生物絮团中异养亚硝化菌的分离鉴定及其特性

采用富集培养、分离纯化等微生物学手段,从对虾养殖池的生物絮团中筛选出两株对氨氮具有高转化率的菌株.16S rRNA测序及系统发育分析结果表明,两株菌均属于盐单胞菌属,菌株2011072708与食物盐单胞菌Halomonas alimentaria有99％的同源性,而菌株2011072709与胜利盐单胞菌H.shengliensis有100％的同源性.比较研究了两株菌在不同温度、盐度、pH、碳氮比条件下对氨氮的转化率,菌株2011072708在温度37℃、盐度30～40、pH 8、碳氮比28的条件下对氨氮的转化率最高;菌株2011072709在温度27～42℃、盐度40～50、pH 6、碳氮比21的条件下对氨氮的转化率最高.研究结果表明,胜利盐单胞菌（2011072709）对温度、盐度、pH、碳氮比等各方面的适应性优于食物盐单胞菌（2011072708）,更适合在生物絮团技术中得到应用.

Isolation and identification of heterotrophic nitrosobacteria from bio-flocs and analysis of their characteristics

Two strains of nitrosobacteria with high ammonia transformation rate were isolated by enrichment and selective culture from bio-flocs of shrimp culture ponds.Sequences of 16S rRNA indicated that both strains belonged to the genus Halomonas sp.,while strain 2011072708 was identified as H.alimentaria with 99% similarity,and strain 2011072709 as H.shengliensis with 100% similarity.Ammonia transformation rates of the two strains were compared under different temperatures,salinities,pH,and C/N ratios.The ammonia transformation rate of strain 2011072708 reached the highest level at 37 ℃,30～40,pH 8,and C/N ratio of 28,while that of strain 2011072709 reached the maximum at 27～42 ℃,40～50,pH 6,and C/N ratio of 21.The present study showed high ammonia transformation rates in both nitrosobacteria strains isolated from bio-flocs.Strain H.shenliensis （2011072709） had better adaptability to temperature,salinity,pH,and C/N ratio than H.alimentaria （2011072708）,and may be more suitable for application in bio-flocs technology.