大肠杆菌表达抗脂多糖因子的发酵条件优化

抗脂多糖因子(anti-lipopolysaccharide factor,ALF)作为一种重要的抗菌肽,具有抗菌性强,抗菌谱广的特点.将中华绒螯蟹(Eriocheir sinensis)抗脂多糖因子基因ALF克隆至pET32a载体获得原核表达载体.为了提高ALF融合蛋白在大肠杆菌中的可溶性表达量,保持抑菌活性,对已构...

Optimization of Fermentation Conditions for Production of Anti-lipopolysaccharide Factor in Escherichia coli

Anti-lipopolysaccharide factor (ALF), as an important antimicrobial peptide, has strong ability and wide spectrum of antimicrobial activity. An ALF gene isolated from Eriocheir sinensis was cloned in pET32a and transformed into Escherichia coli. In this study, in order to improve the soluble expression of Trx-ALF in Escherichia coli and keep its antimicrobial activity, several fermentation factors were evaluated with one-factor-at-a-time design. The highest level of ALF expression was obtained in the medium containing 2.5 g/L sucrose, 10 g/L yeast extract, 2.4 g/L (NH4)2SO4, 12.8 g/L Na2HPO4, 3 g/L KH2PO4, 10.5 g/L NaCl, 2 mmol/L MgSO4, 0.1 mmol/L CaCl2 with pH 6.5. The optimal culture conditions were as follows: a cell optical density of 0.8 at 600 nm before induction, an IPTG concentration of 0.5 mmol/L, a post-induction temperature of 33℃ and a post-induction time of 5 h. The recombinant fusion protein showed an antimicrobial activity against Micrococcus luteus.