FTIR Analysis and Optimization of Simultaneous Saccharification and Fermentation Parameters for Sustainable Production of Ethanol from Peels of Ananas cosmosus by Mucor indicus MTCC 4349

Abstract

The pulverized A. cosmosus peel was found to contain 25 ± 0.31 % cellulose, 28 ± 0.18 % hemicellulose and 8 ± 0.07 % of lignin on dry solid basis. 1 % H2SO4 delignified A. cosmosus peel yielded 38.81 % xylose, 29.31 % fructose and 18.89 % glucose under steam explosion, with a hydrolytic efficiency of 75.52 %. Fourier transform infrared spectroscopy results not only indicated the penetration of H2SO4 in the amorphous region of the biomass and degradation of hemicelluloses but also shows the structural differences before and after pretreatment. Simultaneous Saccharification and Fermentation of pretreated A. cosmosus peel by cellulase and Mucor indicus MTCC 4349 were investigated in the present study. Important process variables for ethanol production from pretreated A. cosmosus peel were optimized using Response Surface Methodology (RSM) based on central composite design (CCD) experiments. A three level CCD experiments with central and axial points was used to develop a statistical model for the optimization of process variables such as incubation temperature (30, 32 and 34 °C) X1, inoculum level (2, 4 and 6 %) X2 and nutrients (1/2/3) X3. Data obtained from RSM on ethanol production were subjected to the analysis of variance and analyzed using a second order polynomial equation and contour plots were used to study the interactions among three relevant variables of the fermentation process. The fermentation experiments were carried out at flask level. The processing parameters setup for reaching a maximum response for ethanol production was obtained when applying the optimum values for temperature (30 °C), inoculum level (2 %) and fermentation medium (urea, NaH2PO4, tryptone and meat extract) for Mucor indicus MTCC 4349. Maximum ethanol concentration 10.4293 g/l was obtained after 72 h from Mucor indicus MTCC 4349 at the optimized process conditions in aerobic batch fermentation.