고자경 (한국과학기술연구원)

구.농수식품

조회973

고자경Ja Kyong Ko

한국과학기술연구원

GCB Bioenergy, First published: 10 October 2019 | https://doi.org/10.1111/gcbb.12656 Improved bioconversion of lignocellulosic biomass by Saccharomyces cerevisiae engineered for tolerance to acetic acid

Abstract

Ja Kyong Ko^a, Tseveendorj Enkh-Amgalan^a,b, Gyeongtaek Gong^a, Youngsoon Um^a,b,c, and Sun-Mi Lee^a,b,c,*

^aClean Energy Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea^b Clean Energy and Chemical Engineering, University of Science and Technology, Daejeon 34113, Republic of Korea ^c Green School (Graduate School of Energy and Environment), Korea University, Seoul 02841, Republic of Korea

^* Corresponding author : Sun-Mi Lee

Abstract
Lignocellulosic biomass has considerable potential for the production of fuels and chemicals as a promising alternative to conventional fossil fuels. However, the bioconversion of lignocellulosic biomass to desired products must be improved to reach economic viability. One of the main technical hurdles is the presence of inhibitors in biomass hydrolysates, which hampers the bioconversion efficiency by biorefinery microbial platforms such as Saccharomyces cerevisiae in terms of both production yields and rates. In particular, acetic acid, a major inhibitor derived from lignocellulosic biomass, severely restrains the performance of engineered xylose‐utilizing S. cerevisiae strains, resulting in decreased cell growth, xylose utilization rate, and product yield. In this study, the robustness of XUSE, one of the best xylose‐utilizing strains, was improved for the efficient conversion of lignocellulosic biomass into bioethanol under the inhibitory condition of acetic acid stress. Through adaptive laboratory evolution, we successfully developed the evolved strain XUSAE57, which efficiently converted xylose to ethanol with high yields of 0.43–0.50 g ethanol/g xylose even under 2–5 g/L of acetic stress. XUSAE57 not only achieved 2‐fold higher ethanol yields but also improved the xylose utilization rate by more than 2‐fold compared to those of XUSE in the presence of 4 g/L of acetic acid. During fermentation of lignocellulosic hydrolysate, XUSAE57 simultaneously converted glucose and xylose with the highest ethanol yield reported to date (0.49 g ethanol/g sugars). This study demonstrates that the bioconversion of lignocellulosic biomass by an engineered strain could be significantly improved through adaptive laboratory evolution for acetate tolerance, which could help realize the development of an economically feasible lignocellulosic biorefinery to produce fuels and chemicals.

Keywords : acetic acid, bioethanol, lignocellulosic biomass, lignocellulosic hydrolysate, Saccharomyces cerevisiae, xylose

논문정보

형식Research article
게재일2019년 10월 (BRIC 등록일 2019-10-30)
연구진국내 연구진
분야
구분구・농수식품

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