Evaluation of Saccharomyces cerevisiae Improved Strains Potential in the Bioethanol Production from Bagasse

Abstract

Plant biomass can be utilized to produce bioethanol, because they are abundantly available in nature. The cost of ethanol production from lignocellulosic materials is relatively high with low yield. But this can be solved by strain improvement processes. This study is aimed at evaluate bioethanol production potential of improved strains of Saccharomyces cerevisiae developed through random mutagenesis. Bagasse was hydrolysed with 1% NaOH and 1.0M H2SO4 respectively for five days. The hydrolysed bagasse was saccharified using Aspergillus niger isolated from soil samples. Saccharomyces cerevisiae isolated from locally produced wines; sorghum (burukutu) oil palm wine (emu) and raphia palm wine (oguro) with the highest ethanol production (5.0g/ml) were used, and then treated with physical mutagen (ultraviolet light) and chemical mutagens (Acridine dye, Bromo acetaldehyde, dithiothreitol, Ketoconazole and Nitrous acid) respectively to develop mutant with high ethanol producing efficiency under varied operational parameters. Three mutant strains of Saccharomyces cerevisiae namely;- SUV, SCD and SCK produced higher volumes of ethanol (7.5 g/ml, 9.8 g/ml, 11.2 g/ml respectively). SCD and SCK were able to grow at 25% ethanol concentration indicating that they had higher ethanol tolerance ability than the other strains. The optimum temperature and pH for ethanol production by all the strains were 350C and 6.0 respectively. The improved strains of Saccharomyces cerevisiae developed through random mutation techniques had produced more ethanol from the bagasse than the wild-type.