具有多种胞外酶的对虾肠道黏附菌的分离和鉴定

用对虾饲料培养基从健康凡纳滨对虾肠道分离出500株黏附细菌,以产淀粉酶、脂肪酶和蛋白酶能力为指标,筛选出产该3种消化酶的细菌90株,占总菌株的18%.对其中生长较快的69株进行16S rDNA 基因测序,确定其分类地位.结果显示,69株菌分别属于不动杆菌属(Acinetobacter)、芽孢杆菌属(Bacillus)、葡萄球菌属(Staphylococcus)、假交替单胞菌属(Pseudoalteromonas)、气单胞菌属(Aeromonas)、嗜盐单胞菌属(Halomonas)、利斯顿氏菌属(Listonella)、莫拉氏菌属(Moraxella)等,其中数量最多是芽胞杆菌属,占鉴定细菌总数的53.62%,数量最少是气单胞菌属和嗜盐单胞菌属,均占鉴定细菌总数的2.90%.表明对虾肠道黏附菌群中具有较多能分泌多种消化酶的细菌,可进一步开发为促进对虾消化功能的益生菌

Isolation and Identification of Extracellular Enzyme-Producing Bacteria from the Intestinal Tract of Litopenaeus vannamei

500 strains adhesive bacteria were isolated from the intestinal tract of Litopenaeus vannamei by using shrimp-feed abstraction medium.All bacterial strains were screened for producing capability of protease,amylase and lipase.There were 90 strains that could produce three extracellular enzymes,18.0% of the total intestinal adhesive bacterial populations.69 strains with rapid growth were identified according to homology analysis of 16S rDNA sequences.They were grouped into eight genera as follows: Acinetobacter,Bacillus,Staphylococcus,Pseudoalteromonas,Aeromonas,Halomonas,Listonella,Moraxella,respectively.The dominant genus was Bacillus,which account for 53.62% of the total identified strains.There were least number strains belong to Aeromonas and Halomonas,which account for 2.90% of the total identified isolates,respectively.The results indicate that there are plentiful extracellular enzyme-producing bacterium adhered to intestine of shrimp with the potential to be promising probiotic of promoting digestion.