S. Sivanarutselvi, P. Poornima, K.
Muthukumar and M. Velan*
Department of Chemical Engineering,
Alagappa College of Technology, Anna University, Chennai-600 025, India
*Corresponding Author Email :
Aim: In this study,
effectiveness of alkali pretreatment of banana pseudostem for the production
of biobutanol by fermentation using Clostridium sporogenes under
strict anaerobic conditions was studied.
Methodology: Banana pseudostem
was pretreated by alkali soaking at constant temperature (30, 50 and 70?C)
and concentration of 0.25 to 2% (w/v) at solid to liquid ratio of 1:10 for 24
hr to depolymerize the lignocellulosic biomass. Further to increase
delignification, the alkali soaked samples were subjected to thermal
treatment at 121?C for 15 min. The hydrolysates were subjected to
acetone-butanol-ethanol fermentation using Clostridium sporogenes to
delignification of 92% was obtained at 30?C soaking temperature
with 2% NaOH (w/v). Increase in temperature led to increase in
delignification but also resulted in reduced recovery of cellulose. Maximum
glucose yield of 524 mg g-1 glucan was obtained from the
pretreated biomass. Fermentation of hydrolysate obtained from alkali soaking
pretreatment by C. sporogenes under anaerobic condition resulted in 10.12 g l-1
of butanol with a yield of 0.326 g g-1 of total sugar consumed and
it was much higher compared to untreated biomass.
Interpretation: Alkali soaking
pretreatment at 30?C and alkali concentration of 1.5% (w/v) was
effective to depolymerize the biomass to obtain maximum sugar and butanol
yield from banana pseudostem. Thermal treatment was not effective in
increasing the production of butanol due to pseudo lignin formation and
presence of inhibitors.
Key words: Alkali pretreatment, Banana pseudostem, Biobutanol, Clostridium
sporogenes, Enzymatic hydrolysis
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