Evolutionary Adaptation of Fermenting Strains in Wheat Straw Hydrolysate for Bioethanol and Lactic Acid Production
Evolutionary Adaptation of Fermenting Strains in Wheat Straw Hydrolysate for Bioethanol and Lactic Acid Production
Imrana Khushk1, Abdul Nabi Jatt2, Abdul Sattar Qureshi1*, Choudhary Haider Ali3, Muhammad Aqeel Bhutto1, Imran Ibrahim Khaskheli1, Sartar Iqbal Panhwer1
ABSTRACT
Cellulosic biorefinery facing two major difficulties namely (pretreatment inhibitors and cost of cellulase enzyme). In the present study, long term evolutionary adaptation was evaluated for ethanol and lactic acid production to overcome the pretreatment inhibitors issue. Saccharomyces cerevisiae Angel was used for the production of ethanol, while, Bacillus coagulans, Pediococcus sp. and Lactobacillus sp. were used for lactic production, respectively. All the microbial strains were inoculated on wheat straw hydrolysate and were monitored with regular interval until stable cell growth, glucose consumption, and, ethanol and lactic acid production. Fermentation performance of the adapted strain improved over parental strains. Ethanol and lactic acid yield reached to 90% and 75%, respectively, when using freshly pretreated wheat straw or wheat straw hydrolysate or rice straw as carbon source. On-site produced cellulase from Bacillus subtilis OCS SH-2 was applied in the saccharification of pretreated wheat straw and rice straw. There was no significant difference when commercial cellulase youtell#7 and onsite produced cellulase were used in saccharification of high solid wheat straw simultaneous saccharification and fermentation (SSF). However, onsite produced cellulase does not need enzyme purification, packing and transportation. Hence, the production of bioethanol and lactic acid cost reduced at large extent by using on-site produced cellulase in the saccharification of lignocellulosic material.
Novelty Statement | In house cellulase production saved enzyme production, purification, and transportation cost. Evolutionary adapted strain produced higher ethanol and lactic acid titer from wheat straw. Adaptation of the fermenting strains reduce fermentation time and enhance the product yield
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June 2021
Vol. 36, Iss. 1, pp. 1-123
