The Antarctic region is known for its ecological conditions and the presence of some of the rarest microorganisms on earth. Antarctic krill rapidly degrades while at rest or during transport due to high-activity enzymes in its flesh or from microbes. In this study, we analyzed the microbial diversity of the Antarctic krill, Euphausia superba , and identified the dominant bacteria that cause spoilage during storage and transport using culture-independent high-throughput sequencing and microbial pure culture methods. Antarctic krill samples were incubated at temperatures of 0 °C, 4 °C, 16 °C, and 25 °C to determine the microbial diversity and abundance in decaying marine krill samples. Metagenome high-throughput sequencing indicated that, under incubation at 4 °C and 0 °C for 24 h, the microbial diversity of the Antarctic krill samples was high, with high species richness of microbes adapted to the low-temperature environment, as indicated by the overwhelming dominance of Enterococcus and Bacillus . On the other hand, Psychrobacter became the dominant bacteria at storage temperatures of 16 °C and 25 °C. Quantitative PCR results demonstrated that the microbial copy number increased as the temperature increased from 0 to 25 °C, and the quantity of bacteria was much greater than that of fungi under the same storage conditions. Microbial pure culture methods demonstrated that Psychrobacter was the dominant genus at each incubation temperature after 24 h of storage. Psychrobacter sp. and Psychrobacter -like strains isolated from the Antarctic krill samples exhibited protease activity. Our laboratory results indicated that Psychrobacter was the primary cause of spoilage of the Antarctic krill, E. superba . The results from ITS rDNA fungal sequencing showed that unclassified Saccharomycetes were the predominant microbes in all the Antarctic krill samples.

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南极磷虾贮藏和加工过程中引起腐败的微生物多样性和优势细菌

南极地区以其生态条件和地球上一些最稀有微生物的存在而闻名。南极磷虾在休息或运输过程中会由于其肉中或微生物中的高活性酶而迅速降解。在本研究中，我们分析了南极磷虾的微生物多样性，并使用独立于培养的高通量测序和微生物纯培养方法确定了在储存和运输过程中导致腐败的优势细菌。南极磷虾样品在 0°C、4°C、16°C 和 25°C 的温度下孵育，以确定腐烂的海洋磷虾样品中的微生物多样性和丰度。宏基因组高通量测序表明，在4°C和0°C孵育24 h下，南极磷虾样品的微生物多样性较高，具有适应低温环境的微生物物种丰富度高，肠球菌和芽孢杆菌的压倒性优势表明。另一方面，在 16 °C 和 25 °C 的储存温度下，Psychrobacter 成为优势细菌。定量PCR结果表明，随着温度从0℃升高到25℃，微生物拷贝数增加，在相同储存条件下，细菌数量远大于真菌数量。微生物纯培养方法表明，在储存 24 小时后，在每个孵育温度下，Psychrobacter 是优势属。精神杆菌属 从南极磷虾样品中分离出的 Psychrobacter 和 Psychrobacter 样菌株表现出蛋白酶活性。我们的实验室结果表明，精神杆菌是南极磷虾腐败的主要原因，E. superba 。ITS rDNA 真菌测序结果表明，未分类的酵母菌是所有南极磷虾样本中的主要微生物。