Bioethanol Production Optimization from KOH-Pretreated Bombax ceiba Using Saccharomyces cerevisiae through Response Surface Methodology

Abstract

The present study was based on the production of bioethanol from alkali-pretreated seed pods of Bombax ceiba. Pretreatment is necessary to properly utilize seed pods for bioethanol production via fermentation. This process assures the accessibility of cellulase to the cellulose found in seedpods by removing lignin. Untreated, KOH-pretreated, and KOH-steam-pretreated substrates were characterized for morphological, thermal, and chemical changes by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). Hydrolysis of biomass was performed using both commercial and indigenous cellulase. Two different fermentation approaches were used, i.e., separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF). Findings of the study show that the maximum saccharification (58.6% after 24 h) and highest ethanol titer (57.34 g/L after 96 h) were observed in the KOH-steam-treated substrate in SSF. This SSF using the KOH-steam-treated substrate was further optimized for physical and nutritional parameters by one factor at a time (OFAT) and central composite design (CCD). The optimum fermentation parameters for maximum ethanol production (72.0 g/L) were 0.25 g/L yeast extract, 0.1 g/L K2HPO4, 0.25 g/L (NH4)2SO4, 0.09 g/L MgSO4, 8% substrate, 40 IU/g commercial cellulase, 1% Saccharomyces cerevisiae inoculum, and pH 5.

A panoramic view of technological landscape for bioethanol production from various generations of feedstocks

“…At a high dose of Cu 2+ , Zn 2+ , the growth of S. cerevisiae was completely suppressed. Ghazanfar et al [ 149 ] optimized the physical and nutritional parameters by one factorial at a time (OFAT) and central composite design (CCD), respectively. The study reported that 0.25 g/L yeast extract, 0.25 g/L (NH4) 2 SO 4 , 0.1 g/L K 2 HPO 4 , 0.09 g/L MgSO 4 , 8% substrate, 40 IU/g commercial cellulase, 1% S.cerevisiae inoculum, and pH 5 are optimum for maximum ethanol production (72 g/l) from alkali pretreated Bombax ceiba .…”

Purifying Crude Glycerol from Biodiesel Production for Sustainable Energy Solutions

“…Various microorganisms from fungi and bacteria can be used to convert sugars into ethanol. Saccharomyces cerevisiae (yeast) is the most commonly used fungus [90], [91], while bacteria that can be used include Zymomonas mobilis, Escherichia coli (E. coli), and Kluyveromyces spp [44], [46], [92]. Then, ethanol as the fermentation product can be separated and purified through the distillation process [52].…”

Biofuels Production and Processing Technology

“…KOH-pretreated seed pods of Bombax ceiba for ethanol by S. cerevisiae in SSF and SHF were used as second-generation feedstock by Ghazanfar et al [29]. The study shows that the SSF process allows the maximum saccharification (58.6% after 24 h) and highest ethanol yield (57.34 g/L after 96 h) to be obtained.…”

“…The SSF process was optimized for physical and nutritional parameters by one factor at a time (OFAT) and central composite design (CCD), allowing to set the optimum fermentation parameters for highest ethanol production (72.0 g/L): 0.25 g/L yeast extract, 0.1 g/L K 2 HPO 4 , 0.25 g/L (NH 4 ) 2 SO 4 , 0.09 g/L MgSO 4 , 8% substrate, 40 IU/g commercial cellulase, 1% Saccharomyces cerevisiae inoculum, pH 5. This study proposed an inexpensive and novel source as a promising feedstock for pilot-scale second-generation bioethanol production [29].…”