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 (?) were  1192 min^?1, 1463 min^?1 and 1559 min^?1 and maximum sp. growth rate (? _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