Identification and characterization of a sulfur-oxidizing bacterium B1-1 isolated from the sediment of marine cage culture area

Abstract:

[Background] Marine cage culture is a high-density and high feeding artificial breeding method. Sulfide pollution in marine cage culture environment seriously restricts the economic benefits and sustainable development of aquaculture. [Objective] The identification and analysis of the oxidation characteristics of sulfur-oxidizing bacterium B1-1 from the sediment of marine cage culture area, is to provide theoretical basis for sulfide pollution control of sediment in the marine cage culture area. [Methods] The species of strain B1-1 were identified by a variety of methods including Gram staining, plate colony morphologic observation, morphological characteristics research, 16S rRNA gene sequence analysis and the molecular phylogenetic tree construction. The optimal culture conditions (pH, temperature, substrate concentration, additional carbon and nitrogen source, and metal ion) for the oxygenation of strain B1-1 were determined. [Results] Strain B1-1 was Gram-negative, short rod and identified as Halothiobacillus hydrothermalis (Genbank accession number: KU362926). The optimal culture conditions for strain B1-1 in the shaking flasks were pH 8.0, 30 °C, and substrate concentration 5.0 g/L. The additional carbon source did not change the oxidation ability of strain B1-1. With the additional ammonium salt, such as ammonium sulfate and ammonium oxalate, the delay period could be shortened to 12 h. Besides, the addition of Mg2+ could significantly improve oxidation ability of strain B1-1, the oxidation rate could reach 100%. [Conclusion] Based on the high haloduric ability and the high ability of oxidation rate of the sodium thiosulfate, Halothiobacillus hydrothermalis B1-1 is of potential in the fields of bioremediation of polluted marine cage culture area.