Bioethanol production from apple pomace using co-cultures with saccharomyces cerevisiae in solid-state fermentation

Abstract

The objective of this study was isolation and screening of apple pomace utilizing microorganisms from soil which can be used as co-culture with S. cerevisiae for production of bioethanol. In this study, fifteen microorganisms were isolated from soil near the dumping site of apple pomace at HPMC, Parwanoo, H.P. on medium enriched with apple pomace. These isolates were assigned codes APW 1-15 and were screened for their potential to produce cellulase, xylanase and ethanol. The selected isolates were used as co-culture with S. cerevisiae for bioethanol production. All the isolates exhibited cellulase and xylanase activities ranging from 228.2 to 502.5 U/mL/min and 185.3 to 1010.7 U/mL/min respectively, but only three isolates (APW-02, APW-04 and APW-12) produced ethanol. Isolate APW-13 exhibited highest cellulase activity (502.5 U/mL/min), APW-04 showed highest xylanase activity (1010.7 U/mL/min) and APW-12 produced highest amount of ethanol (36 g/L). Two isolates (APW-12 and APW-13) were selected to co-culture with S. cerevisiae in solid-state fermentation of apple pomace for ethanol production. S. cerevisiae and isolate APW-12 co-culture fermentation resulted in higher ethanol production (49.64 g/L) than S. cerevisiae and APW-13 co-culture fermentation (41.7 g/L) while, S. cerevisiae alone produced 37.6 g/L ethanol. Isolate APW-12 and APW-13 belonged to genera Actinomyces and Bacillus respectively.