bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bioprocessing of Marine Crustacean Shell Waste
Authors: Healy M. , Green A. , Healy A. 
Published: August 2003

AbstractThe anaerobic fermentation of waste prawn shell (Nephrops norvegicus) using lactic acid bacteria, in combination with especially selected proteolytic enzyme producing bacteria, has been established as an effective method for breaking down shell waste and isolating the valuable components contained within the shell structure. One of these components is the biopolymer chitin, which has numerous industrial applications and has traditionally been produced by a harsh chemical method which is extremely hazardous, energy consuming and ultimately damaging to the environment as it employs high concentrations of mineral acid and alkali. This qualitative study investigates the potential of prawn shell fermentation to provide a multi‐product process, thereby eliminating waste and generating revenue. Fermentations were carried out in a bench‐top, stirred tank bioreactor (5‐litres). Various components of the fermentation product were analysed. The chitinous residues were characterised by CHN and calcium analysis. The composition of the protein mixture in the fermentation liquor was assessed by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS‐PAGE). Two‐dimensional SDSPAGE followed by mass spectrometry allowed remaining proteins in the liquor to be identified. Carotenoid pigments in the liquor, potentially applicable in animal feed supplements, were investigated for their extractability in various solvents. A fine, white precipitate that is formed in the fermentation broth was also examined.Key results of the study showed that the unique microbial mixture used in the fermentation of prawn shell waste served to achieve the desired objectives i.e. (i) the production of a purified chitin with calcium removal as high as 93.8%; (ii) the production of a pigmented liquor containing peptides, amino acids only a few intact proteins. Sarcoplasmic calcium‐binding protein was consistently found as a surviving protein in the fermentation broth. This study demonstrates the use of a biotechnological process as an alternative to the traditional chemical approach used in the manufacture of chitin. Trials have begun to assess the nutritive value of the liquor in lobster farming while biotransformation studies on bioprocessed chitin are ongoing.
Aerobic and Anaerobic Reduction of Cr(VI) by Shewanella oneidensis Effects of Cationic Metals, Sorbing Agents and Mixed Microbial Cultures
Authors: Lowe K. L. , Straube W. , Little B. , Jones‐Meehan J. 
Published: August 2003

AbstractThe aim of the present study was to demonstrate the loss of Cr(VI) from aqueous solutions via microbial Cr(VI) reduction. Aerobic, anaerobic and microaerophilic cultures of Shewanella oneidensis were tested for Cr(VI) reduction under a variety of conditions (i.e., various Cr(VI) concentrations, carbon sources, pH, temperature, bacterial cell densities, presence of cationic metals, sea sand, illite clay, heterologous bacteria commonly found in soil and water or the soluble electron shuttle anthraquinone 2,6 disulphonate [AQDS]). Optimum reduction of 5 mg/l Cr(VI) was observed at: pH 7, at 25–30 °C and in lactate‐amended cultures. Anaerobic cells reduced Cr(VI) at an average rate of 28 ng Cr(VI)/min × mg protein versus 13 ng Cr(VI)/min × mg protein for aerobically grown cells. The presence of cationic metals [Co(II), Ni(II)] inhibited the reduction of 50 mg/l Cr(VI) by aerobic S. oneidensis cultures but not anaerobic or microaerophilic cultures. In aerobic cultures, toxic effects due to high levels (50 mg/l) of Cr(VI) and cationic metals were alleviated by the presence of sand and illite clay particles, which sorbed Cr(VI). When 50 mg/l Ni(II) was present, more Cr(VI) was reduced by aerobic S. oneidensis cultures containing either sand or illite clay versus cultures lacking these amendments. Addition of an electron shuttle (AQDS) to the medium also enhanced 50 mg/l Cr(VI) reduction in the presence of 50 mg/l Ni(II). Cr(VI) reduction rates were similar with and without AQDS when 50 mg/l Co(II) was present. Reduction of 50 mg/l Cr(VI) was facilitated by the addition of other bacteria (Acinetobacter calcoaceticus, Pseudomonas putida and Bacillus circulans) in mixed cultures with S. oneidensis.This study demonstrates that aerobic, anaerobic and microaerophilic cultures of S. oneidensis reduce Cr(VI). Bacterial mixtures, addition of AQDS and presence of sand or illite clay may enhance Cr(VI) reduction by this bacterium in the presence of inhibitory agents.
Bioremediation of Concrete Contaminated with n‐Hexadecane and Naphthalene
Authors: Beklemishev M. K. , Kozliak E. I. 
Published: August 2003

