一株溶藻细菌的分离鉴定及其溶藻特性

从对藻类及藻毒素有良好去除作用的海绵固定化微生物系统中分离到一株溶藻细菌P0 7,对该菌溶解铜绿微囊藻(Microcystisaeruginosa)、栅藻(Scenedesmus)及小球藻(Chlorella)的效果、溶藻方式进行了研究,利用16SrDNA序列分析对其进行了鉴定.结果表明,该菌株不但对铜绿微囊藻具有良好的溶解效果,而且对淡水中常见的栅藻及小球藻也具有良好的去除作用.初始菌浓度越大,溶藻效果越明显,达到最佳溶藻效果的时间越短.当菌浓度为2 . 4×10 7个·mL- 1 时,3d后铜绿微囊藻的去除率可达到81 .67% .该菌溶藻无需菌体与藻细胞直接接触,是通过分泌某种非蛋白质类物质溶藻.该菌革兰氏染色呈阳性,可运动;不能利用大多数常见碳源.16SrDNA序列分析表明,P0 7菌株与多株芽孢杆菌的16SrDNA核苷酸序列的同源性均在99. 7%以上,归属于芽孢杆菌属.

Isolation and identification of one algae-lysing Bacteria and its lytic character

An algae-lysing bacterium strain P07 was isolated from a biosystem immobilized on a sponge whose removal rates of algae and microcystin were high. Its lytic mode and effects on Microcystis aeruginosa, Scenedesmus and Chlorella were studied. The results showed that the strain P07 had excellent lytic effects not only on Microcystis aeruginosa, but also on Scenedesmus and Chlorella. The higher the start bacterium concentration was, the more obvious the lytic effect was, and the shorter the time reaching to attain the maximum rate of lytic effect was. At a concentration of 2.4×10⁷cells·mL^-1, the removal of Microcystis aeruginosa was 81.67% after 72 hours. The lytic effect on the Microcystis aeruginosa of bacterium P07 did not require physical contact between cells, but depended on the production of extracellular chemicals which are not proteins. The strain P07 was gram-positive and did not utilize the most of normal sources of carbon. The strain was identified by the sequence analysis of 16SrDNA. The sequence analysis of a 1 500 bp 16SrDNA fragment amplified from total DNA of strain P07 by PCR showed that it shares 99.7% sequence homology with some strain of Bacillus. According that, P07 belongs to phylogenetic bacteria of Bacillus classification.