals and decrease the risk and progression of several age-related disorders and diseases of global significance. This holds great promise for reducing the disease burden and alleviating the socioeconomic consequences of an ageing population.

year: 2023

title: Restoring freshwater quality: an integrated environmental, economic and ecosystem services assessment of reducing nutrient loads to Lake Rotorua

authors: Mueller, Hannah

subjects: Water quality

abstract: The management of freshwater resources is a global concern as anthropogenic pressures on these resources have intensified. A decline in the quantity and quality of freshwater urgently requires concerted restoration actions to reverse the decline. Restoration of lakes is impacted by complex relationships of ecosystem responses to management actions, economic constraints, societal pressures and policy contexts. Research in this thesis was aimed at an integrated assessment covering these aspects to inform future lake restoration action. The overarching objective of this thesis is to evaluate ecological and economic aspects of lake restoration, assessing the economic importance of ecosystems through exploring the costs of restoring and managing them, and assessing the ecological effectiveness of restoration actions. A focus was the evaluation of ecosystem services provided by a lake and its catchment, and uses quantitative analysis to study lake management dynamics to analyse what impedes successful lake restoration.
	This research uses a case study of Lake Rotorua, central North Island, New Zealand. Like many lake ecosystems, this lake has been subject to pressures from human activity for decades, driving eutrophication and decline in ecosystem health. Land use has played a major role in nutrient enrichment of this lake. Restoration actions have been targeted at limiting nutrient loss from land, and reducing internal loading of the lake through engineering solutions. The aim of the research here was to analyse historical management responses and current management options alongside economic values of the lake and the catchment. The interdisciplinary assessment is aimed at connecting the lake to the catchment, as well as ecological to economic and policy assessments; such an integrated approach provides insight not only on the restoration of Lake Rotorua, but can also contribute to the management of lakes throughout New Zealand.
A main aim was to offer an integrated environmental, economic and policy assessment of the process of restoring water quality by reducing nutrient loads from the catchment alongside engineering options designed to reduce nutrients within the lake. The objectives for this thesis were to (1) explore a number of underlying drivers of lake management and the mechanisms for implementation of restoration initiatives, historically and in present times, (2) analyse ecosystem services and associated economic values of the lake ecosystem that are currently not valued by markets, and (3) evaluate cost-effectiveness of options to manage nutrient loads to the lake and internal loads through in-lake mitigation options, synthesising information on possible environmental outcomes and economic benefits for the lake and its catchment.
Several different methods were used to address these research objectives. To analyse the drivers of ecosystem degradation and resulting management initiatives, water quality data and research publications on Lake Rotorua were collected from 1922 to 2012. These data were categorised using the Drivers-Pressures-State-Impact-Response (DPSIR) model. Important management and environmental changes were used as independent variables in the year of their occurrence. Results of a Generalised Maximum Entropy (GME) regression, a specialised multinomial regression that is suitable for small datasets with a diverse range of variables (binary and continuous), showed that management was reactive, and policy responses (followed by regulatory interventions) often took effect only when ecosystem decline was already well advanced. There was also a disconnect between land use intensification and its role in driving water quality change, and long social lag times between the recognition of the environmental issue and a policy response delayed implementation of restoration actions.
To complement the historical study of lake restoration, the economic value of the lake and costs associated with degradation were evaluated to inform future management. Based on standard ecosystem services classification systems such as the Millennium Ecosystem Assessment in 2005, five different ecosystem services provided by the lake (habitat provision, food, nutrient processing, aesthetics, and recreation) were assessed. A range of direct and indirect valuation approaches, including existence value, hedonic pricing, and replacement cost, were used to assess the annual economic value of the lake ecosystem. A range of direct and indirect valuation concepts, including existence value, hedonic pricing and replacement cost, were used to assess the annual economic value of the lake ecosystem. A potential damage cost of the impacts of continued eutrophication was estimated as part of this economic assessment based on the current value of the lake and estimated reduction factors in ecosystem service provision and associated values.