AbstractRetention/leaching and bioremediation of n‐hexadecane and naphthalene absorbed in building grade concrete were investigated. Retention studies showed that up to 20 mg of n‐hexadecane were irreversibly absorbed per 1 g of concrete (not leached out by either water or aqueous solutions of surfactants). Bioremediation studies were conducted using three naturally occurring bacterial strains including Pseudomonas aeruginosa PG201 and soil microorganisms. Incubation of contaminated concrete pieces with bacterial suspension in shaking flasks resulted in the biodegradation/biotransformation of 8–19% of n‐hexadecane or 28–35% of naphthalene, whereas neat hydrocarbons were completely degraded. Naphthalene removal was similar with and without bacteria, and only the destination of the labelled carbon was different. Direct application of biomass on contaminated concrete (“overlay procedure”) proved to be more efficient. Up to 70–80% of n‐hexadecane and 20–55% of naphthalene (up to 80% combined with evaporation) were removed when using agar plates or filter paper with biomass. Overlay protocols using large amounts of water proved to be more efficient for the biological removal of naphthalene but detrimental for the removal of n‐hexadecane. The latter was greater with low amounts of water. Evidence obtained shows that the hydrocarbon diffusion within the pores of concrete is the rate‐limiting step for bioremediation.
Biofiltration for the Treatment of Complex Mixtures of VOC – Influence of the Packing Material
Authors: Aizpuru A. , Khammar N. , Malhautier L. , Fanlo J. L. 
Published: August 2003

AbstractCurrently air biofiltration is largely considered for the removal of Volatile Organic Compounds (VOC) from polluted airstreams. In order to select a suitable packing material for the treatment of VOC polluted air and better understand the influence of the packing material properties upon the removal efficiency, a mixture of eleven VOC was treated in two down‐flow biofilter units packed with either peat or Granular Activated Carbon (GAC) and functioned under similar operating conditions for 92 days. Using the peat biofilter under steady‐state conditions achieved a removal efficiency of 90% greater than the 80% achieved using the GAC filter. Moreover, in both cases, a stratification of the abatement along the column was observed but it differed according to the type of the packing material used. For the peat biofilter, elimination of oxygenated compounds occurred in the first 50 cm of the column, whereas aromatic and halogenated compounds were treated in the segments closer to the outlet. In contrast, with GAC, the removal of oxygenated and aromatic compounds took place along the height of the column. For the removal of microorganisms fixed on peat and activated carbon particles, the crushing with an ultra‐turrax was the most efficient dispersing method, compared to agitation with a vortex and ultrasound. The counting of microorganisms using three culture media [Luria Bertoni (LB); Plate Count Agar (PCA); Tryptic Soy Agar, tenfold diluted (TSA 1/10)] demonstrated that the TSA 1/10 was likely most suitable for the recovery of the peat biofilter microflora (TSA 1/10: 5.6 × 109 CFU/g of dry peat, PCA: 1.5 × 109 CFU/g of dry peat, LB: 0.3 × 109 CFU/g of dry peat) probably due to the dominance of oligotrophic bacteria, whereas for the activated carbon biofilter there was no significant difference (PCA: 4.4 × 109; LB: 4.2 × 109; TSA 1/10: 4.5 × 109 CFU/g of dry activated carbon) between these media suggesting that oligotrophic and zymogeneous bacteria are likely in the same proportion.The results illustrated that even the removal efficiency is associated with the pollutant properties; it was assumed that the sorptive properties of GAC could modify the VOC degradation mechanisms and then entail a real reduction of the removal efficiency.
A Soluble Flavoprotein Contributes to Chromate Reduction and Tolerance by Pseudomonas putida
Authors: Gonzalez C. F. , Ackerley D. F. , Park C. H. , Matin A. 
Published: August 2003

