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, 50oC; 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 (m) were 5.30 s −1 , 5.54 s −1 , and 5.93 s −1 and maximum sp. growth rate (m 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 (K s ) 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 (K m ) 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. DOI: http://dx.doi.org/10.3329/cerb.v16i1.6659 Chemical Engineering Research Bulletin 16(2013) 33-44