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Acetaldehyde Detoxification Using Resting Cells of Recombinant Escherichia coli Overexpressing Acetaldehyde Dehydrogenase

Yao, Zhengying, Zhang, Chong, Zhao, Junfeng, Lu, Fengxia, Bie, Xiaomei, Lu, Zhaoxin
Applied biochemistry and biotechnology 2014 v.172 no.4 pp. 2030-2040
Escherichia coli, acetaldehyde, acetaldehyde dehydrogenase, biodegradation, catalytic activity, inoculum, pH, response surface methodology, temperature
Acetaldehyde dehydrogenase (E.C. plays a key role in the acetaldehyde detoxification. The recombinant Escherichia coli cells producing acetaldehyde dehydrogenase (ist-ALDH) were applied as whole-cell biocatalysts for biodegradation of acetaldehyde. Response surface methodology (RSM) was employed to enhance the production of recombinant ist-ALDH. Under the optimum culture conditions containing 20.68 h post-induction time, 126.75 mL medium volume and 3 % (v/v) inoculum level, the maximum ist-ALDH activity reached 496.65 ± 0.81 U/mL, resulting in 12.5-fold increment after optimization. Furthermore, the optimum temperature and pH for the catalytic activity of wet cells were 40 °C and pH 9.5, respectively. The biocatalytic activity was improved 80 % by permeabilizing the recombinant cells with 0.075 % (v/v) Triton X-100. When using 2 mmol/L NAD⁺as coenzyme, the permeabilized cells could catalyze 98 % of acetaldehyde within 15 min. The results indicated that the recombinant E. coli with high productivity of ist-ALDH might be highly efficient and easy-to-make biocatalysts for acetaldehyde detoxification.