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59. Additional file 1 of Overexpression of mGDH in Gluconobacter oxydans to improve d-xylonic acid production from corn stover hydrolysate

Author

Mao, Xinlei, Zhang, Baoqi, Zhao, Chenxiu, Lin, Jinping, and Wei, Dongzhi

Abstract

Additional file 1: Table S1. Comparison of d-xylonic acid production by different organisms. Table S2. Strains, plasmids and primers used in this study. Figure S1. Comparison of d-xylonic acid production by different G. oxydans strains. The conversions were carried out in shake flasks at 30 ��C and 200 rpm. The reaction system contained 40 g/L d-xylose, 50 mM citric acid buffer (pH 5.8) and 1.90 gdcw/L resting cells. Figure S2. The activities of mGDHs from G. oxydans DSM2003 and G. oxydans/pBBR-R3510-mGDH toward xylose. Figure S3. Batch D-xylonic acid production from 535 g/L d-xylose by G. oxydans/pBBR-R3510-mGDH. The conversion was carried out in a 7 L fermenter with 4 vvm aeration, 30 ��C and 600 rpm conditions. The pH was maintained at 5.8 by using a 4 M NaOH solution. The reaction system contained 535 g/L d-xylose and 3.82 gdcw/L resting cells. Figure S4. Transformation of furfural and HMF by G. oxydans/pBBR-R3510-mGDH and G. oxydans DSM2003, respectively. (a) Transformation of furfural; (b) transformation of HMF. The conversions were carried out in shake flasks at 30 ��C and 200 rpm. The reaction system contained 0.5 or 2.5 g/L furfural (HMF), 40 g/L d-xylose, 50 mM citric acid buffer (pH 5.8), and 1.90 gdcw/L resting cells. Figure S5. The activities of the membrane-bound dehydrogenases of membrane fractions from G. oxydans DSM2003 and G. oxydans/pBBR-R3510-mGDH toward furfural and HMF.

Published
2022
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82. Design and engineering of whole‐cell biocatalyst for efficient synthesis of (R)‐citronellal.

Author

Zhang, Baoqi, Du, Han, Zheng, Yanqiu, Sun, Jiale, Shen, Yu, Lin, Jinping, and Wei, Dongzhi

Subjects
ENGINEERING design, MOLECULAR dynamics, ENZYMES, ESCHERICHIA coli, BACILLUS megaterium
Abstract

Summary: Bioproduction of optical pure (R)‐citronellal from (E/Z)‐citral at high substrate loading remains challenging. Low catalytic efficiency of (R)‐stereoselective ene reductases towards crude citral mixture is one of the major bottlenecks. Herein, a structure‐based engineering strategy was adopted to enhance the catalytic efficiency and stereoselectivity of an ene reductase (OYE2p) from Saccharomyces cerevisiae YJM1341 towards (E/Z)‐citral. On basis of homologous modelling, molecular docking analysis and alanine scanning at the binding pocket of OYE2p, a mutant Y84A was obtained with simultaneous increase in catalytic efficiency and stereoselectivity. Furthermore, site‐saturation mutagenesis of Y84 yielded seven mutants with improved activity and stereoselectivity in the (E/Z)‐citral reduction. Among them, the variant Y84V exhibited an 18.3% and 71.3% rise in catalytic efficiency (kcat/Km) for (Z)‐citral and (E)‐citral respectively. Meanwhile, the stereoselectivity of Y84V was improved from 89.2% to 98.0% in the reduction in (E/Z)‐citral. The docking analysis and molecular dynamics simulation of OYE2p and its variants revealed that the substitution Y84V enabled (E)‐citral and (Z)‐citral to bind with a smaller distance to the key hydrogen donors at a modified (R)‐selective binding mode. The variant Y84V was then co‐expressed with glucose dehydrogenase from Bacillus megaterium in E. coli D4, in which competing prim‐alcohol dehydrogenase genes were deleted to prevent the undesired reduction in the aldehyde moiety of citral and citronellal. Employing this biocatalyst, 106 g l−1 (E/Z)‐citral was completely converted into (R)‐citronellal with 95.4% ee value and a high space‐time yield of 121.6 g l−1 day−1. The work highlights the synthetic potential of Y84V, which enabled the highest productivity of (R)‐citronellal from (E/Z)‐citral in high enantiopurity so far. [ABSTRACT FROM AUTHOR]

Published
2022
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99. Assessing the stereoselectivity of carbonyl reductases toward the reduction of OPBE and docking analysis.

Author

Chen, Rong, Deng, Jian, Lin, Jinping, Yin, Xiaopu, Xie, Tian, Yang, Shengli, and Wei, Dongzhi

Subjects
CARBONYL compounds, CARBONYL reductase, STEREOSELECTIVE reactions, HYDROGEN transfer reactions, MOLECULAR docking
Abstract

The asymmetric reduction of prochiral carbonyl compounds by NAD(P)H-dependent carbonyl reductases represents a powerful method for the production of optically active alcohols. The stereoselectivity of a series of carbonyl reductases were evaluated toward the reduction of ethyl 2-oxo-4-phenylbutyrate (OPBE). A majority of reductases produced the ethyl ( R)-2-hydroxy-4-phenylbutyrate (( R)-HPBE) with low to excellent enantiomeric excess (e.e.), whereas about 30% reductases catalyzed OPBE to form ( S)-HPBE. Among them, the carbonyl reductase from Saccharomyces cerevisiae (SeCR) and short-chain dehydrogenase from Gluconobacter oxydans (GoKR) exhibited 100% e.e., yielding the corresponding ( R) and ( S)-HPBE, respectively. However, the SeCR showed relative higher activity (29.0 U/mg) and affinity ( Km of 0.22 mM) than those of GoKR. Docking analysis found that the interaction of OPBE with enzyme-NADPH complex determined the NADPH-provided hydrogen transfer and the configuration of reductive product. These results indicated that the three-dimensional (3D) structure of enzymes controlled the stereoselectivity of the reductive product based on the geometry of the substrate and cofactor. [ABSTRACT FROM AUTHOR]

Published
2016
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