Location: Bioenergy ResearchTitle: Influence of genetic background of engineered xylose-fermenting industrial Saccharomyces cerevisiae strains for ethanol production from lignocellulosic hydrolysates
|DIAS-LOPES, DAIANE - Federal University Of Rio Grande Do Sul|
|ROSA, CARLOS AUGUSTO - Federal University Of Minas Gerais|
|Hector, Ronald - Ron|
|AYUB, MARCO ANTONIO A - Federal University Of Rio Grande Do Sul|
Submitted to: Journal of Industrial Microbiology and Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/5/2017
Publication Date: 11/1/2017
Citation: Dias-Lopes, D., Rosa, C.A, Hector, R.E., Dien, B.S., Mertens, J.A., Ayub, M.A.Z. 2017. Influence of genetic background of engineered xylose-fermenting industrial Saccharomyces cerevisiae strains for ethanol production from lignocellulosic hydrolysates. Journal of Industrial Microbiology and Biotechnology. 44(11):1575-1588. doi: 10.1007/s10295-017-1979-z.
Interpretive Summary: Pretreatment of biomass is needed to release sugars for the production of fuels and chemicals using microorganisms. The pretreatment process also produces toxic side-products that inhibit fermentation. Industrial yeasts isolated from Brazilian bioethanol production facilities show enhanced tolerance to these inhibitory compounds. In this study, two yeast strains frequently used by Brazilian ethanol producers were evaluated for their ability to produce the biofuel ethanol from switchgrass. The strains were first engineered to express the genes required for metabolism of the five-carbon sugar, xylose. Xylose is the second most abundant sugar in nature and must be efficiently utilized for the process to be economically feasible. One of the engineered yeast strains was able ferment switchgrass hydrolysate containing a high concentration of inhibitory compounds efficiently to ethanol. This study will be of interest to cellulosic ethanol producers.
Technical Abstract: An industrial ethanol-producing Saccharomyces cerevisiae strain with genes needed for xylose-fermentation integrated into its genome was used to obtain haploids and diploid isogenic strains. The isogenic strains were more effective in metabolizing xylose than their parental strain (p < 0.05) and able to co-ferment glucose and xylose in the presence of high concentrations of inhibitors resulting from the hydrolysis of lignocellulosic biomass (switchgrass). The rate of xylose consumption did not appear to be affected by the ploidy of strains or the presence of two copies of the xylose-fermentation genes. However, inhibitor tolerance was influenced by the heterozygous genome of the industrial strain, which also showed a marked influenced on tolerance to increasing concentrations of toxic compounds, such as furfural. In this work, the genetic background was found to be important to develop efficient xylose-fermenting industrial yeast strains.