Anaerobic sulfur oxidation with acetylene as electron acceptor mediated by chemoautotrophic sulfur-oxidizing bacterium Halothiobacillus sp. LS2

Abstract:

[Objective] The study aims to investigate the acetylene as electron acceptor anaerobic sulfur oxidation mediated by the chemoautotrophic sulfur oxidizing bacterium Halothiobacillus sp. LS2. [Methods] Cell growth was measured by dilution coating method, SO₄^2- and S₂O₃^2- in sulfur oxidation kinetics were measured by ion chromatograph, and gene expression was analyzed based on relative fluorescence quantitative method. [Results] Although strain LS2 obtained high maximum reaction rate V_max with O₂ as electron acceptor, its growth with acetylene as electron acceptor under anaerobic condition was twice that with O₂ as electron acceptor, and the expression of soxB gene was significantly higher than that with O₂ as electron acceptor. [Conclusion] These results indicated that strain LS2 can not only complete anaerobic sulfur oxidation with acetylene as electron acceptor, but also has higher productivity efficiency than aerobic sulfur oxidation. In this study, an anaerobic sulfur oxidation reaction using acetylene as electron acceptor was proposed for the first time, which is of positive significance to the sulfur biogeochemical cycle.