Muhammad Nauman Aftab and Asma Zafar
Institute of Industrial Biotechnology, Government College University, Lahore, Pakistan
The present work is aimed to evaluate the saccharification potential of hemicellulases (β-xylosidase and xylanase) cloned by using Bacillus licheniformis ATCC 14580 into E. coli BL21 and plant biomass for the production of bioethanol. Effect of various parameters on enzyme production was examined in a fermenter. Xylanase production was maximum while maintaining the fermenter volume at 70%, rate of agitation at 200 rpm, air supply at 2.0 vvm, dissolved oxygen at 20%, inoculum concentration of 3%, at 37°C and a pH of 7.0 while for β-xylosidase optimized condition for best enzyme production were 2.5 vvm aeration rate, with 2% inoculum size, 200 rpm agitation rate, 25% dissolved oxygen, at 37ºC with initial pH of medium 7.5 and 70% media volume. Saccharification ability of these enzymes were optimized one by one as well as collectively by studying different parameters. Among different biomass tested, maximum saccharification percentage was observed when both hemicellulose enzymes were used at same time, with 8% sugarcane bagass at 50°C and 120 rpm after 6 hours of incubation with twenty units of each enzyme. The results suggested that bioconversion of hemicellulases into simple sugars can be utilized for biofuel production.