AbstractAs a consequence of its toxicity, the accumulation of chromate [Cr(VI)] in drinking water poses a serious risk to human health. Conventional approaches to groundwater remediation and the regeneration of potable water supplies are expensive and have, to date, been limited in their effect. From a biological perspective, chromium(III) compounds, the end products of bacterial chromate reduction, are less dangerous; not only are they less toxic than chromate, they also have very low solubility, restricting their spread and their biological availability. Thus, reduction of chromate by bacteria is an attractive strategy for its remediation. Through biomolecular engineering, it should be possible to improve the chromate‐reducing activities of wild type bacterial enzymes, and to produce bacteria capable of expressing such activities at a high level under nutrient‐poor and stressful field conditions. With this goal in mind, we have identified, purified and characterised a chromate‐reducing flavoenzyme from Pseudomonas putida. The results presented here indicate that this enzyme is an efficient reducer of Cr(VI) in vitro, and also plays an important role in chromate detoxification in vivo. Our ongoing studies have also identified areas where improvement in these enzymes would enhance chromate bioremediation.
Assimilation of Nitrogen Dioxide in Selected Plant Taxa
Authors: Takahashi M. , Kondo K. , Morikawa H. 
Published: August 2003

AbstractThe production of a novel “nitrogen‐dioxide‐philic plant” that can grow with NO2 as the sole nitrogen source was investigated as a possible solution to pollution. 217 plant taxa were screened for the assimilation of NO2, among them 50 wild herbaceous plants collected from roadsides, 60 cultivated herbaceous plants and 107 cultivated woody plants. It was discovered that the NO2‐derived reduced nitrogen [μg N/mg dry weight] differed by a factor of 657 between the highest (Eucalyptus viminalis, 6.57) and lowest (Tillandsia ionantha and T. caputmedusae, 0.01) level in the 217 taxa. The capability of plants to assimilate NO2 was also found to change in a family‐dependent manner. Compositae, Myrtaceae, Salicaceae and Solanaceae had taxa with high NO2 assimilation capability, while none of the Gramineae, Theaceae and Rosaceae plants examined showed high NO2 assimilation capability. The 217 taxa included two species of the Solanaceae family (tobacco and petunia), both of which showed a high NO2 assimilation and their reduced nitrogen derived from NO2 was the third and twenty‐sixth highest. This suggested that the Solanaceae family includes plants of high NO2 assimilation.Therefore, in this study eight taxa of the Solanaceae family and four taxa of other families were investigated for NO2 assimilation in the same manner as reported previously by the fumigation of plants with 15N‐labelled NO2 followed by the mass spectroscopic analysis based upon the reduced nitrogen derived from NO2. The eight taxa Solanaceae included tobacco (Nicotiana tabacum) and petunia (Petunia X hybrida), ground cherry (Physalis alkekengi var. franchetii), tomato (Lycopersicon esculentum), datura (Datura innoxia), potato vine (Solanum jasminoides), red pepper (Capsicum annuum) and green pepper (Capsicum annuum var. grossum SENDTN.). The four taxa included two ivy cultivars (Hedera helix “Pittsburgh” and Hedera helix “Wonder”), an evergreen creeper (Ficus thunbergii) and kenaf (Hibiscus cannabinus).Among the twelve taxa, kenaf, tobacco and ground cherry showed the highest, second and third highest values, respectively, of reduced nitrogen derived from NO2 in plants, which reflects the capability to assimilate NO2‐nitrogen. The quantitative significance of these findings is discussed in relation to the reduction of nitrogenous pollution by the atmospheric NO2 pollution.
Conversion of the Nitrate Nitrogen and Nitrogen Dioxide to Nitrous Oxides in Plants
Authors: Hakata M. , Takahashi M. , Zumft W. , Sakamoto A. , Morikawa H. 
Published: August 2003

