Microbial enzyme systems for biomass conversion: emerging paradigms

The contemporary relevance of biofuels as an attractive replacement for liquid fossil fuels has rekindled global interest in the conversion of cellulosic biomass - the most abundant renewable source of carbon and energy on our planet. In order to achieve efficient systems for such a formidable substrate, we take guidance from the native enzyme systems of the microbes that have evolved to rid the natural environment of plant-derived wastes. These cellulolytic bacteria and fungi employ a diversity of contrasting but complementary mechanisms for the hydrolysis of cellulose and other related complex plant cell wall polysaccharides. This review covers various known microbial approaches for attacking the recalcitrance problem in the conversion of cellulosic biomass to soluble sugars en route to a biofuels-based society.