Fig. 1
The effects of different single factors on the production of recombinant γ-CGTase from E. coli BL21 (DE3). a Soluble γ-CGTase expression in E. coli BL21 (DE3) cultured by different carbon sources. Lane M, protein ladder; lane 1, control (glycerol); lane 2, soluble starch; lane 3, sucrose; lane 4, maltose; lane 5, lactose; lane 6, glucose; lane 7, galactose; lane 8, arabinose; and lane 9, non-induced strain. b γ-CGTase activity in lytic supernatant and OD600 in shake-flask culture with different carbon sources. c Soluble γ-CGTase expression in E. coli BL21 (DE3) cultured by different nitrogen sources. Lane M, protein ladder; lane 1, non-induced strain; lane 2, (NH4)2SO4; lane 3, diammonium citrate; lane 4, NH4Cl; lane 5, tryptone; lane 6, yeast extract; lane 7, tryptone: yeast extract = 1:1; and lane 8, control (tryptone, yeast extract = 1:2). d γ-CGTase activity and OD600 in shake-flask cultures with different nitrogen sources. e Soluble γ-CGTase expression in E. coli BL21 (DE3) cultured by phosphate and different metal ions. lane M1, protein ladder; lane 1, non-induced strain; lane 2, K+; lane 3, Zn2+; lane 4, Fe3+; lane 5, Cu2+; lane 6, Fe2+; lane 7, Ca2+; lane M2, protein ladder; lane 8, Mn2+; lane 9, Mg2+; lane 10, Ni2+; lane 11, PO43−; and lane 12, control (no metal ions or PO43− added). f γ-CGTase activity and OD600 in shake-flask cultures with PO43− and different metal ions. The data were presented from three independent experiments