Bioresource Technology, Vol.102, No.22, 10671-10678, 2011
Overproduction of alkaline polygalacturonate lyase in recombinant Escherichia coli by a two-stage glycerol feeding approach
This work aims to achieve the overproduction of alkaline polygalacturonate lyase (PGL) with recombinant Escherichia coli by a two-stage glycerol feeding approach. First, the PGL coding gene from Bacillus subtilis WSHB04-02 was expressed in E. coli BL21 (DE3) under the strong inducible T7 promoter of the pET20b (+) vector. And then the influence of media composition, induction temperature, and inducer isopropyl beta-D-1-thiogalactopyranoside (IPTG) concentration on cell growth and PGL production was investigated. Finally, a two-stage glycerol feeding strategy was proposed and applied in a 3-L fermenter, where cultivation was conducted at a controlled specific growth rate (mu(set) = 0.2) during pre-induction phase, followed by a constant glycerol feeding rate of 12 ml h(-1) at post-induction phase. The total PGL yield reached 371.86 U mL(-1), which is the highest PGL production by recombinant E. coil expression system. (C) 2011 Elsevier Ltd. All rights reserved.
Keywords:Escherichia coli;Bacillus subtilis;Alkaline polygalacturonate lyase;Extracellular expression