Monday, November 20, 2017
Industrial Enzymes & Biofuels

Group Leader

 

 

Team members:

 

This group is involved in the isolation and purification of local thermophilic fungi for biotechnological purposes. These fungi have been extensively studied for cellulolytic and xylanolytic ability to utilize the lignocellulosic biomass raised on local soils along with saline effected soils. Mass balance studies of various lignocellulosic substrate has been carried out. Moreover, pretreatment of these substrate using chemicals and steam explosion was carried out in order to make them amenable to enzymatic hydrolysis and for bioconversion to ethanol using yeast. Simultaneous saccharification and fermentation to ethanol resulted in ~ 3% w/v ethanol yield. However, further scale up was cost intensive and needed either over-expressed enzymes by using genetic engineering or mutagenesis in order to obtain theoretical yields.

xylanase gene of Chaetomium thermophile were successfully cloned, sequenced and expressed in model yeast Pichia pastoris (Invitrogen, USA).  Similarly, Indigenous Humicola insolens avicelase and endoglucanase EG 2 and EG 5 genes were cloned and expressed in Trichoderma reesei (TUV, Austria) and P. pastoris. The expression of these genes showed better kinetic properties and induction of enzymes using methanol.

Thermotoga maritima (ATCC, USA), exoglucanase (avicelase), endoglucanase (Cel AB) and β-glucosidase genes were cloned and expressed in hosts Escherichia coli. The cellulases were produced up to shake flask and 10 L fermentor level. Thermostability of the cellulases was found to be effective over 100 °C, which can be of industrial importance.  

The thermophilic fungi have been used for strain improvement by mutagenesis (gamma, UV radiation and MNNG). Wild and mutant cultures have been developed using lignocellulosic substrates and nitrogen sources for optimal and economic production of enzymes in submerged and solid state fermentation in shake flask and 20-140 L bioreactor. Some of these cultures will now be used for scale up to 1000 L fermeters for some of the processes developed for industry viz-a viz; i) Thermostable xylanase for bleach-boosting of pulp for pulp and paper industry, ii) Fiber degrading enzymes for the poultry and ruminant feed, iii) Thermostable and neutral pH, cellulase for bio-stone washing and bio-finishing of garments.

The work on enzymes (glucoamylase, glucose isomerase, cellulase, protease and lipase) engineering has successfully enabled to increase in catalytic efficiency, change in pH and temp optimum involved, thermostability, shelf/half life, stability in organic solvents. Various techniques used involved vis-à-vis  i) Carboxyl and amino group modification of enzymes, ii) Enzyme modification through metals, iii) Enzyme immobilization on nano-particles and nano-porous materials, iv) Random mutagenesis for microbial strain development, v) Gene cloning and expression.

 

 

                                                     

 

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Facilities:

  • Bioreactors
  • HPLC
  • FPLC
   
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