Butyrate is one of the most important intermediates during anaerobic digestion of protein wastewater, and its oxidization is considered as a rate-limiting step during methane production. However, information on syntrophic butyrate-oxidizing bacteria (SBOB) is limited due to the difficulty in isolation of pure cultures. In this study, two anaerobic chemostats fed with butyrate as the sole carbon source were operated at different dilution rates (0.01/day and 0.05/day). Butyrate- and acetate-oxidizing bacteria in both chemostats were investigated, combining DNA-Stable Isotope Probing (DNA-SIP) and 16S rRNA gene high-throughput sequencing. The results showed that, in addition to known SBOB, Syntrophomonas, other species of unclassified Syntrophomonadaceae were putative butyrate-oxidizing bacteria. Species of Mesotoga, Aminivibrio, Acetivibrio, Desulfovibrio, Petrimonas, Sedimentibacter, unclassified Anaerolineae, unclassified Synergistaceae, unclassified Spirochaetaceae, and unclassified bacteria may contribute to acetate oxidation from butyrate metabolism. Among them, the ability of butyrate oxidation was unclear for species of Sedimentibacter, unclassified Synergistaceae, unclassified Spirochaetaceae, and unclassified bacteria. These results suggested that more unknown species participated in the degradation of butyrate. However, the corresponding function and pathway for butyrate or acetate oxidization of these labeled species need to be further investigated.

中文翻译：

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通过基于DNA的稳定同位素探测，确定在由丁酸盐喂养的中温厌氧性化粪池中的新型丁酸盐和乙酸盐氧化细菌。

丁酸是蛋白质废水厌氧消化过程中最重要的中间体之一，其氧化被认为是甲烷生产过程中的限速步骤。但是，由于难以分离纯培养物，因此关于合成型丁酸氧化细菌（SBOB）的信息有限。在这项研究中，以丁酸盐作为唯一碳源的两个厌氧化学恒温器以不同的稀释率（0.01 /天和0.05 /天）运行。结合两个DNA稳定同位素探测（DNA-SIP）和16S rRNA基因高通量测序，研究了两个化学恒温器中的丁酸和乙酸氧化细菌。结果表明，除已知的SBOB，Syntrophomonas外，其他未分类的Syntrophomonadaceae属均为假定的丁酸氧化细菌。Mesotoga，Aminivibrio，Acetivibrio，Desulfovibrio，Petrimonas，Sedimentibacter，未分类的厌氧细菌科，未分类的增效科，未分类的螺旋藻科和未分类的细菌可能会导致丁酸酯代谢中的乙酸氧化。其中，丁二酸杆菌属，未分类的增效科，未分类的螺旋藻科和未分类的细菌的丁酸盐氧化能力尚不清楚。这些结果表明，更多的未知物种参与了丁酸的降解。但是，这些标记物质的丁酸酯或乙酸酯氧化的相应功能和途径需要进一步研究。丁二酸杆菌属，未分类的增效科，未分类的螺旋藻科和未分类的细菌的丁酸盐氧化能力尚不清楚。这些结果表明，更多的未知物种参与了丁酸的降解。但是，这些标记物质的丁酸酯或乙酸酯氧化的相应功能和途径需要进一步研究。丁二酸杆菌属，未分类的增效科，未分类的螺旋藻科和未分类的细菌的丁酸盐氧化能力尚不清楚。这些结果表明，更多的未知物种参与了丁酸的降解。但是，这些标记物质的丁酸酯或乙酸酯氧化的相应功能和途径需要进一步研究。