Asian Journal of Microbiology, Biotechnology & Environmental Sciences Paper

ALKALINE DELIGNIFICATION AND BIOETHANOL PRODUCTION FROM AGRO-RESIDUES

RAGHAVENDRA B. HAVANNAVAR AND G. S. GEETA

Abstract

Bioethanol is produced by fermentation of sugarcane molasses using strains of Saccharomyces cereviseae. But recent increase in cost of molasses, it has been emphasized to search alternate substrates for ethanol production. The agroresidues such as paddy straw, wheat straw and sugarcane bagasse as an alternate source for ethanol production were tested. In the present study, pretreatment process was developed for hydrolyzing paddy straw, wheat straw and sugarcane bagasse into fermentable sugars. The powdered substrates were pretreated with 2 and 3 per cent sodium hydroxide (NaOH) for different incubation periods. The substrate pretreated with 3 per cent NaOH for 8 h has given maximum cellulose content in sugarcane bagasse 0.695 g/g followed by wheat substrates were subjected for commercial cellulase enzyme pretreatment for further saccharification. The highest reducing sugar was recorded in sugarcane bagasse (136.86 mg/g), which was found significantly superior over other substrates. The hydrolysate thus obtained was used for screening of yeast cultures. Among yeast strains Pouhysolen tannophilus NCIM 3445 has showed comparatively higher ethanol yield in all the substrates.