Fourier Transform Infrared Mapping of Peels of Citrus sinensis var mosambi after Physiochemical Pretreatment and its SSF for Ethanol Production by Saccharomyces cerevisiae MTCC 3821- An Economic&Ecological Venture

Pulverized peels of Citrus sinensis var mosambi consists of 32 0.36 % cellulose, 25 0.18 % hemicellulose and 18 0.08 % of lignin on dry solid (DS) basis.1 % NaOH delignified peels of C. sinensis var mosambi yielded 4.98 % glucose, 4.46 % raffinose and 7.67 % fructose under steam explosion, with a hydrolytic efficiency of 90.32 0.55 %. Fourier transform infrared spectroscopy results indicated the penetration of NaOH in the amorphous region of the biomass and degradation of hemicelluloses The enzymes required for hydrolysis were prepared from culture supernatants of Trichoderma reesei NCIM 1052 using wheat bran as carbon source under submerged fermentation conditions. Enzyme activity (U/ml) of crude cellulase produced by T. reesei NCIM 1052 was 311.1 mole/ml/min. Delignified C. sinensis var mosambi peel yielded 40.51 0.42 g/l glucose when enzymatically hydrolysed by crude cellulase at the substrate enzyme ratio of 1: 5. Simultaneous Saccharification and Fermentation (SSF) of peels of C. sinensis var mosambi by crude cellulase and entrapped Saccharomyces cerevisiae MTCC 3821 cells in calcium alginate beads were also investigated in the present study. Important process variables for ethanol production from pretreated peels of C. sinensis var mosambi 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 (30C, 32C and 34C) 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 (ANOVA) 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 (30C), inoculum level (6 %) and fermentation medium (ammonium sulphate, KH2PO4, peptone and yeast extract) for Saccharomyces cerevisiae MTCC 3821. Maximum ethanol concentration 9.94 g/l was obtained after 72 hours from Saccharomyces cerevisiae MTCC 3821 at the optimized process conditions in anaerobic batch fermentation.