Discovery and design of novel enzymes and enzyme systems for biofuels. In our effort to develop cost effective process to produce second generation biofuels, we are isolating novel enzymes with higher specificities towards cellulosic biomass. We have identified novel cellulase and xylanase enzymes from bacteria isolated from mid-gut of insects living on agricultural biomass and overexpressed them in E. coli for use in saccharification process. Based on structural modelling, we have synthesized two chimeric bifuctional enzymes, one with the fusion between endocellulase and xylanase and second with the fusion between endocellulase and beta-glucosidase. Both these bifuctional enzymes were shown to be equal or more effective than their individual counterparts. We are now developing metagenomic, metatranscriptomic and metaproteomic techniques to identify new cellulolytic enzymes from gut microbes.
Engineering bacteria to produce biofuel. We are working on production of bioethanol from pre-treated lignocellulosic biomass with the help of metabolic engineering and system biology approaches to bring down costs. We are secreting various cellulytic enzymes in E. coli to enable it to utilize pretreated lignocellulosic biomass. In order to produce high level of ethanol using metabolic engineering tools, we are engineering E. coli to enhance bioethanol yield by blocking side pathways that produce competing co-products and by providing an alternate pathway that can fulfil NADH requirement for homo-ethanol production. By optimizing the expression of native pathway and without using any foreign gene, we show production of ethanol with high yield and productivity. In addition, we have identified few natural bacteria from guts of insect (living on plants) that degrade lignocellulosic biomass with high efficiency and are exploring the possibility of engineering these bacteria to produce bioethanol from lignocellulosic biomass. The development of an integrated biocatalyst that can perform both functions, i.e., conversion of complex cellulose and hemicellulose into monomeric sugar molecules and fermentation of monomeric sugar into biothanol, is likely to bring down the production cost of lignocellulosic ethanol considerably. We are also engineering laboratory bacteria that can produce butanol and alkane/alkene from agricultural biomass.
Engineering Algae to produce biofuel. We are working on algal technology and improving biomass and neutral lipid content in algae cells through synthetic and system biology approach.