Metagenomcs for Obtaining Novel Biomass Degradation Enzymes for Biofuel Production

One of the bottlenecks in the production of cellulose ethanol from lignocellulosic biomass is the saccharification step, where the cellulose from the biomass is broken down into simple sugars which can then be fermented to ethanol. Cellulose is a long chain of glucose molecules which are connected together by what is known as "glycosidic bonds". Enzymes which have "glycosyl hydrolase" (GHase) activities are said to be potentially useful for degradation of cellulosic biomass for biofuel production. Enzymes with high biomass degradation activities are often "discovered" by microbial screening programs, involving the cultivation of microorganisms in the laboratory. An emerging field, known as "metagenomics", stands as an alternative strategy for the discovery of biomass degradation enzymes without the need for direct cultivation of the microorganism.

Using molecular biology techniques, DNA from microbial communities (for example, in soil samples), is obtained and investigated for genes that encode enzymes for biomass degradation. A recent article by Luen-Luen Li and associates from the Brookhaven National Laboratory (United States) reviews "metagenomic approaches to mining complex microbial communities (comprising both non-cultivable and cultivable microorganisms) for biofuel production". One of their review findings mentioned that metagenomes (genetic material from an environmental sample) from microbial communities derived from termite guts displayed "more putative glycosyl hydrolase (GHase) homologues compared to other samples, such as human oral microflora. The complete review can be accessed in the online open journal, Biotechology for Biofuels (URL above).

Related information on metagenomics http://dels.nas.edu/metagenomics/overview.shtml