摘要
从我国寒冷地区筛选到一株能产低温降解酶的菌株.细菌学形态及16S rDNA鉴定表明,该菌株属希瓦氏菌属(Shewanella),最适生长温度为5～15℃,属耐冷菌,并暂命名为Shewanella sp.J5.菌株J5分泌的降解酶中蛋白酶和淀粉酶所表现的活力较高,在0℃下分别仍能保持20%和40%的酶活性,最适温度分别为40℃和30℃,最适pH分别为8.0和7.0～10.0,且对热敏感,属于碱性低温酶;金属离子中Mn2+、Fe2+对蛋白酶有明显的促进作用,而淀粉酶对金属依赖性较小;HPSEC结果表明,低温蛋白酶在水解酪蛋白过程中,对相对分子质量>10 000的大分子肽水解能力很强.脱氢酶酶活测定结果表明,低温下菌株活性显著高于常温活性污泥,5℃下,添加菌株J5到活性污泥中可使废水COD去除率提高33%.因此,该菌株在低温污水处理上具有一定的应用前景.
A strain producing cold-adapted degradation enzyme was isolated from cold northern China.The strain was identified as the genus Shewanella by the morphological identification and 16S rDNA sequence analysis,and named Shewanella sp.J5.The optimal growth temperature of strain J5 was 5～15 ℃,indicating that it was a psychrotrophic bacterium.The activities of protease and amylase were the strongest among those enzymes produced by strain J5,and sensitive to high temperature.Property test showed the protease had 20% residual activity at 0 ℃,and the optimal temperature and pH were 40 ℃ and 8.0,respectively,while the amylase could keep 40% residual activity at 0 ℃,and the optimal temperature and pH range were 30 ℃ and 7.0～10.0,respectively.The protease activity could be obviously stimulated by Mn2＋ and Fe2＋.HPSEC results showed that in the process of hydrolysis of casein protein the macromolecular peptides were easily degraded into small peptides by the protease.Compared with activated sludge,strain J5 possessed higher dehydrogenase activity at low temperatures.At 5 ℃,the removal rate of COD could increase by about 33% in activated sludge after adding this strain.It suggests that this strain may have broad application in cryogenic wastewater treatment.
出处
《应用与环境生物学报》
CAS
CSCD
北大核心
2010年第6期870-874,共5页
Chinese Journal of Applied and Environmental Biology
关键词
耐冷菌
SHEWANELLA
碱性低温酶
蛋白酶
淀粉酶
生物降解
污水处理
psychrotrophic bacterium
Shewanella
alkaline cold-adapted enzyme
protease
amylase
biodegradation
wastewater treatment
