Abstract: A metagenomic library recombinant clone CAPL3, an Escherichia coli strain generated by transformed with metagenomic library from deep-sea sediments, can efficiently produce cold active lipase. The effects of both temperature and dissolved oxygen (DO) on cold active lipase production by batch culture of metagenomic library recombinant clone (CAPL3) from deep-sea sediment were investigated. First, a two-stage temperature control strategy was developed, in which the temperature was kept at 34℃ for the first 15 h, and then switched to 30℃. The cold active lipase activity and productivity reached 315.2 U·ml^-1 and 8.08 U·ml^-1·h^-1, respectively, increased by both 14.5% compared to the results obtained with temperature controlled at 30℃. In addition, different DO control modes were conducted, based on the data obtained from the different DO control strategies and analysis of kinetics parameters at different DO levels. A step-wise temperature and DO control strategy were developed to improve lipase production, i.e., temperature and DO level were controlled at 34℃, 30% during 0-15 h; 30℃, 30% during 15-18 h, and 30℃, 20% during 18-39 h. With this strategy, the maximum lipase activity reached 354.6 U·ml^-1 at 39 h, which was 28.8% higher than that achieved without temperature and DO control (275.3 U·ml^-1).

Key words: Deep-sea sediments, Metagenomic library, Cold active lipase, Step-wise temperature and DO control strategy

摘要： A metagenomic library recombinant clone CAPL3, an Escherichia coli strain generated by transformed with metagenomic library from deep-sea sediments, can efficiently produce cold active lipase. The effects of both temperature and dissolved oxygen (DO) on cold active lipase production by batch culture of metagenomic library recombinant clone (CAPL3) from deep-sea sediment were investigated. First, a two-stage temperature control strategy was developed, in which the temperature was kept at 34℃ for the first 15 h, and then switched to 30℃. The cold active lipase activity and productivity reached 315.2 U·ml^-1 and 8.08 U·ml^-1·h^-1, respectively, increased by both 14.5% compared to the results obtained with temperature controlled at 30℃. In addition, different DO control modes were conducted, based on the data obtained from the different DO control strategies and analysis of kinetics parameters at different DO levels. A step-wise temperature and DO control strategy were developed to improve lipase production, i.e., temperature and DO level were controlled at 34℃, 30% during 0-15 h; 30℃, 30% during 15-18 h, and 30℃, 20% during 18-39 h. With this strategy, the maximum lipase activity reached 354.6 U·ml^-1 at 39 h, which was 28.8% higher than that achieved without temperature and DO control (275.3 U·ml^-1).

关键词: Deep-sea sediments, Metagenomic library, Cold active lipase, Step-wise temperature and DO control strategy