启动子PpetE与Pcpc560对集胞藻PCC 6803生物合成乙醇的影响

Effects on the Biosynthesis of Ethanol by Promoters PpetE and Pcpc560 in Synechocystis sp.PCC 6803

为了增加工程集胞藻PCC 6803的乙醇合成产量,通过选用强启动子Pcpc560 驱动并提高外源乙醇合成基因(pdc,yqhD)的表达,从而促进乙醇的生产。具体方法利用同源双交换引入来源于运动型发酵单胞菌的丙酮酸脱羧酶基因(pdc)与来源于大肠杆菌的NADPH依赖型醛还原酶基因(yqhD)并选用不同的启动子来驱动其表达。通过逆转录定量PCR分析,比较在不同启动子驱动的情况下,外源乙醇合成基因(pdc,yqhD)的表达情况并检测相应突变株的乙醇产量。结果显示相较于中等启动子,铜离子诱导启动子PpetE,来源于集胞藻PCC 6803的光强启动子Pcpc560显著促进了外源乙醇合成基因(pdc,yqhD)的表达,并增加了工程菌株乙醇合成的产量。超强启动子Pcpc560搭配pdc,yqhD的组合表达,显著提高了工程菌株的乙醇合成产量。

To increase the synthesized ethanol yield of engineered Synechocystis sp.PCC 6803,the strong promoter Pcpc560 was selected to drive and enhance the expression of exogenous ethanol-producing genes(pdc,and yqhD),thus ethanol yield was enhanced.The specific methods were that by homologous double exchange,the pyruvate decarboxylase gene(pdc)derived from Zymomonas mobilis and NADPH-dependent aldehyde reductase(yqhD)derived from Escherichia coli were introduced and driven by different promoters.By reverse transcription quantitative PCR analysis,the expressions of exogenous ethanol-producing genes(pdc and yqhD)and the ethanol yields of corresponding engineered strains under the driven of different promoters were detected and compared.The results showed that the light intensity promoter,Pcpc560 derived from the Synechocystis sp.PCC 6803 significantly enhanced the expressions of the exogenous ethanol-producing genes(pdc and yqhD)and increased synthesized ethanol output compared with the medium copper ion-induced promoter PpetE.The combined expression of super-strong promoter Pcpc560 with pdc and yqhD has significantly improved the ethanol production of the engineered strain.