Enhanced a novel β-agarase production in recombinant Escherichia coli BL21(DE3) through induction mode optimization and glycerol feeding strategy  

作　　者：CHAN Zhuhua CHEN Xinglin HOU Yanping GAO Boliang ZHAO Chungui YANG Suping ZENG Runying 

机构地区：[1]Department of Bioengineering and Biotechnology, Huaqiao University [2]State Key Laboratory Breeding Base of Marine Genetic Resource, Third Institute of Oceanography State Oceanic Administration [3]School of Life Sciences, Xiamen University

出　　处：《Acta Oceanologica Sinica》2018年第2期110-118,共9页海洋学报（英文版）

基　　金：The Public Science and Technology Research Funds Projects of Ocean under contract No.201505026;the Fujian Province Natural Science Foundation under contract Nos 2016J01160 and 2017N0015;the Scientific Research Foundation of Third Institute of Oceanography,SOA under contract No.2016038

摘　　要：Agarases are hydrolytic enzymes that act on the hydrolysis of agar and have a broad range of applications in food,cosmetics and pharmaceutical industries. In this study, a glycerol feeding strategy based on induction mode optimization for high cell density and β-agarase production was established, which could effectively control acetate yield. First, exponential feeding strategy of glycerol with different overall specific growth rates（μ） was applied in the pre-induction phase. The results showed that the low μ（μ=0.2） was suggested to be the optimal for cell growth and β-agarase production. Second, the effects of induction temperature and the inducer concentration on cell growth and β-agarase production were investigated in the post-induction phase. When induced by isopropyl-β-d-thiogalactoside（IPTG）, the strategy of 0.8 mmol/L IPTG induction at 20℃ was found to be optimal for β-agarase production. When cultivation was induced by continuous lactose feeding strategy of 1.0 g/（L·h）, the β-agarase activity reached 112.5 U/mL, which represented the highest β-agarase production to date.Furthermore, the β-agarase was capable of degrading G. lemaneiformis powder directly to produce neoagarooligosaccharide, and the hydrolysates were neoagarotetraose（NA4） and neoagarohexaose（NA6）. The overall research may be useful for the industrial production and application of β-agarase.Agarases are hydrolytic enzymes that act on the hydrolysis of agar and have a broad range of applications in food,cosmetics and pharmaceutical industries. In this study, a glycerol feeding strategy based on induction mode optimization for high cell density and β-agarase production was established, which could effectively control acetate yield. First, exponential feeding strategy of glycerol with different overall specific growth rates（μ） was applied in the pre-induction phase. The results showed that the low μ（μ=0.2） was suggested to be the optimal for cell growth and β-agarase production. Second, the effects of induction temperature and the inducer concentration on cell growth and β-agarase production were investigated in the post-induction phase. When induced by isopropyl-β-d-thiogalactoside（IPTG）, the strategy of 0.8 mmol/L IPTG induction at 20℃ was found to be optimal for β-agarase production. When cultivation was induced by continuous lactose feeding strategy of 1.0 g/（L·h）, the β-agarase activity reached 112.5 U/mL, which represented the highest β-agarase production to date.Furthermore, the β-agarase was capable of degrading G. lemaneiformis powder directly to produce neoagarooligosaccharide, and the hydrolysates were neoagarotetraose（NA4） and neoagarohexaose（NA6）. The overall research may be useful for the industrial production and application of β-agarase.

关 键 词：β-agarase Escherichia coli process optimization glycerol feeding strategy neoagarooligosaccharide 

分 类 号：Q936[生物学—微生物学]