To assess the effectiveness of options to reduce nutrient loads to the lake, a range of nutrient load scenarios was analysed for their effect on lake water quality using a hydrodynamic-ecological lake model (DYRESM-CAEDYM). Options needed to meet nutrient reductions as key component of a lake water quality target set by policy included mitigation on land, mitigation in the lake, and land use change. Different costs were attributed to each option, including lake and land mitigation costs. Values of different land use types and ecosystem services values of the catchment were included in the analysis. Costs and changes in values were determined for each scenario, to integrate an analysis of environmental effectiveness and costs of management options. Costs associated with these options were determined to illustrate the environmental effectiveness and potential costs of management options.
	Main findings of this thesis are that freshwater management is subject to response lags between the recognition of environmental decline and the restorative action undertaken to address this decline. These lags relate to the visibility of environmental problems in the public sphere, with action often only undertaken once effects such as lake weeds, low water clarity and possibly toxic algal blooms impact the public. Social lag times also exist as part of the general bureaucratic management process, and within scientific research to inform management. Lags mean that ecosystem degradation can be allowed to proceed until impacts, at times, become irreversible. This research found that a better integration of science and policy could inform management decision making by providing a holistic framework integrating ecological knowledge, pursuits of economic growth and societal constraints.
The ecosystem services value of Lake Rotorua based on the ecosystem services of food, habitat provision, nutrient processing, aesthetics and recreation was calculated to be $100-145 million per year. Ecosystem services provided by the catchment based on the current land use types were $176 million annually. A policy target for water quality was set for the lake. The ecological model was used to evaluate whether reduction scenarios meet such a water quality standard before assessing the management costs. The most cost-effective option to achieve the nutrient load reduction to the lake to meet this policy target was a combination of mitigation practices and land use change in the catchment. The current practice of alum dosing of two tributaries to the lake was instrumental in meeting water quality targets under current land use and resulting nutrient loads from the catchment. Best water quality outcomes were achieved by a conversion of intensive land use types to exotic or indigenous forest. This option also showed the best economic outcomes, when non-market values including ecosystem services values were considered. Results here show the importance of integrating ecological and economic assessments for best management outcomes. They also show the economic significance of preserving and restoring ecosystems.
	This thesis has revealed how environmental and social lag times can hinder the success of lake restoration actions, which at times can lead to irreversible degradation. It has shown the importance of making environmental decline visible in the public sphere, and the integration of science and policy to achieve effective management action. It has revealed how lake ecosystems are a major economic asset as well as being highly important for the provisioning of ecosystem services. The research has illustrated the economic potential of ecosystem services in the catchment. Response lags and ensuing degradation, as well as the economic importance of the lake ecosystem and its surrounding catchment mean that it is crucial to assess lake and land management in an integrated fashion. To restore the lake and maintain a resilient ecosystem, long term reduction of nutrient losses from intensive agriculture is an important component complementing in-lake restoration actions. This can be achieved through a combination of mitigation options reducing nutrient losses from intensive land use types, as well as land use change away from these types. This research analysed the management of both land and lake elements of a lake ecosystem. It has integrated analysis of ecological processes with an economic assessment of lake and catchment ecosystem services, and placed this within a policy and management context. The integration of lake and catchment, and ecology and economics in an applied context contributes to shifting research and management focus towards more integrated assessments, taking ecological, economic, social and cultural values into consideration.

