累积番茄红素的大肠杆菌工程菌及其培养条件的研究

噬夏孢欧文氏菌番茄红素合成相关基因crtE, crtB, crtI同时克隆进表达载体pET-15b构建pET-15bcrtIEB，将该重组质粒转化E.coliBL21(DE3)构建工程菌,IPTG诱导工程菌累积红色色素，经HPLC和吸收光谱分析，工程菌中合成的色素为番茄红素。研究了碳源、金属离子、培养温度、诱导剂浓度、诱导时间等参数对工程菌生长及色素累积的影响，确定了合适的培养条件：培养基为改良LB培养基（蛋白胨10g/L、酵母提取物5g/L、麦芽糖5g/L、MgCl2 0.1g/L，NaCl 10g/L）；起始培养温度为37℃；培养至OD600为0.6左右时加入IPTG，终浓度为0.5mmol/L，诱导温度降至30℃；诱导时间为14h。发酵完成后工程菌的生物量（干重）为3.45g/L，番茄红素的最高含量可达5.8mg/gDW。

Studies of Escherichia coli accumulating lycopene and its culturing conditions

Three genes crtE, crtB, crtI related to lycopene synthesis in Erwinia uredovora were cloned into pET-15b to construct expressing vector pET-15bEIB. The expressing vector was introduced into E.coli BL21(DE3) to construct engineering bacteria. The engineering bacteria could accumulate a red pigment when induced by IPTG. The red pigment was lycopene as judged by absorbance spectra analysis and HPLC analysis. The engineering bacteria could grow to 3.45gDW/L and accumulate lycopene to 5.8mg/gDW under culturing conditions. The culturing conditions used were as follows: the medium was modified LB broth（Trypton 10g/L,Yeast Extract 5g/L,Maltose 5g/L,MgSO4 0.1g/L，NaCl 10g/L）, the engineering bacteia were first shake-cultured at 37℃ to OD600 of 0.6, and then IPTG was added to a final concentration of 0.5mmol/L, the engineering bacteria was further cultured for 14h at 30℃.