Bioethanol fermentation from non-treated and pretreated corn stover using aspergillus oryzae

Abstract

A comparison was studied for non-treated and pretreated corn stover with dilute alkaline peroxide and dilute acid treatment respectively for bioethanol production by simultaneous saccharification and fermentation (SSF) process in a continuous stirred batch bioreactor using fungi Aspergillus oryzae. The optimum parameters for bioethanol fermentation were: time, 48 h; pH, 6.0; temperature, 50°C; stirring speed, 35 rpm; and corn stover loading, 35 g/L. The maximum concentration of bioethanol at optimum fermentation process parameters were 0.762 g/g, 0.799 g/g and 0.819 g/g for non-treated, dilute acid and dilute alkaline peroxide pretreated corn stover respectively. Maximum yields of bioethanol were 0.399 g/L.h, 0.420 g/L.h and 0.431 g/L.h of corn stover at optimum parameters for non-treated, dilute acid and dilute alkaline peroxide pretreated corn stover respectively. The sp. growth rate (μ) were 5.30 s-1, 5.54 s-1, and 5.93 s-1 and maximum sp. growth rate (μ max) were 10.60 s-1, 11.08 s-1 and 11.86 s-1 using Monod model for non-treated, dilute acid and dilute alkaline peroxide pretreated corn stover respectively. The Monod parameter (Ks) were 33.87 g/L, 34.21 g/L and 34.85 g/L for non-treated, dilute acid and dilute alkaline peroxide pretreated corn stover respectively. The sp. enzyme activity (ν) were 1192 min-1, 1463 min-1 and 1559 min-1 and maximum sp. growth rate (ν max) were 2384 min-1, 2926 min-1 and 3118 min-1 using Michaelis-Menten enzyme kinetic model for non-treated, dilute acid and dilute alkaline peroxide pretreated corn stover respectively. The Michaelis-Menten parameter (Km) were 34.42 g/L, 34.63 g/L and 34.85 g/L for non-treated, dilute acid and dilute alkaline peroxide pretreated corn stover respectively. The first order rate constants (k) were 0.014 h-1, 0.016 h-1 and 0.019 h-1 for non-treated, dilute acid and dilute alkaline peroxide pretreated corn stover for continuous stirred batch bioreactor respectively. © Bangladesh Uni. of Engg. & Tech.