A Polysaccharide-Degrading Marine Bacterium Flammeovirga sp.MY04 and Its Extracellular Agarase System  

作　　者：HAN Wenjun GU Jingyan YAN Qiujie LI Jungang WU Zhihong GU Qianqun LI Yuezhong 

机构地区：[1]Key Laboratory of Marine Drugs,Chinese Ministry of Education,School of Medicine and Pharmacy,Ocean University of China,Qingdao 266003,P.R.China [2]School of Life Science and Biotechnology,Mianyang Normal University,Mianyang 621000,P.R.China [3]State Key Laboratory of Microbial Technology,School of Life Science,Shandong University,Jinan 250100,P.R.China

出　　处：《Journal of Ocean University of China》2012年第3期375-382,共8页中国海洋大学学报（英文版）

基　　金：supported by the Scientific Research Fund of the Sichuan Provincial Education Department(09ZA181);by grants from the State Key Laboratory of Microbial Technology (M2010-12);the National Science Foundation of China (30870001)

摘　　要：Bacteria of the genus Flammeovirga can digest complex polysaccharides (CPs), but no details have been reported regarding the CP depolymerases of these bacteria. MY04, an agarolytic marine bacterium isolated from coastal sediments, has been identified as a new member of the genus Flammeovirga. The MY04 strain is able to utilize multiple CPs as a sole carbon source and grows well on agarose, mannan, or xylan. This strain produces high concentrations of extracellular proteins (490 mg L-1 ± 18.2 mg L-1 liquid culture) that exhibit efficient and extensive degradation activities on various polysaccharides, especially agarose. These proteins have an activity of 310 U mg-1 ± 9.6 U mg-1 proteins. The extracellular agarase system (EAS) in the crude extracellular enzymes contains at least four agarose depolymerases, which are with molecular masses of approximately 30-70 kDa. The EAS is stable at a wide range of pH values (6.0-11.0), temperatures (0-50℃), and sodium chloride (NaCl) concentrations (0- 0.9 mol L-1). Two major degradation products generated from agarose by the EAS are identified to be neoagarotetraose and neoagarohexaose, suggesting that β-agarases are the major constituents of the MY04 EAS. These results suggest that the Flammeovirga strain MY04 and its polysac-charide-degradation system hold great promise in industrial applications.Bacteria of the genus Flammeovirga can digest complex polysaccharides （CPs）, but no details have been reported regarding the CP depolymerases of these bacteria. MY04, an agarolytic marine bacterium isolated from coastal sediments, has been identified as a new member of the genus Flammeovirga. The MY04 strain is able to utilize multiple CPs as a sole carbon source and grows well on agarose, mannan, or xylan. This strain produces high concentrations of extracellular proteins （490 mg L-1 ± 18.2 mg L-1 liquid culture） that exhibit efficient and extensive degradation activities on various polysaccharides, especially agarose. These proteins have an activity of 310 U mg-1 ± 9.6 U mg-1 proteins. The extracellular agarase system （EAS） in the crude extracellular enzymes contains at least four agarose depolymerases, which are with molecular masses of approximately 30-70 kDa. The EAS is stable at a wide range of pH values （6.0-11.0）, temperatures （0-50℃）, and sodium chloride （NaCl） concentrations （0- 0.9 mol L-1）. Two major degradation products generated from agarose by the EAS are identified to be neoagarotetraose and neoagarohexaose, suggesting that β-agarases are the major constituents of the MY04 EAS. These results suggest that the Flammeovirga strain MY04 and its polysac-charide-degradation system hold great promise in industrial applications.

关 键 词：Flammeovirga polysaccharide degradation extracellular agarase system neoagaro-oligosaccharide 

分 类 号：TQ929[轻工技术与工程—发酵工程] Q938.8[生物学—微生物学]