5-20: Glycosyl hydrolase enzyme production from agricutural wastes by T. reesei

A variety of renewable fuels and chemicals can be made from lignocellulosic biomass.  Most of these processes are fermentations that require biomass to be converted to fermentable sugars.  One of the most expensive steps of lignocellulosic sugar production is the hydrolysis enzyme production.  Currently, glycosyl hydrolase enzymes are produced from simple purified substrates like crystalline cellulose.  This research investigates the potential for glycosyl hydrolase production from lignocellulose using Trichoderma reesei QM9414.  Using lignocellulosic susbtrates has two potential advantages.  Lignocellulose is cheaper than purified cellulose because it requires less processing and the enzyme may be more specific if it is produced using the same substrate that will be hydrolyzed for sugar production.  In this study, crystalline cellulose (Avicel), raw rice straw and alkaline pretreated rice straw were tested as carbon sources for enzyme induction by T. reesei. After 8 days of culture, the enzyme was harvested and the activity was quantified by measuring the glucose release from filter paper. Based on the glucose release, pretreated rice straw had the highest filter paper glucose release (0.36 g/L or 0.01 g/g) followed by raw rice straw (0.21 g/L or 0.006 g/g) and Avicel (0.16 g/L or 0.005 g/g). The enzyme was concentrated and compared to commercial cellulase enzymes in a hydrolysis reaction on pretreated rice straw.  Preliminary data suggests that at the same enzyme loading (FPU/g cellulose),  the total reducing sugar released by the enzyme produced with pretreated rice straw is comparable to that by commercial cellulase enzymes.