Published: CABEQ 19 (4) (2005) 367–372
Paper type: Original Scientific Paper

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A Novel Three-stage Process for Continuous Production of Penicillin G Acylase by a Temperature-sensitive Expression System of Bacillus subtilis Phage phi105

X. Chen and P. Cen

This study is pertaining to the production of penicillin G acylase (PGA) by Bacillus subtilis ϕ105MU331 in which PGA gene, under the control of thermal-induced promoter, was integrated. The key process parameters including induced-temperature, induced- time, and culture temperature were optimized in flask culture. A three-stage cultivation process was developed for PGA production with the expression system of B. subtilis ϕ105MU331. Furthermore, a bioreactor with a thermal-induced apparatus was designed for continuous production of PGA, where cell growth, induction, and PGA expression could be conducted separately. At a dilution rate of 0.20 h–1, PGA production was taken under continuous cultivation in three-stage process. After continuous feeding, the cell density, pH, and residual glucose in the first- and third-reactor were maintained steady for up to 40 h. These results suggested that the new three-stage process might be feasible and very efficient for production of heterologous proteins.

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penicillin G acylase, Bacillus subtilis, prophage, three-stage cultivation process