Efficient l-lactic acid production from corncob residue using metabolically engineered thermo-tolerant yeast

[Display omitted] •An efficient l-lactic acid (l-LA) production yeast strain was constructed.•Glucose and xylose were simultaneously consumed in l-LA production.•No accumulation of xylitol via co-fermentation of glucose and xylose.•103.00 g/L l-LA was produced through corncob SSCF with economical ni...

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Bibliographic Details
Published in:Bioresource technology 2019-02, Vol.273, p.220-230
Main Authors: Kong, Xin, Zhang, Biao, Hua, Yan, Zhu, Yelin, Li, Wenjie, Wang, Dongmei, Hong, Jiong
Format: Article
Language:English
Subjects:
Alkali-pretreated corncob
Fermentation
Kluyveromyces marxianus
l-Lactic acid
Lactate Dehydrogenases - metabolism
Lactic Acid - biosynthesis
Lignin - metabolism
Metabolic Engineering
Saccharomyces cerevisiae - metabolism
SSCF
Zea mays - metabolism
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Summary:[Display omitted] •An efficient l-lactic acid (l-LA) production yeast strain was constructed.•Glucose and xylose were simultaneously consumed in l-LA production.•No accumulation of xylitol via co-fermentation of glucose and xylose.•103.00 g/L l-LA was produced through corncob SSCF with economical nitrogen source.•The optical purity of produced l-LA was 99.5%. Lactic acid is an important industrial product and the production from inexpensive and renewable lignocellulose can reduce the cost and environmental pollution. In this study, a Kluyveromyces marxianus strain which produced lactic acid efficiently from corncob was constructed. Firstly, two of six different lactate dehydrogenases, which from Plasmodium falciparum and Bacillus subtilis, respectively, were proved to be effective for l-lactic acid production. Then, five single genetic modifications were conducted. The overexpression of Saccharomyces cerevisiae proton-coupled monocarboxylate transporter, K. marxianus 6-phosphofructokinase, or disruption of K. marxianus putative d-lactate dehydrogenase enhanced the l-lactic acid accumulation. Finally, the strain YKX071, obtained via combination of above effective genetic engineering, produced 103.00 g/L l-lactic acid at 42 °C with optical purity of 99.5% from corncob residue via simultaneous saccharification and co-fermentation. This study first developed an effective platform for high optical purity l-lactic acid production from lignocellulose using yeast with inexpensive nitrogen sources.
ISSN:0960-8524
1873-2976
DOI:10.1016/j.biortech.2018.11.018