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பயோபிராசசிங் & பயோடெக்னிக்ஸ் ஜர்னல்

ஐ.எஸ்.எஸ்.என்: 2155-9821

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தொகுதி 1, பிரச்சினை 4 (2011)

ஆய்வுக் கட்டுரை

Insilico Screening and Comparative Study on the Effectiveness of Textile Dye Decolourization by Crude Laccase Immobilised Alginate Encapsulated Beads from Pleurotus Ostreatus

Chinnathambi Velu, Ezhilarasan Veeramani, Sridhar Suntharam, Kasinathan Kalimuthu

The necessity to safeguard the environment has increased the potential of enzyme usage in textile processing to ensure eco-friendly production. Laccase enzyme formulation has been used in textile processing such as biobleaching, dyeing, rove scouring, finishing, neps removal, printing, wash-off treatment, dye synthesis and effluent treatment. However, a high cost associated with biocatalyst production is still a hindrance to their use. Pleurotus ostreatus is a white-rot fungus that produces a ligninolytic enzyme complex rich in several laccase iso-enzymes. The main objective of this study is optimize influence of pH and stability of divalent metal ion- immobilzed crude laccase enzyme towards decolourization of prototype textile dyes such as Reactive red 80 (Red F3B) and Reactive blue 21(T Blue G). Wheat bran is used as a lead candidature for production of lignolytic enzyme using Pleurotus osteratus by solid state fermentation. Two divalent metal ions such as Zn2+ and Ca2+ were selected to study the influence of metal ions towards the dye decolourization. Results revealed that Ca2+ ion was better compared to Zn2+ ion towards enzyme immobilization and its influence on dye decolourization in the optimal pH 5.5. Finally, interactions between laccase and dyes were studied exclusively using Insilco structure based molecular docking methods. 
ஆய்வுக் கட்டுரை

Effect of Inducers and Physical Parameters on the Production Of L-Asparaginase Using Aspergillus Terreus

Moses Jeyakumar Rajesh, Leelavathy Rajesh, V.Satya veni, G.Thirumurugan, O.S.Sethuraman, Rajaram Sivasubramanian

An effort has been made to find the best medium and operating conditions for the production of extracellular L-asparaginase by Aspergillus terreus in shake culture fermentation through stepwise optimization strategies like studies on the effect of pH and temperature on L-asparaginase, studies on the enzyme activity in various concentration of L-glutamine and study the growth kinetics for L-glutamine medium. Our study shows that L- glutamine combined with L-asparagine influence the asparaginase production level and physical parameter such as pH and temperature has more contribution in enzyme production. The pH 8 and temperature 35°C found to be good environmental condition the production of extracellular L-asparaginase by Aspergillus terreus.

ஆய்வுக் கட்டுரை

Characterization of a High Activity (S)-Aminotransferase for Substituted (S)-Aminotetralin Production: Properties and Kinetics

Abraham R. Martin, David Shonnard, Sachin Pannuri and Sanjay Kamat

The production of substituted (S)-Aminotetralins requires biocatalyst that have high activities at high temperatures and considerable tolerance to amine donors to shift the reaction towards products. The biocatalyst used in this process are (S)-Aminotransferases. An (S)-aminotransferase of a high activity derived from Athrobacter citreous by directed evolution for the production of substituted (S)-aminotetralin was characterized in the form of whole cells. Its optimum conditions were pH 7 and 55 °C. Maximum activity was 0.21 mM/min per gram of whole cells. Substrate affinities were 750 mM for isopropylamine and 10.4 mM for substituted tetralone. A kinetic study to describe the production of substituted (S)-aminotetralin showed that two major reactions were involved: one enzyme catalyzed –by (S)-aminotransferase- that is the production of substituted (S)-aminotetralin from isopropylamine and substituted tetralone; the other a non-enzyme catalyzed reaction that forms a byproduct consisting in the imine formed by substituted tetralone and substituted (S)-aminotetralin. 
ஆய்வுக் கட்டுரை

A Solid and Robust Model for Xylitol Enzymatic Production Optimization

Branco R. F, Santos J. C and Silva S.S

Xylitol production by fermentation process is widely studied. However, few works describes the enzymatic production of this polyalcohol. This works aims to determine a model that could explain the xylitol enzymatic production as a function of major variables in this process. For this purpose we applied an adequate statistical analysis and response surface methodology (RSM). Initially, variables were selected using a 25-1 fractioned factorial design. Xylose and NADPH concentrations were chosen for the optimization experiments. In order to use the RSM, experiments according to a 22 factorial design with star points and triplicate in the center were carried out. The statistical analysis resulted in a quadratic model which could explain 98.6 % of the volumetric productivity in xylitol in function of xylose and NADPH concentrations. Using predicted experimental conditions of 7.0, 25ºC, 1.2 mM NADPH, 0.34 M xylose, glucose 0.2 U mg-1 xylose reductase and 0.2 U mg-1 glucose dehydrogenase, this solid model was possible to achieve in batch reaction a xylitol volumetric productivity of 1.58 ± 0.05 g L-1 h-1 with stoichiometric xylose/xylitol conversion efficiency. These values are considered higher and significant in comparing with the traditional fermentation processes. Our results contribute for development of a novel and promising alternative process for xylitol production. 
தலையங்கம்

Smoking Related Changes in Neurotransmitters in African Americans

Sudhish Mishra, Anita Mandal and Prabir K. Mandal

 Smoking is a most common way of tobacco consumption that provides a pleasurable effect by modulating neurotransmitters in the brain. African Americans (AA) have shown higher susceptibility to nicotine consumption and highest rate of mortality due to cancer. In this study we have examined the levels of 6 neurotransmitters in AA smokers and compared them with nonsmokers of same population. We observed decrease in plasma levels of glutamate and increase in serotonin, epinephrine and dopamine. The level of gamma amino butyric acid (GABA) and norepinephrine was not changed significantly. The results, in part, explain the basis of higher nicotine susceptibility in AAs and will be helpful to develop population specific strategies for smoking cessation.

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