Enhanced bioethanol production from wheat straw hemicellulose by mutant strains of pentose fermenting organisms Pichia stipitis and Candida shehatae.

The main aim of the present study was to mutate yeast strains, Pichia stipitis NCIM 3498 and Candida shehatae NCIM 3501 and assess the mutant's ability to utilize, ferment wheat straw hemicellulose with enhanced ethanol yield. The organisms were subjected to random mutagenesis using physical (ultraviolet radiation) and chemical (ethidium bromide) mutagens. The mutant and wild strains were used to ferment the hemicellulosic hydrolysates of wheat straw obtained by 2 % dilute sulphuric acid and enzymatic hydrolysis by crude xylanase separately.

Bioconversion of lignocellulosic biomass to xylitol: An overview.

Lignocellulosic wastes include agricultural and forest residues which are most promising alternative energy sources and serve as potential low cost raw materials that can be exploited to produce xylitol. The strong physical and chemical construction of lignocelluloses is a major constraint for the recovery of xylose. The large scale production of xylitol is attained by nickel catalyzed chemical process that is based on xylose hydrogenation, that requires purified xylose as raw substrate and the process requires high temperature and pressure that remains to be cost intensive and energy consuming.