一株产低温纤维素酶放线菌的分离与产酶研究
Isolation,identification and characterization of a cold-adapted cellulase-producing psychrotrophic Streptomyces sp.
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摘要: 用羧甲基纤维素钠-刚果红培养基从内蒙大青沟采集的森林土壤中分离了一株产纤维素酶的耐低温菌,命名为ND2-1,其形态和16S r DNA序列分析结果表明ND2-1为链霉菌属(Streptomyces sp.)的放线菌。ND2-1能在1035℃范围内生长,最适生长温度为25℃,属耐低温菌。滤纸崩解实验表明,ND2-1能高效降解纤维素。ND2-1在25℃条件下,在含有2 g/L羧甲基纤维素钠(CMC-Na)的培养基中培养3 d后酶活性最高。对其酶学性质的初步研究结果表明:该菌株所产纤维素酶在p H3.09.0范围内稳定,且酶活性都较高,最适反应p H为7.0;最适反应温度为30℃,K+和Cu2+对酶活有抑制作用,Mn2+能提高相对酶活性至166.7%。Abstract: In this article,a cold-adapted cellulase-producing actinomycete,named ND2-1,was isolated form soil collected in Daqing Trench of Inner Mongolia. The morphological characteristics and 16 S r DNA sequence analysis showed that ND2-1 belongs to Streptomyces sp.. ND2-1 could grow at 10 ~35 ℃ and its optimum growth temperature was 25 ℃,indicating that it was a psychrotrophic bacterium. ND2-1 could disintegrate filter paper efficiently. The measured cellulase activity was the highest when 2 g/L of carboxymethylcellulose sodium(CMC-Na) was contained in the medium after cultivated at 25 ℃ for 3 days. The cellulase produced by ND2-1 was stable through p H3.0 ~9.0,the optimum reaction p H of the enzymewas 7.0,and the optimum reaction temperature was 30 ℃. K+and Cu2+could cause the inhibition of the enzyme activity. Mn2+improved the relative enzyme activity to 166.7%.