日本三宅岛火山土壤中硫代硫酸盐氧化菌的分离、生物学特性及鉴定

摘要

[目的]利用培养法从日本三宅岛火山土壤(堆积年限131年)中分离到一株能氧化分解硫代硫酸盐的细菌MU2A-22T.[方法]用培养法对该菌株MU2A-22T进行了生理生化性质以及分类学位置上的确定.[结果]菌株MU2A-22T为革兰氏阴性,短杆状或球状.理化性质表明该菌株能利用葡萄糖、L-阿拉伯糖、葡萄糖酸盐、己二酸酯、dL-苹果酸钠、硫代硫酸钠(最适浓度为2.5 mmol/L)为唯一碳源进行自养生长.最适生长温度为25℃-30℃,最适pH为6.0-8.0.菌株MU2A-22T的16S rRNA序列与菌株Paracoccus solventivorans 6637T亲缘关系最近,序列相似性为97％,编码核酮糖-1,5-二磷酸羧化酶/加氧酶(Rubisco)的基因也被确定.对Paracoccus属内几种近缘菌的脂肪酸分析,证明菌株MU2A-22T中含有Paracoccus 属的特征氨基酸,其中含量大于10％的分别为C18∶1(74.7％)和C18∶0(12.1％). DNA-DNA杂交实验表明,菌株MU2A-22T与Paracoccus solventivorans 6637TDNA的相似度为49.3％.MU2A-22T菌株G+C含量为66.5％-66.7％.[结论]菌株MU2A-22T为Paracoccus属内的一新种菌(登录号GQ452286),命名为Paracoccus scorialis sp.nov..%[Objective]A bacterium MU2A-22T,which was isolated from 131-year-old volcanic deposits of Miyake-jima island (Japan),has been characterized for its capability of thiosulfate oxidizing.[Methods]The culture-based method was used to isolate and identify strain MU2A-22r for its phenotypic characteristics and taxonomic position.[Results]The strain MU2A-22T was Gram-negative,short rod- to coccus-shaped.This bacterium could utilize D-glucose,L-arabinose,gluconate,adipate and dL-malate as sole carbon source.Strain MU2A-22T was able to use thiosulfate as an energy source with the optimum concentration of 2.5 mmol/L.The optimum growth condition was 25 ℃-30 ℃ and pH was 6.0-8.0 respectively.16S rRNA gene sequence analysis indicated that this strain was closely related to Paracoccus solventivorans 6637T within Alphaprotebacteria (97％ 16S rRNA gene sequence similarity).Its possess of the large-subunit gene of ribulose 1,5-bisphosphate carboxylase/oxygenase (rbcL) has also been identified.The cellular fatty acid profiles was characterized of the genus Paracoccus.The major fatty acids (＞10％) were C18∶1(74.7％) and C18∶0(12.1％).DNA-DNA relatedness between strain MU2A-22T and P.solventivorans 6637T was 49.3％.G+C contents was 66.5％-66.7％.[Conclusion]As for the above results,strain MU2A-22T seemed to be a novel species in the genus Paracoccus with its accession number of GQ452286 and the name of Paracoccus scorialis sp.nov.was proposed.