title: Bacterial cellulose synthesis by gluconacetobacter xylinus: Enhancement via fed-batch fermentation strategies in Glycerol media

authors: Adnan, Azila Binti

abstract: Bacterial cellulose (BC) is an abundant polysaccharide, which is secreted by several genera of bacteria. It has remarkable characteristics, which include high purity, high tensile strength, high biocompatibility and non-toxic. The main feature that differentiates BC and plant cellulose (PC) is the absence of contaminants such as lignin, hemicellulose and pectin. However, the main drawbacks in producing BC are low yield and expensive carbon source. Due to that, this study was carried out to enhance BC volumetric productivity in fed-batch operation mode using glycerol as a carbon source. BC was produced in fill-and-draw and pulse-feed fed-batch cultures of Gluconacetobacter xylinus DSM 46604 in a 3-L bench-top bioreactor. The fed-batch fermentation trials were conducted in agitated and aerobic conditions at 30 ºC. For fill-and-draw fed-batch culture, a total of 24.2 g/L of BC accumulated in the bioreactor after 9 days, which corresponded to a yield and productivity of 0.2 g/g and 2.69 g/L/day, respectively. Pulse-feed fed-batch fermentation resulted in a yield and volumetric productivity of 0.38 g/g and 2.71 g/L/day, respectively. The pulse-feed fed-batch culture proved to be a better fermentation system for utilizing glycerol, which is a low-cost and abundant carbon source.

text: Bacterial cellulose synthesis by gluconacetobacter xylinus: Enhancement via fed-batch fermentation strategies in Glycerol media Bacterial cellulose (BC) is an abundant polysaccharide, which is secreted by several genera of bacteria. It has remarkable characteristics, which include high purity, high tensile strength, high biocompatibility and non-toxic. The main feature that differentiates BC and plant cellulose (PC) is the absence of contaminants such as lignin, hemicellulose and pectin. However, the main drawbacks in producing BC are low yield and expensive carbon source. Due to that, this study was carried out to enhance BC volumetric productivity in fed-batch operation mode using glycerol as a carbon source. BC was produced in fill-and-draw and pulse-feed fed-batch cultures of Gluconacetobacter xylinus DSM 46604 in a 3-L bench-top bioreactor. The fed-batch fermentation trials were conducted in agitated and aerobic conditions at 30 ºC. For fill-and-draw fed-batch culture, a total of 24.2 g/L of BC accumulated in the bioreactor after 9 days, which corresponded to a yield and productivity of 0.2 g/g and 2.69 g/L/day, respectively. Pulse-feed fed-batch fermentation resulted in a yield and volumetric productivity of 0.38 g/g and 2.71 g/L/day, respectively. The pulse-feed fed-batch culture proved to be a better fermentation system for utilizing glycerol, which is a low-cost and abundant carbon source.

year: 2021

title: Preparing pupils for peer or group response

authors: Foster, Rebecca

subjects: peer response

abstract: Teaching writing is a complex skill, and one that needs attention if student writing scores across New Zealand are to improve. The teaching of writing has changed over the years from a traditional product approach, where students wrote for the teacher, to a more collaborative approach where students work together as part of a writing community.
Peer or group response is one approach that teachers can use when building a writing community as part of their writing programme. This typically involves groups of students sharing and responding to writing, usually during the revision stage of the writing process. Students use the responses they receive from peers to revise their message, which in turn impacts on the quality of writing produced.
Preparing students for effective peer or group response is a sophisticated process that requires careful planning and preparation. This research used qualitative observations and interviews to investigate some of the ways that four teachers prepared their students for peer or group response in writing. The results of this study suggest that there are a number of ways to prepare students for response in writing and that teachers will coach students how to respond to their own and others’ writing differently, depending on the discourse/s of writing and teaching writing that they consciously or unconsciously subscribe to. This research also shows that response activities motivate students, and suggests the benefits of adopting a school-wide approach and involving teachers in professional development to help develop their identity as a writer.

text: Preparing pupils for peer or group response Teaching writing is a complex skill, and one that needs attention if student writing scores across New Zealand are to improve. The teaching of writing has changed over the years from a traditional product approach, where students wrote for the teacher, to a more collaborative approach where students work together as part of a writing community.
Peer or group response is one approach that teachers can use when building a writing community as part of their writing programme. This typically involves groups of students sharing and responding to writing, usually during the revision stage of the writing process. Students use the responses they receive from peers to revise their message, which in turn impacts on the quality of writing produced.
Preparing students for effective peer or group response is a sophisticated process that requires careful planning and preparation. This research used qualitative observations and interviews to investigate some of the ways that four teachers prepared their students for peer or group response in writing. The results of this study suggest that there are a number of ways to prepare students for response in writing and that teachers will coach students how to respond to their own and others’ writing differently, depending on the discourse/s of writing and teaching writing that they consciously or unconsciously subscribe to. This research also shows that response activities motivate students, and suggests the benefits of adopting a school-wide approach and involving teachers in professional development to help develop their identity as a writer.

year: 2014

title: Effects of industry on Maori cultural values: The case of the Tarawera River

authors: Dodd, Materoa

subjects: New Zealand

abstract: The research is a case study of the relationship between three tribes; Te Arawa, Tuwharetoa ki Kawerau and Ngāti Awa and the Tarawera River during the second half of the 20th century when the river was polluted with effluent from pulp and paper mills. It involves the cultural story of the Tarawera River as told by the iwi (tribes) of the river informed by Maori epistemologies and what has come to be known as a ‗kaupapa Maori research' approach. Reference is made to the history, legends, customs and lifestyle that have arisen from the relationship between iwi and the river. It includes comments on the pollution of the river from members of each iwi. The world views, experiences, and perceptions reported on here have forced a fundamental change on the iwi, a change that has affected their cultural and social relationship to the river. The price of economic development on the river has been cultural and ecological genocide. 
The cultural voice echoes a familiar story in indigenous communities. In the Maori context the research provides opportunities for further inquiry into determining the socio-cultural, economic and political future of the iwi of the river.

text: Effects of industry on Maori cultural values: The case of the Tarawera River The research is a case study of the relationship between three tribes; Te Arawa, Tuwharetoa ki Kawerau and Ngāti Awa and the Tarawera River during the second half of the 20th century when the river was polluted with effluent from pulp and paper mills. It involves the cultural story of the Tarawera River as told by the iwi (tribes) of the river informed by Maori epistemologies and what has come to be known as a ‗kaupapa Maori research' approach. Reference is made to the history, legends, customs and lifestyle that have arisen from the relationship between iwi and the river. It includes comments on the pollution of the river from members of each iwi. The world views, experiences, and perceptions reported on here have forced a fundamental change on the iwi, a change that has affected their cultural and social relationship to the river. The price of economic development on the river has been cultural and ecological genocide. 
The cultural voice echoes a familiar story in indigenous communities. In the Maori context the research provides opportunities for further inquiry into determining the socio-cultural, economic and political future of the iwi of the river.

year: 2010