胡晓娟, 文国樑, 徐煜, 苏浩昌, 徐武杰, 陈作志, 张殿昌, 王晶晶, 曹煜成. 南海岛礁鱼源产蛋白酶菌株热带芽孢杆菌BTZB2的特性研究[J]. 南方水产科学. DOI: 10.12131/20240075
引用本文: 胡晓娟, 文国樑, 徐煜, 苏浩昌, 徐武杰, 陈作志, 张殿昌, 王晶晶, 曹煜成. 南海岛礁鱼源产蛋白酶菌株热带芽孢杆菌BTZB2的特性研究[J]. 南方水产科学. DOI: 10.12131/20240075
HU Xiaojuan, WEN Guoliang, XU Yu, SU Haochang, XU Wujie, CHEN Zuozhi, ZHANG Dianchang, WANG Jingjing, CAO Yucheng. Characterization of proteinase-producing strain Bacillus tropicalis BTZB2 from source of fish in reef of South China Sea[J]. South China Fisheries Science. DOI: 10.12131/20240075
Citation: HU Xiaojuan, WEN Guoliang, XU Yu, SU Haochang, XU Wujie, CHEN Zuozhi, ZHANG Dianchang, WANG Jingjing, CAO Yucheng. Characterization of proteinase-producing strain Bacillus tropicalis BTZB2 from source of fish in reef of South China Sea[J]. South China Fisheries Science. DOI: 10.12131/20240075

南海岛礁鱼源产蛋白酶菌株热带芽孢杆菌BTZB2的特性研究

Characterization of proteinase-producing strain Bacillus tropicalis BTZB2 from source of fish in reef of South China Sea

  • 摘要: 深远海及南海岛礁海域较近海海域受人类活动的影响小,微生物资源丰富。金带齿颌鲷 (Gnathodentex aurolineatus) 是南海典型的珊瑚礁食肉鱼类之一,其肠道微生物群落具有较高的碳源代谢能力。为挖掘南海典型岛礁鱼类肠道微生物中可培养蛋白酶的菌株资源,从南海渚碧礁海域金带齿颌鲷肠道样品中富集筛选到产蛋白酶菌株BTZB2,其在酪蛋白平板上具有明显水解圈,水解圈直径与菌落直径的比值在第24小时达3.0。从分子水平结合细菌形态学特征及生理生化特性分析,确定该菌株为热带芽孢杆菌 (Bacillus tropicus)。该菌株最优产蛋白酶条件为:pH 8、盐度15‰、温度30 ℃、培养时间48 h、初始菌量105 CFU·mL−1。优化后该菌株发酵48 h后的蛋白酶活力可达319.48 U·mL−1,较筛选时菌株的酶活力 (124.55 U·mL−1) 提高了156.5%。在组合1 (pH 7、盐度22‰、温度30 ℃、初始接种量105 CFU·mL−1) 和组合2 (pH 8、盐度15‰、温度 30 ℃、初始接种量105 CFU·mL−1) 2种优化条件下,发酵第24小时粗酶液的比活力分别达 975.34和 889.97 U·mg−1,第48小时粗酶液的比活力分别达1 836.51和2 400.83 U·mg−1。结果表明,热带芽孢杆菌BTZB2具有良好的产蛋白酶能力,可作为南海鱼源功能微生物菌剂资源的备选菌株。

     

    Abstract: Deep sea and islands and reefs in the South China Sea with abundant microbial resources are less affected by human activities than the nearshore waters. As one of the typical coral reef carnivorous fish in the South China Sea, Gnathodentex aurolineatus' intestinal microbiota has a high ability to metabolize carbon sources. To explore cultivable proteinase-producing strains from the intestinal microbiota of typical reef fish in the South China Sea, we selected the proteinase-producing strains from the intestinal microbiota of G. aurolineatus in Zhubi Reef of the South China Sea, and isolated the strain BTZB2. It had a clear hydrolysis circle on the casein plate, and the ratio of hydrolysis circle diameter to colony diameter reached 3.0 at 24th hour. The strain was identified as Bacillus tropicus on molecular level, combining with morphological and physiological characteristics of bacteria. The optimal conditions for the protease production of this strain were pH of 8.0, salinity of 15‰, temperature of 30 ℃, cultivation time of 48 h and initial bacterial count of 105 CFU·mL−1. After fermentation for 48 h, the protease production activity of this strain reached 319.48 U·mL−1, 156.5% higher than that of the screened strain (124.55 U·mL−1). Under the two optimal conditions: Combination 1 (pH of 7, salinity of 22‰, temperature of 30 ℃, initial inoculation volume of 105 CFU·mL−1) and Combination 2 (pH of 8, salinity of 15‰, temperature of 30 ℃, initial inoculation volume of 105 CFU·mL−1), the specific activities of crude enzyme solution for 24 h were 975.34 and 889.97 U·mg−1, and those for 48 h were 1 836.51 and 2 400.83 U·mg−1, respectively. The results indicate that B. tropicus BTZB2 has a good proteinase production ability, and it can be used as a candidate strain of functional microbial resource from fish in the South China Sea.

     

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