AbstractTobacco and wheat are known to emit nitrous oxide (N2O). Provided that N2O is a greenhouse gas about 300 times worse than carbon dioxide in its potential for global warming, it is an intriguing and important subject, whether this activity is commonly present in other plants. In this study, 17 plant taxa that had been cultured aseptically were fed with15N‐labelled nitrate for one week (feeding period). The plant taxa were then transferred to a medium with non‐labelled nitrate in gas‐sealed pots and cultured for another week (emission period). The amount of labelled N2O emitted from the plants during the emission period was determined. This value reflects only a part of the capability of plants to convert nitrate to N2O, because the amount of N2O determined here does not correspond to the total N2O emission from plants, but to only an15N‐labelled N2O fraction emitted during the emission period from nitrate taken up into the plants during the feeding period. It was discovered that all of the 17 plant taxa analysed, except forEucalyptus viminalis,showed emission of15N2O. The emission ranged from 0.45 ± 0.20 ng N2O/g fresh weight (kenaf) to − 0.012 ± 0.12 ng N2O/g fresh weight (Eucalyptus viminalis). This activity of converting nitrate to N2O is obviously common in plants with some exceptions. There was more than a 58‐fold variation between the highest (Hibiscus cannabinus) and the second lowest (Nicotiana tabacum) capability to convert nitrate to N2O among the 17 plant taxa. The present result indicates that the potential of plants to convert nitrate to N2O highly varies among the plant species as in the case of the assimilation of nitrogen dioxide (N2O) where more than a 600‐fold variation was observed among 217 plant taxa. A negative correlation was obtained for N2O emission and NO2assimilation (r= 0.72).This is the first report where there was a competitive interaction between the assimilation and dissimilation activities in plants. It was also found that wild type and transgenic tobacco are able to convert NO2to N2O when they were fumigated with15N‐labelled NO2. However since the N2O emission values observed in this study were approximately three orders of magnitude smaller than those observed with wheat leaves, the evaluation of the environmental significance of the N2O emission by plants must await quantitative analysis using the present system to figure out the full N2O emission capability of plants.
Productivity, Protein Content and Nutrient Removal from Anaerobic Effluents of Coffee Wastewater in Salvinia minima Ponds, under Subtropical Conditions
Authors: Olguín E. J. , Rodríguez D. , Sánchez G. , Hernández E. , Ramírez M. E. 
Published: August 2003

AbstractSalvinia minima is an aquatic fern which presents several advantages for the phytoremediation of wastewater. However, there is no information available for the operation of Salvinia‐based systems (SBS) for nutrient removal from organic matter enriched wastewater. The objective of this work was to establish the optimum range of some key parameters for the operation of Salvinia minima ponds treating anaerobic effluents of coffee wastewater (AECWW). Batch cultures were performed outdoors, under subtropical conditions (Xalapa, Veracruz, Mexico). At the first stage, various pH levels were tested. After choosing the optimum pH, two pond depths were evaluated (0.10 m and 0.27 m). It was found that the productivity in AECWW was strongly affected by the pH, as it decreased with the increase in the pH. In fact, growth was completely inhibited at pH 8.0. In contrast, productivity at a pH of 6.0 and a pond depth of 0.27 m during the summer was equivalent to 27.92 ton/ha × year. The percentage of TKN removal increased with the pH value: 51 ± 2.28% at pH 5.0; 78 ± 1.47% at pH 6.0 and. 97 ± 0.80% at pH 8.0. A similar situation was found for the case of NH4‐N removal: (55 ± 0.44%, 80 ± 1.1%, 99 ± 0.02%). The depth of the culture had influence on the productivity, protein content and nutrient removal. It was concluded that Salvinia minima is an adequate choice for the treatment and recovery of nutrients from AECWW. The pH for optimal operation of this type of pond was 6.0. The depth of the water column should be adjusted to 0.10 m for attaining a maximum relative removal efficiency (in terms of g NH4‐nitrogen/l × d), although the productivity would not be at its maximum under these conditions. On the contrary, depth should be adjusted to 0.27 m for reaching the maximum absolute removal efficiency (considering the total volume of the reactor) and the maximum productivity. During the late autumn and winter period, the AECWW should be diluted 1:2 in order to enhance ammonia nitrogen removal.
A Differential Availability Enhancement Factor for the Evaluation of Pollutant Availability in Soil Treatments
Authors: Poggi‐Varaldo H.M. , Rinderknecht‐Seijas N. 
Published: August 2003

AbstractAn availability enhancement factor (AEF) is proposed and its usefulness for determining the effectiveness of desorption treatments of pollutants from soils is discussed. In addition, its relationship to a new Coefficient of Hysteresis (CH) is derived. The AEF was defined as the ratio of the slope of the desorption curve of a given pollutant with a surfactant or solvent treatment to the slope of the corresponding desorption curve of a reference treatment. This factor is shown to be useful for the quantification of the effect of a given soil treatment (with surfactants, biosurfactants, solvents) on the eventual improvement of the pollutant desorption and availability for biodegradation or further physicochemical removal. Several easy algebraic equations are developed for finding the values of the AEF in the most common desorption cases (linear, Freundlich, and Langmuir isotherms). Data from the refereed literature were used to show how the AEF concept works when a biosurfactant is applied to increase the desorption of polynuclear aromatic hydrocarbons from soils. The AEF concept allows for more objective decisions regarding the selection of desorption treatments of pollutants from soils and sediments to be made.
Biotechnological Approaches for Enhancing Phytoremediation of Heavy Metals and Metalloids
Authors: Terry N. , Sambukumar S. V. , LeDuc D. L. 
Published: August 2003

