厌氧生境体系中产氢产乙酸细菌的FISH定量解析

Quantitative use of fluorescence in situ hybridization to detect syntrophic acetogenic bacteria in anaerobic environmental samples

摘要:

产氢产乙酸细菌是一类在有机物厌氧降解过程中起重要作用的细菌。以基于16S rRNA序列设计的特异性寡核苷酸探针为基础,优化FISH实验条件,确定该技术检测产氢产乙酸细菌的实验条件为样品固定19h、乙醇脱水5min,杂交缓冲液中甲酰胺浓度55%。运用建立的FISH技术检测了几种厌氧消化体系中产氢产乙酸细菌的数量,并与用传统MPN方法的结果进行了比较。结果表明,产氢产乙酸细菌分布广泛,废水处理UASB反应器和动物消化道,特别是反刍动物瘤胃中的产氢产乙酸细菌数量较高,其丰度分别为1.70×10⁹ cells/mL样品,6.50×10⁸ cells/mL样品。湖底沉积物中产氢产乙酸细菌数量较少,仅占整个微生物群落的0.4%,含量为1.20×108 cells/mL样品。

Abstract:

Syntrophic acetogenic bacteria, an important functional one in anaerobic habitats, were detected and counted by fluorescence in situ hybridization (FISH) technology by using 16S rRNA-based oligonucleotide probes. For enumeration and quantification of the targeted bacteria, an attempt was made to optimize the hybridization conditions. The optimum conditions are as follows: a fixation time of 19h, a dehydrated time of 5min, and a formamide concentration of 55% in hybridized solution. The abundance of syntrophic acetogenic bacteria of different environmental samples were quantified by FISH and the results showed that Upflow Anaerobic Sludge Reactor (UASB) treating STHZ〗high-concentration organic wastewater and the digestive tract of some animals were the main habitats of syntrophic acetogenic bacteria. The numbers of syntrophic acetogenic bacteria in UASB and cattle manure were 1.70×10⁹ cells/mL sample and 6.50×10⁸ cells/mL sample, respectively. Meanwhile, the sediments of rivers and lakes existed less of the bacteria and the contents of them were just about 1.20×10⁸ cells/mL sample in Taihu lake.