盐田藻垫细菌的分离及其胞外多糖的初步研究

Isolation of bacteria from saltern algal mats and the preliminary study on their exopolysaccharides

从连云港台南盐场采集藻垫,在去除底泥等杂物的藻类层中分离出5株不同的细菌(编号为A,B,C,D和E)。经VITEK-32鉴定,A和B可能是鲁氏不动杆菌(Acinetobacter lwoffii)或琼氏不动杆菌(Acinetobacter junii),C为溶血巴斯德菌(Pasteurella haemolytica),D为尿素放线杆菌(Actinobacillus ureae),E未鉴定出结果。在所试验的盐度范围内,细菌A、B和C的最适生长盐度都为25,细菌D的最适生长盐度为50～100,细菌E的最适生长盐度为25～50。细菌A,B,C,D和E细菌胞外多糖产率分别为0.628,0.362,0.177,0.269,0.719g/g细胞干质量。细菌A,B,C,D和E胞外多糖的糖醛酸质量分数分别为5.4%,9.9%,7.4%,9.8%和23.4%,均不含蛋白质,均无乳化、絮凝及凝胶活性。实验结果显示细菌胞外多糖是构成盐田藻垫胶质的重要组成部分,但从其物化性质看,细菌胞外多糖对藻垫的胶结和黏附性没有直接的影响。

Algal mats were collected from Tainan Saltworks of Lianyungang. Five kinds of bacteria （No. A, B, C, D and E） were isolated from the algal mats after mud and debris were removed from their surface. Bacteria were identified with the VITEK-32 automatic identification system. The results show that A and B may be Acinetobacter lwoffii or Acinetobacter junii, C was Pasteurella haemolytica, D was Actinobacillus ureae, and E couldn＇t be identified. In our tested range, the optimal salinities for the growths of A, B and C were 25, and for the growths of D and E, the optimal salinities were 50 -100 and 25 -50, respectively. The exopolysaccharide productivities of bacteria A, B, C, D and E were 0.628, 0.362, 0.177, 0.269 and 0.719 gram per gram cell dry weight, respectively. The uronic acid contents of bacteria A, B, C, D and E were 5.4%, 9.9%, 7.4%, 9.8% and 23.4%, respectively. All these exopolysaccharides did not contain protein, and they had no emulsion, flocculation or gel activities. The experimental results show that bacterial exopolysaccharide could be an important component of the colloid of saltern algal mats. However, on the point of physico-chemical properties, these exopolysaccharides had no direct influence on the gelling and adhesive properties of algal mats.