AbstractPhytoremediation, the use of plants and their associated microbes to accumulate, detoxify and/or stabilise contaminants, is an environment‐friendly and sustainable means of remediating contaminated soil and water. Phytoremediation has been an important aspect of constructed wetlands, which have been used successfully to detoxify large volumes of wastewater with dilute concentrations of contaminants. The usefulness of phytoremediation appears to extend to a wide variety of contaminants, and a recent study demonstrated its possible application for selenocyanate. Genetic engineering approaches are currently being used to optimise the metabolic and physiological processes that enable plants to phytoremediate sites contaminated with heavy metals and metalloids. Over‐expressing enzymes catalysing rate‐limiting steps in the sulphate assimilation and phytochelatin synthesis pathways has been shown to confer increased tolerance to and the ability to accumulate higher concentrations of selenium and cadmium, respectively. Recent research in our laboratory is aimed at determining the regulatory genes involved in heavy metal accumulation and detoxification in hyperaccumulating plants that could then be transferred to fast‐growing, high biomass plant species for phytoremediation. Microbes isolated from highly contaminated environments represent another potentially huge reservoir of new genes and unique metabolic capabilities that could be transferred to plants to enhance their phytoremediation potential.
Phytoremediation of Solid Oil Shale Waste from the Chemical Industry
Authors: Truu J. , Kärme L. , Talpsep E. , Heinaru E. , Vedler E. , Heinaru A. 
Published: August 2003

AbstractThe processed oil shale (semi‐coke) contains several organic and inorganic compounds (oil fractions, sulphides, phenolic compounds, polycyclic aromatic hydrocarbons) and is highly toxic. The solid waste deposit is a source of toxic phenolic leachate, which is discharged into nearby bodies of water without any treatment. Field experiments were carried out in order to test the effect of phytoremediation to enhance in‐situ microbial biodegradation of pollutants in semi‐coke. Four pilot test plots (50 m2) were established at a semi‐coke deposit in July 2001. The growth rate of plants was approximately twice higher in the case of soil amendment. The phytoremediation increased the number of biodegradative bacteria and diversity of microbial community in semi‐coke. The presence and diversity of multi‐component phenol hydroxylase (mPH) genes in the environment were assessed using the microbial DNA directly extracted from semi‐coke. The changes in the genotypes of mPHs indicated shifts in the microbial community structure towards the more efficient degradation of pollutants due to plant treatment. Within a four‐month period starting from the establishment of test plots in July, the concentration of phenolic compounds decreased three times in average and the concentration of oil products up to ten times, compared to the control plot.
Tailored Synthesis of Poly([R]‐3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHB/HV) inRalstonia eutrophaDSM 428
Authors: Zinn M. , Weilenmann H.‐U. , Hany R. , Schmid M. , Egli Th. 
Published: August 2003

AbstractRalstonia eutrophawas grown in a chemostat at a dilution rate ofD= 0.1 ± 0.01 h−1under the conditions of simultaneous limitation by carbon (butyric and/or valeric acid) and nitrogen (ammonium). In order to achieve a physiological state with a high cellular polyhydroxyalkanoate (PHA) content, the ratio of total carbon to nitrogen of the feed medium was kept constant at 17 mol C/molN and only the ratio of butyric to valeric acid was varied in the carbon feed. When only butyric acid was fed, poly([R]‐3‐hydroxybutyrate) (PHB) was isolated. For substrate mixtures consisting of butyric and valeric acid, and valeric acid alone, theco‐polymer poly([R]‐3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHB/HV) was incorporated with a maximum content of (R)‐3‐hydroxyvalerate of 62 mol%. The melting temperature of PHA decreased from 178 °C for PHB to about 80 °C for PHA with the highest HV content. The molecular weight (Mw) of the polymer was between 0.9 and 1.2 × 106with a polydispersity of 3 ± 0.3. The polymer composition in the cells was a non‐linear function of the substrate mixture. It was concluded that dual (C, N) limited growth conditions in chemostat cultures could be used to tailor the composition of PHB/HV in an accurate way, which is not possible when using N limited batch cultures.