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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. 18.104.22.168) 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.