Abstract
An Escherichia coli host microorganism was used for the production of the aldoxime dehydratase from Rhodococcus sp. YH3-3 (OxdYH3-3), which showed good activity toward aromatic aldoximes. Biotransformation of aromatic aldoximes to nitriles was studied using this recombinant biocatalyst OxdYH3-3, exemplified in particular for the synthesis of biorenewable-based 2-furonitrile. The gene encoding for the enzyme OxdYH3-3 was cloned to a histidine tag-containing overexpression vector pET15b, pET22b and pET28b and transformed to E. coli BL21 (DE3) and BL21-Codonplus (DE3). The preferred overexpression was achieved when utilizing the strain BL21 (DE3)/pET28b. Apart from this expression system, however, an overexpression was not observed. The bioconversion transforming E-pyridine-3-aldoxime into 3-cyanopyridine was dependent on the overexpression level of OxdYH3-3. The initial activity for 3 h of BL21 (DE3)/pET28b-OxdYH3-3 toward E-2-furfurylaldoxime (75%) was 13% lower compared to the initial activity toward E-pyridine-3-aldoxime (88%). Even though the initial conversion was lower, BL21 (DE3)/pET28b-OxdYH3-3 showed full conversion of E-2-furfurylaldoxime under formation of 2-furonitrile after 9 h of reaction time. The new recombinant enzyme OxdYH3-3 was successfully overexpressed and used for the biocatalytic synthesis of the pharmaceutical intermediate 2-furonitrile. The enzyme OxdYH3-3 showed a high catalytic activity for aromatic aldoximes, which enables a perspective for an efficient production of aromatic nitriles.
Acknowledgements
We gratefully acknowledge generous support from the German Academic Exchange Service (DAAD) and Japan Society for the Promotion of Science (JSPS) under the joint Japan-Germany Research Cooperative Programme [DAAD grant number: 57345566]. This work was supported in part by a grant-in-aid for Scientific Research (S) from the Japan Society for Promotion of Sciences [Grant No. 17H06169].
Disclosure statement
No potential conflict of interest was reported by the authors.