中文摘要：

为筛选抗水产弧菌的益生菌株,自西沙海域采集的珊瑚和海水样品共分离到125株细菌,从中筛选出1株无溶血性且对多株病原菌具有拮抗作用的海洋细菌B1。基于生理生化及16SrDNA序列鉴定海洋细菌B1为短小芽孢杆菌。以副溶血弧菌13150为病原指示菌,用琼脂扩散法测定发酵液抑菌活性,并通过卤虫浸泡方式和药敏试验方法检测短小芽孢杆菌B1的安全性,同时进行温度、酸碱度、盐度的发酵条件优化研究。试验结果显示,短小芽孢杆菌B1对副溶血弧菌、溶藻弧菌、哈氏弧菌等有显著的拮抗作用;共培养试验显示,加入等量短小芽孢杆菌B1无菌上清液可显著抑制副溶血弧菌的生长;安全性试验发现,短小芽孢杆菌B1对卤虫的72h半致死密度为108cfu/mL,副溶血弧菌13150的72h半致死密度为105cfu/mL。此外,药敏试验表明,短小芽孢杆菌B1只对20种常规抗生素中的5种产生抗性;优化后的短小芽孢杆菌B1发酵条件为：温度30℃,pH 7.0,NaCl质量分数为2%。研究表明,短小芽孢杆菌B1具有防治水产养殖病原弧菌的应用潜力。

英文摘要：

In the present study,a marine bacterial strain Bacillus pumilus B1 without hemolysis was isolated from 125 strains collected in seawater and coral in Xisha,China,and identified by biochemical analysis and 16 SrRNA sequence methods.An agar antagonism assay revealed that the cell-free extracts of B1 showed greater inhibitory effects against the indicator pathogen Vibrio parahaemolyticus13150.The strain B1 was found to produce a wide zone of inhibition against several Vibrio sp.including V.alginolyticus,V.harveyi,and V.cholerae.The LC50 of Bacillus B1 was found to be 108 cfu/mL,and the LC50 of V.parahaemolyticus was 105 cfu/mL 72 hafter treatment in Artemia nauplii.Moreover,drug sensitivity tests showed that strain B1 was resistant to five antibiotics in 20 conventional antibiotics.The optimized fermentation of strain B1 was observed under conditions of 30 ℃,pH 7.0and a salinity of 2%.