Ethanol production by Aspergillus niger US4MTCC9931 and Saccharomyces cerevisiae MTCC174 using different lignocellulosic biomass feed stocks

Abstract

To investigate the production of cellulases and hemicellulases from Aspergillus niger MTCC9931, solid state fermentation (SSF) was performed using 10 different lignocellulosic materials derived from agrowastes, i.e., rice straw, rice husk, wheat straw, corn cob, sugar cane bagasse, saw dust, banana stalk, Eichhornia, Parthenium stalk, and residual fruit pulp. Among these agrowastes, the maximum yield of reducing sugars (116.46 ± 2.56 g/mL) was observed with residual fruit pulp. Further, the same substrate showed the highest endoglucanase (389.1 ± 0.44 IU/g), MCC-adsorbable endoglucanase (3.4 ± 0.14 IU/g), cellulase (12.0 ± 0.13 IU/g), and FPase (4.9 ± 0.64 IU/g) activities. Sawdust showed the maximum xylanase activity (7478.0 ± 6.51 IU/g), and corncob showed maximum β-glucosidase activity (79.87 ± 1.15 IU/g). The maximum activities of all enzymes were observed at 72 h of SSF under shaking conditions. A. niger MTCC9931 can be concluded to be an important strain for potential applications in saccharification. The enzymatic hydrolysates of the agrowastes were used as substrates for ethanol production by Saccharomyces cerevisiae MTCC174. The maximum yield (35.34 g/L) of ethanol was obtained when residual fruit pulp was used as a substrate. This study has further demonstrated the feasible biotechnological conversion of agrowastes to produce ethanol using both A. niger and S. cerevisiae.