Bioethanol production from Miscanthus using thermotolerant Saccharomyces cerevisiae mbc 2 isolated from the respiration-deficient mutants. (August 2015)

• Record Type: Journal Article
• Authors: Cha, Young-Lok; An, Gi Hong; Yang, Jungwoo; Moon, Youn-Ho; Yu, Gyeong-Dan; Ahn, Jong-Woong
• Is Part Of: Renewable energy. Volume 80(2015)
• Page Start: 259
• Page End: 265
• Publication Date: 2015-08
• Subjects: Bioethanol -- Respiratory deficient mutant -- Thermotolerant yeast -- Pretreatment -- SSF; Renewable energy sources -- Periodicals; Power resources -- Periodicals; Énergies renouvelables -- Périodiques; Ressources énergétiques -- Périodiques; 333.794
• DOI: 10.1016/j.renene.2015.02.016
• Languages: English
• ISSNs: 0960-1481

Abstract

Abstract: One major obstacle of simultaneous saccharification and fermentation (SSF) is that enzymatic hydrolysis in SSF is conducted at non-optimal temperature. To break through this bottleneck, thermotolerant Saccharomyces cerevisiae strains mbc 1-4 were screened by spot-assay from respiration-deficient mutants induced by ethidium bromide. When four strains placed in liquid medium, the strains exhibited significant increased growth and fermentability at 42 °C in comparison to the host. Consequently, S. cerevisiae mbc 2 was selected to be the most suitable for bioethanol production at 42 °C. Miscanthus was pretreated with 1.5 M NaOH at 150 °C for 30 min in 1 L-vessel. As a result, 42.6% of solids containing 77.9% cellulose were recovered. Next, SSF was conducted with pretreated Miscanthus containing 3% glucan to estimate the fermentability of S. cerevisiae mbc 2 at 42 °C. In results, Ethanol concentration and theoretical ethanol yield by S. cerevisiae mbc 2 in 48 h were 15.3 g/L and 90.1%, respectively, whereas those by the control were 8.3 g/L and 49.3%, respectively. In addition, SSF with increased substrate concentration upto 9% glucan resulted in 86.3% and 82.2% of theoretical ethanol yield, respectively. Thus, our approach for SSF with high solid loading using thermotolerant S. cerevisiae mbc 2 contributes to process and microbial strain development for bioethanol production. Highlights: Novel thermotolerant yeast strains were induced and isolated by random mutagenesis using EtBr. The thermotolerant strains were verified to grow and ferment better than its control at 42 °C. The selected strain mbc 2 was verified to be suitable for SSF of pretreated Miscanthus at 42 °C. Furthermore, the selected strain mbc 2 was proven to be suitable for SSF with high solids loading of Miscanthus. (e.g., 9% glucan).