Fungal Isolates from Local Environment: Isolation, Screening and Application for the Production of Ethanol from Water Hyacinth

Water hyacinth biomass is a potential substrate for the production of ethanol which can be conveniently used as a gasoline additive as an octane booster and improve the vehicle emissions. The present study is focused on isolating and screening indigenous fungi for the hydrolysis of water hyacinth in the lignocellulosic conversion process. The initial cellulose activity was measured as ICMC (carboxymethyl cellulose) index which was found to be max at pH=5. Crude enzymes extracted after solid state fermentation (SSF) in an effort to reduce the cost of ethanol production, which needs lesser infrastructure and relatively less skilled manpower besides being able to use cheaper raw materials for enzyme production. The cellulytic and xylanytic activity was monitored using water hyacinth as substrate. Out of several isolates screened, best result was recorded up to 131.995 mg/g of reducing sugar and xylose yield up to 210.4 mg/g of WHB. Concentrated enzymatic hydrolysate of WHB containing reducing sugars and xylose was used for ethanol fermentation. The maximal ethanol yield was 2.217 g/l using Pichia stipitis, 2.163 g/l using Candida shehatae and 1.925 g/l using Saccharomyces cerevisae. Fungal isolate F6 provided the best yield as well as total extracellular enzyme production in comparison to other fungal strains, so identification of the fungal sample to its nearest species was undertaken. Fungal strain F6 (Alternaria alternate) was sequenced and the genomic DNA information was submitted to gene bank NCBI and an unique accession no JQ781696 was assigned.