Microbial Engineering

INDUSTRIAL BIOTECHNOLOGY  / Biofuels and Industrial Biotechnology

Research Interests

Second-generation biofuels, fungal and bacterial genome engineering, engineered cellulases, n- and iso-butanol production, 1,4-butanediol, alkane and cetearyl alcohol production.

Description of Research

Discovery and design of novel enzymes and enzyme systems for biofuels

Recent interest has shifted to non-food-based feedstock for biofuel production, in addition to issues of biomass burning, which has resulted in the exploitation of agricultural residues as feedstock. However, the recalcitrant nature of this biomass makes it extremely difficult to hydrolyze into fermentable sugar.

Filamentous fungi are found to be efficient in carbon cycling in nature and, therefore, are treated as potential sources of enzymes for converting recalcitrant lignocellulosic biomass into precursors for industrial purposes. We use an intense mathematical model-based screen to identify fungal isolates whose secretome can degrade biomass more efficiently than commercial cellulase formulations. Several enzymes have been characterised and engineered to increase efficiency. Prominent among these are cellobiohydrolase 1 (CBH1), Lytic Polysaccharide Monooxygenase (LPMO), and beta-glucosidase.  We have performed genome engineering of the new fungal isolate to disrupt its catabolite repressor and overexpress the cellulase gene activator to enhance enzyme production several-fold. Many leads have been obtained to understand the role of several unannotated transcription factors involved in cellulase production via transcriptomic and proteomic studies, which are being valorized to construct superior biocatalysts. The Group has identified a drug efflux mechanism of the hypercellulolytic fungus Penicillium funiculosum and developed strategies to block these efflux pumps to develop effective transformation tools for genome engineering. The highest enzyme titer-producing engineered fungal strain has been the scale-up to a pre-commercial 15,000 litre scale for use in lignocellulosic biomass hydrolysis. Efforts are being made with the help of funding from the Department of Biotechnology, Government of India, to produce recombinant fungal cellulase enzymes at a commercial scale and make them available for use at the 2G ethanol commercial plants.

Engineering microbes to produce biofuels and biochemicals

The Group works on metabolic engineering of bacteria to produce various fuels and chemicals. Butanol was made in E. coli by integrating the Clostridial pathway in its genome via the CRISPR/Cas9 technique, while isobutanol was made in Paenibacillus polymyxa by replacing its native 2,3-butandiol pathway. On the other hand, long-chain alkanes and alcohol are being made via metabolic model-assisted engineering of E. coli, with the highest titers reported so far. Efforts are also ongoing to produce 1,4-butanediol via novel pathway engineering with industry support.

Recent Publications

Patents