Microbial pretreatment of rice husk and groundnut shell for bioethanol production

Bacterial species were isolated from the rumen of ruminants to test for their ability to hydrolyse rice husks and groundnut shells. The isolates from the rumen were characterized and identified as Bacillus licheniformis, Bacillus lentus, Bacillus subtilis, Paenibacillus alvei, Yersinia enterocolitica as well as Salmonella sp. Similarly, Zymomonas mobilis and Saccharomyces cerevisiae were isolated from rotten oranges and palm wine to test for their ability to ferment the hydrolysates. The highest yield of reducing sugar of 4.1 % was obtained from groundnut shell. Rice husk yielded the lowest quantity of reducing sugar with a total yield of 2.96 %. The highest concentration of bioethanol of 0.96 % was produced using a combination of Saccharomyces cerevisiae and Zymomonas mobilis from groundnut shell. Also, the lowest concentration of 0.11 % of bioethanol was obtained when Zymomonas mobilis was used on hydrolysates from groundnut shells. The combination of Saccharomyces cerevisiae and Zymomonas mobilis yielded the highest ethanol when compared with the yields obtained when the organisms were used seperately. The result reveals the potentials of the fermentative organisms to produce ethanol from agrowastes.