Effects of Signal Peptides on Extracellular Expression of Cyclodextrin Glycosyltransferase in Bacillus subtilis

Abstract:

CGT⊿ECBMAmy gene from E. coli pET-20b（+）/CGT?驻E-CBMAmy was cloned and inserted into the expression plasmid pMA0911-SPs containing six different signal peptides（estA，bpr，vpr，yncM，yvgO and ywbN ），which were further transformed into B. subtilis WB600 for overexpression to obtain six recombinant strains. The results showed that estA was the optimal signal peptide among all the signal peptides under the same culture conditions，the yields of AA-2G was up to 0.81 g/L，obvious higher than that of the other five strains. Therefore，WBpMB/CGT?驻E-CBMAmy was chosen as the starting strain and the optimum conditions for extracellular expression of CGT?驻E-CBMAmy were investigated in shaking flask. Finally，the high expression of CGT?驻E-CBMAmy enzyme was achieved，and the yields of AA-2G was about 2.16 times higher than that before optimization and the conversion rate of VC reached 21.9%.