text: Restoring freshwater quality: an integrated environmental, economic and ecosystem services assessment of reducing nutrient loads to Lake Rotorua The management of freshwater resources is a global concern as anthropogenic pressures on these resources have intensified. A decline in the quantity and quality of freshwater urgently requires concerted restoration actions to reverse the decline. Restoration of lakes is impacted by complex relationships of ecosystem responses to management actions, economic constraints, societal pressures and policy contexts. Research in this thesis was aimed at an integrated assessment covering these aspects to inform future lake restoration action. The overarching objective of this thesis is to evaluate ecological and economic aspects of lake restoration, assessing the economic importance of ecosystems through exploring the costs of restoring and managing them, and assessing the ecological effectiveness of restoration actions. A focus was the evaluation of ecosystem services provided by a lake and its catchment, and uses quantitative analysis to study lake management dynamics to analyse what impedes successful lake restoration.
	This research uses a case study of Lake Rotorua, central North Island, New Zealand. Like many lake ecosystems, this lake has been subject to pressures from human activity for decades, driving eutrophication and decline in ecosystem health. Land use has played a major role in nutrient enrichment of this lake. Restoration actions have been targeted at limiting nutrient loss from land, and reducing internal loading of the lake through engineering solutions. The aim of the research here was to analyse historical management responses and current management options alongside economic values of the lake and the catchment. The interdisciplinary assessment is aimed at connecting the lake to the catchment, as well as ecological to economic and policy assessments; such an integrated approach provides insight not only on the restoration of Lake Rotorua, but can also contribute to the management of lakes throughout New Zealand.
A main aim was to offer an integrated environmental, economic and policy assessment of the process of restoring water quality by reducing nutrient loads from the catchment alongside engineering options designed to reduce nutrients within the lake. The objectives for this thesis were to (1) explore a number of underlying drivers of lake management and the mechanisms for implementation of restoration initiatives, historically and in present times, (2) analyse ecosystem services and associated economic values of the lake ecosystem that are currently not valued by markets, and (3) evaluate cost-effectiveness of options to manage nutrient loads to the lake and internal loads through in-lake mitigation options, synthesising information on possible environmental outcomes and economic benefits for the lake and its catchment.
Several different methods were used to address these research objectives. To analyse the drivers of ecosystem degradation and resulting management initiatives, water quality data and research publications on Lake Rotorua were collected from 1922 to 2012. These data were categorised using the Drivers-Pressures-State-Impact-Response (DPSIR) model. Important management and environmental changes were used as independent variables in the year of their occurrence. Results of a Generalised Maximum Entropy (GME) regression, a specialised multinomial regression that is suitable for small datasets with a diverse range of variables (binary and continuous), showed that management was reactive, and policy responses (followed by regulatory interventions) often took effect only when ecosystem decline was already well advanced. There was also a disconnect between land use intensification and its role in driving water quality change, and long social lag times between the recognition of the environmental issue and a policy response delayed implementation of restoration actions.
To complement the historical study of lake restoration, the economic value of the lake and costs associated with degradation were evaluated to inform future management. Based on standard ecosystem services classification systems such as the Millennium Ecosystem Assessment in 2005, five different ecosystem services provided by the lake (habitat provision, food, nutrient processing, aesthetics, and recreation) were assessed. A range of direct and indirect valuation approaches, including existence value, hedonic pricing, and replacement cost, were used to assess the annual economic value of the lake ecosystem. A range of direct and indirect valuation concepts, including existence value, hedonic pricing and replacement cost, were used to assess the annual economic value of the lake ecosystem. A potential damage cost of the impacts of continued eutrophication was estimated as part of this economic assessment based on the current value of the lake and estimated reduction factors in ecosystem service provision and associated values.
To assess the effectiveness of options to reduce nutrient loads to the lake, a range of nutrient load scenarios was analysed for their effect on lake water quality using a hydrodynamic-ecological lake model (DYRESM-CAEDYM). Options needed to meet nutrient reductions as key component of a lake water quality target set by policy included mitigation on land, mitigation in the lake, and land use change. Different costs were attributed to each option, including lake and land mitigation costs. Values of different land use types and ecosystem services values of the catchment were included in the analysis. Costs and changes in values were determined for each scenario, to integrate an analysis of environmental effectiveness and costs of management options. Costs associated with these options were determined to illustrate the environmental effectiveness and potential costs of management options.
	Main findings of this thesis are that freshwater management is subject to response lags between the recognition of environmental decline and the restorative action undertaken to address this decline. These lags relate to the visibility of environmental problems in the public sphere, with action often only undertaken once effects such as lake weeds, low water clarity and possibly toxic algal blooms impact the public. Social lag times also exist as part of the general bureaucratic management process, and within scientific research to inform management. Lags mean that ecosystem degradation can be allowed to proceed until impacts, at times, become irreversible. This research found that a better integration of science and policy could inform management decision making by providing a holistic framework integrating ecological knowledge, pursuits of economic growth and societal constraints.
The ecosystem services value of Lake Rotorua based on the ecosystem services of food, habitat provision, nutrient processing, aesthetics and recreation was calculated to be $100-145 million per year. Ecosystem services provided by the catchment based on the current land use types were $176 million annually. A policy target for water quality was set for the lake. The ecological model was used to evaluate whether reduction scenarios meet such a water quality standard before assessing the management costs. The most cost-effective option to achieve the nutrient load reduction to the lake to meet this policy target was a combination of mitigation practices and land use change in the catchment. The current practice of alum dosing of two tributaries to the lake was instrumental in meeting water quality targets under current land use and resulting nutrient loads from the catchment. Best water quality outcomes were achieved by a conversion of intensive land use types to exotic or indigenous forest. This option also showed the best economic outcomes, when non-market values including ecosystem services values were considered. Results here show the importance of integrating ecological and economic assessments for best management outcomes. They also show the economic significance of preserving and restoring ecosystems.
	This thesis has revealed how environmental and social lag times can hinder the success of lake restoration actions, which at times can lead to irreversible degradation. It has shown the importance of making environmental decline visible in the public sphere, and the integration of science and policy to achieve effective management action. It has revealed how lake ecosystems are a major economic asset as well as being highly important for the provisioning of ecosystem services. The research has illustrated the economic potential of ecosystem services in the catchment. Response lags and ensuing degradation, as well as the economic importance of the lake ecosystem and its surrounding catchment mean that it is crucial to assess lake and land management in an integrated fashion. To restore the lake and maintain a resilient ecosystem, long term reduction of nutrient losses from intensive agriculture is an important component complementing in-lake restoration actions. This can be achieved through a combination of mitigation options reducing nutrient losses from intensive land use types, as well as land use change away from these types. This research analysed the management of both land and lake elements of a lake ecosystem. It has integrated analysis of ecological processes with an economic assessment of lake and catchment ecosystem services, and placed this within a policy and management context. The integration of lake and catchment, and ecology and economics in an applied context contributes to shifting research and management focus towards more integrated assessments, taking ecological, economic, social and cultural values into consideration.

