A total of 92 marine bacteria belonging to Pseudomonas, Pseudoalteromonas, Psychrobacter, and Shewanella were first screened for their proteolytic activity. In total, four Pseudomonas strains belonging to Ps. fluorescens, Ps. fragi, Ps. gessardii, and Ps. marginalis; 14 Pseudoalteromonas strains belonging to Psa. arctica, Psa. carrageenovora, Psa. elyakovii, Psa. issachenkonii, Psa. rubra, Psa. translucida, and Psa. tunicata; and two Shewanella strains belonging to S. baltica and S. putrefaciens were identified to have a weak to high proteolytic activity (from 478 to 4445 mU/mg trypsin equivalent) against skim milk casein as protein source. Further chitinolytic activity screening based on these 20 proteolytic strains using colloidal chitin yielded five positive strains which were tested against three different chitin substrates in order to determine the various types of chitinases. Among the strains that can produce both proteases and chitinases, Psa. rubra DSM 6842T expressed not only the highest proteolytic activity (2558 mU/mg trypsin equivalent) but also the highest activity of exochitinases, specifically, β-N-acetylglucosaminidase (6.33 mU/107 cfu) as well. We anticipate that this strain can be innovatively applied to the valorization of marine crustaceans side streams.

中文翻译：

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海洋细菌胞外蛋白酶和几丁质酶的定量

首先筛选了属于假单胞菌属、假交替单胞菌属、假杆菌属和希瓦氏菌属的 92 种海洋细菌的蛋白水解活性。总共有四个假单胞菌菌株属于 Ps。荧光剂，Ps。弗拉吉，PS。gessardii 和 Ps。边缘；属于 Psa 的 14 种假交替单胞菌菌株。北极，诗篇。卡拉胶，诗篇。埃利亚科维，诗篇。伊萨琴科尼，诗篇。鲁布拉，诗篇。translucida 和 Psa。突尼斯；和属于 S. baltica 和 S. putrefaciens 的两种 Shewanella 菌株被鉴定为对作为蛋白质来源的脱脂牛奶酪蛋白具有弱到高的蛋白水解活性（从 478 到 4445 mU/mg 胰蛋白酶当量）。使用胶体几丁质基于这 20 种蛋白水解菌株的进一步几丁质水解活性筛选产生了五个阳性菌株，它们针对三种不同的几丁质底物进行了测试，以确定各种类型的几丁质酶。在可以产生蛋白酶和几丁质酶的菌株中，Psa。rubra DSM 6842T 不仅表达最高的蛋白水解活性（2558 mU/mg 胰蛋白酶当量），而且外切多糖酶的活性也最高，特别是 β-N-乙酰氨基葡萄糖苷酶（6.33 mU/107 cfu）。我们预计这种菌株可以创新地应用于海洋甲壳类侧流的增值。rubra DSM 6842T 不仅表达最高的蛋白水解活性（2558 mU/mg 胰蛋白酶当量），而且外切多糖酶的活性也最高，特别是 β-N-乙酰氨基葡萄糖苷酶（6.33 mU/107 cfu）。我们预计这种菌株可以创新地应用于海洋甲壳类侧流的增值。rubra DSM 6842T 不仅表达最高的蛋白水解活性（2558 mU/mg 胰蛋白酶当量），而且外切多糖酶的活性也最高，特别是 β-N-乙酰氨基葡萄糖苷酶（6.33 mU/107 cfu）。我们预计这种菌株可以创新地应用于海洋甲壳类侧流的增值。