硫代硫酸盐氧化菌TX的分离、鉴定及其生物学特性

Isolation,Identification and Characterization of Thiosulfate-oxidizing Bacterium TX

从聚硫橡胶废水处理系统中分离到一株硫代硫酸盐氧化细菌TX。根据其形态学特征、生理特征和16S rRNA基因序列相似性分析,将该菌株初步鉴定为盐生硫杆菌属(Halothiobacillus sp.)(GenBank登录号为EU871645)。该菌株能利用硫代硫酸盐、单质硫、连四硫酸盐、硫化物或亚硫酸盐为唯一能源进行自养生长,不能利用葡萄糖、蔗糖、果糖、乳糖、麦芽糖或酵母粉进行异养生长,为专性化能无机自养型硫杆菌。在以硫代硫酸钠为唯一能源的培养基中其最适生长温度为30°C^35°C,最适起始pH值为3.0~5.0。在矿物盐培养基中,硫代硫酸盐最终被氧化成硫酸,造成培养基pH持续下降。在摇瓶分批培养和硫胶废水处理过程中均检测到连四硫酸盐的积累,表明该菌株主要通过连四硫酸盐途径或"S4I"途径进行硫代硫酸盐的生物氧化。

A thiosulfate-oxidizing bacterium TX was isolated from polysulfide wastewater treatment system. It was preliminarily identified as Halothiobacillus sp. according to its morphological, physiological properties and similarity analysis of 16S rRNA gene sequence （GenBank accession No. EU871645）. This bacterium was an obligate chemolithoautotrophic sulfur-oxidizing bacterium since it could utilize thiosulfate, elemental sulfur, tetrathionate, sulfide or sulfite as sole energy source but did not show growth on the medium with glucose, sucrose, fructose, lactose, mannose or yeast extract as sole carbon source. The optimal growth condition for thiosulfate oxidation was 30℃-35℃ and pH 3.0-5.0 respectively. Significant reduction in medium pH from 4.0 to 1.2 was observed due to oxidation of thiosulfate to sulfate during the batch culture incubation period. During the course of thiosulfate oxidation accumulation of tetrathionate was observed either in synthetic medium or in the mixed liquor from aeration tank of the polysulfide wastewater treatment system. This indicates that the ＂S4 intermediate （S4I）＂ pathway was responsible for thiosulfate oxidation in this bacterium.