产乙醇基因工程集胞藻的盐胁迫响应

Response of Genetically Engineered Synechocystis sp.to Salt Concentration for Production of Ethanol

采用含不同浓度NaCl的培养基培养产乙醇基因工程集胞藻,研究盐胁迫对其细胞生长和乙醇产量的影响,并探讨其响应机制.结果表明,随培养液中NaCl浓度提高,藻生长速率降低;盐胁迫损伤细胞光反应中心II的活性,抑制细胞的光合作用;盐浓度大于10g/L时,呼吸作用略有提高.随盐浓度提高,集胞藻的内源性代谢产物乙醇产量显著提高,在20g/L NaCl中培养,乙醇产量较对照提高91.8%.在盐胁迫条件下,基因工程集胞藻通过调节光合作用和呼吸作用效率、提高乙醇脱氢酶的活性而提高内源性的代谢以应对胁迫,同时提高乙醇产量.

The effects of NaCI concentration on ethanol production and biological response in genetically engineered cyanobacteria Synechocystis sp. PCC 6803 Syn-ZG25 were studied. The Syn-ZG25 grew in BG11 medium containing various NaC1 concentrations, resulting in decreased growth rate, photosystem II activity and photosynthesis rate with increasing of salt concentration. For Syn-ZG25 growing in more than 10 g/L NaC1, dark respiration rate increased. With increasing of salt concentration, catabolism of endogenous carbohydrate increased, and ethanol excretion rate increased accordingly. The ethanol yield of Syn-ZG25 growing in 20 g/L NaC1 was increased substantially by 91.8% to that in the control medium without NaC1. These results indicated that the Synechocystis sp. PCC 6803 Syn-ZG25 could regulate photosynthesis and respiration rates, presumably enhance catabolism of endogenous carbohydrate by enhancing activity of alcohol dehydrogenase, as the response to salt stress, and then resulting in the increase of ethanol yield.