year: 2017

title: Raising Māori Medium Students' Academic Oral Language Proficiency Through Self and Peer Assessment

authors: Shandley, Rosina Mary

subjects: Māori Medium Education

abstract: In 2012 there were 24,474 year 1 to 8 students being educated in the range of Māori medium bilingual and immersion programmes that exist throughout Aotearoa. This figure made up 25% of the total primary school population.

To ensure the survival of te reo Māori, and the cognitive advantages associated with bilingualism, Māori medium students need to reach a high level of proficiency in both the English and Māori languages over their time at school. They need to develop their language skills beyond basic conversational competency to academic language proficiency.

As well as academic success, Māori medium whānau expect their students to gain a level of competence in te reo Māori that enables them to actively engage in authentic Māori cultural contexts. This is crucial as the interruption to the intergenerational transfer of te reo Māori caused by colonisation means that today Māori medium graduates make up the main pool of speakers who can transmit our language into the future.

Substantial research has evidenced effective pedagogies for supporting students’ second language acquisition internationally. However, to date there have been no empirical studies to evidence effective second language pedagogies that can raise Māori medium students’ academic language in particular. This study aimed to bridge that gap by providing evidence of effective classroom practices that can raise Māori medium students’ academic language proficiency, with a particular focus on oral language competency.

This action research project aimed to raise a group of Māori medium students’ academic oral language proficiency through the practice of self and peer assessment. The participants were a group of eight year 5 and 6 students being educated in a level one Māori medium classroom in a mainstream school in Southland, New Zealand.

Over the 20 weeks of the study the students used a newly developed language matrix of writing outcomes to self and peer assess their learning in their literacy programme. The quantitative and qualitiative results of the study revealed that the confluence of self and peer assessment practices and the new language scaffolds raised the students’ academic oral and written language competency significantly beyond what was normally expected in a Māori medium programme in 20 weeks.

The study findings provide an option for those teachers wishing to develop their Māori medium students’ academic Māori language proficiency. The study also highlights the need for further research into Māori language acquisition pathways, to inform Māori medium oral language progressions and associated assessment development.

text: Raising Māori Medium Students' Academic Oral Language Proficiency Through Self and Peer Assessment In 2012 there were 24,474 year 1 to 8 students being educated in the range of Māori medium bilingual and immersion programmes that exist throughout Aotearoa. This figure made up 25% of the total primary school population.

To ensure the survival of te reo Māori, and the cognitive advantages associated with bilingualism, Māori medium students need to reach a high level of proficiency in both the English and Māori languages over their time at school. They need to develop their language skills beyond basic conversational competency to academic language proficiency.

As well as academic success, Māori medium whānau expect their students to gain a level of competence in te reo Māori that enables them to actively engage in authentic Māori cultural contexts. This is crucial as the interruption to the intergenerational transfer of te reo Māori caused by colonisation means that today Māori medium graduates make up the main pool of speakers who can transmit our language into the future.

Substantial research has evidenced effective pedagogies for supporting students’ second language acquisition internationally. However, to date there have been no empirical studies to evidence effective second language pedagogies that can raise Māori medium students’ academic language in particular. This study aimed to bridge that gap by providing evidence of effective classroom practices that can raise Māori medium students’ academic language proficiency, with a particular focus on oral language competency.

This action research project aimed to raise a group of Māori medium students’ academic oral language proficiency through the practice of self and peer assessment. The participants were a group of eight year 5 and 6 students being educated in a level one Māori medium classroom in a mainstream school in Southland, New Zealand.

Over the 20 weeks of the study the students used a newly developed language matrix of writing outcomes to self and peer assess their learning in their literacy programme. The quantitative and qualitiative results of the study revealed that the confluence of self and peer assessment practices and the new language scaffolds raised the students’ academic oral and written language competency significantly beyond what was normally expected in a Māori medium programme in 20 weeks.

The study findings provide an option for those teachers wishing to develop their Māori medium students’ academic Māori language proficiency. The study also highlights the need for further research into Māori language acquisition pathways, to inform Māori medium oral language progressions and associated assessment development.

year: 2013