Lignocellulosic xylitol production from corncob using engineered Kluyveromyces marxianus

Jia Zhang; Teng Xu; Xiaohang Wang; Xiaoyan Jing; Jia Zhang; Jiong Hong; Jian Xu; Jichao Wang

doi:10.3389/fbioe.2022.1029203

Lignocellulosic xylitol production from corncob using engineered Kluyveromyces marxianus

Front Bioeng Biotechnol. 2022 Oct 21:10:1029203. doi: 10.3389/fbioe.2022.1029203. eCollection 2022.

Authors

Jia Zhang^{1

2

3

4}, Teng Xu^{1

3}, Xiaohang Wang^{1

2

3}, Xiaoyan Jing^{1

2

3}, Jia Zhang⁴, Jiong Hong^{5

6}, Jian Xu^{1

2

3}, Jichao Wang⁴

Affiliations

¹ Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China.
² Laboratory of Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.
³ University of Chinese Academy of Sciences, Beijing, China.
⁴ State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China.
⁵ School of Life Sciences, University of Science and Technology of China, Hefei, China.
⁶ Hefei National Laboratory for Physical Science at the Microscale, Hefei, China.

Abstract

Xylitol production from lignocellulose hydrolysate is a sustainable and environment-friendly process. In this study, a systematic process of converting corncob waste into xylitol is described. First, the corncobs are hydrolyzed with acid to a hydrolysate. Second, Kluyveromyces marxianus YZJQ016 derived from K. marxianus YZJ074, constructed by overexpressing ScGAL2-N376F from Saccharomyces cerevisiae, CtXYL1 from Candida tropicalis, and KmZWF1 from K. marxianus, produces xylitol from the hydrolysate. A total of ten xylose reductase genes were evaluated, and CtXYL1 proved best by showing the highest catalytic activity under the control of the KmGAPDH promoter. A 5 L fermenter at 42°C produced 105.22 g/L xylitol using K. marxianus YZJQ016-the highest production reported to date from corncob hydrolysate. Finally, for crystallization of the xylitol, the best conditions were 50% (v/v) methanol as an antisolvent, at 25°C, with purity and yield of 99%-100% and 74%, respectively-the highest yield reported to date.

Keywords: Kluyveromyces marxianus; corncob hydrolysate; crystallization; xylitol; xylose reductase.