一株抗锰土壤芽胞杆菌的分离鉴定与生物学活性分析

Identification and Characterization of a Manganese-resistant Bacilli Isolate from Soil

摘要:

从山东崅屿采集的黄棕壤中分离得到一株具有抗Mn (II)和Mn (II)氧化双重活性的芽胞杆菌, 其最高Mn (II)耐受浓度达到130 mmol/L, 对Mn (II)的氧化活性为3.3 μmol/(L·d)。通过个体形态与培养特征观测、生理生化反应、G + C mol% 测定和16S rDNA序列比对分析等鉴定, 确定该菌株为巨大芽胞杆菌(Bacillus megaterium), 命名为MB283。该菌株在添加Mn (II) (10 mmol/L)条件下比不添加Mn (II)表现出相对较快的生长速率。采用高温培养并结合0.01% SDS处理, 从MB283菌株筛选到一株发生内生质粒消除的突变株MB287, 具有与野生菌株类似的锰耐受活性, 且对Mn (II)的氧化活性与野生菌株相比无明显改变, 表明野生菌株MB283中与锰抗性和锰氧化相关的基因可能是定位于该菌的染色体上。

Abstract:

A bacilli-shaped isolate with a unique dual manganese (II)-resistant and manganese (II)-oxidizing activities was screened from the yellow brown soil samples that collected in Queyu, Shandong Province, China. It exhibited a maximum manganese-resistant activity by 130 mmol/L of Mn (II), and a maximum manganese-oxidizing activity by 3.3 μmol/(L·d). This isolated was identified as a Bacillus megaterium strain (named as MB283) according to the morphological, physiological and biochemical characteristics, G + C content as well as the 16S rDNA sequence alignment analyses. Interestingly, the cell growth of MB283 was favored by the low concentration Mn (II) (10 mmol/L). A plasmid-cured mutant strain named as MB287 was obtained by perseveringly incubation of the strain at 43°C and supplementing additionally with 0.01% SDS. It was found that this mutant strain exhibited the proximate Mn (II)-resistant and Mn (II)-oxidizing activities compared to its wild-type strain. Thus, the results indicated that the corresponding genes of manganese resistance/oxidation in MB283 could locate in its chromosomal DNA.