Isolation, identification and biotransforming of Alcaligenes faecalis

Abstract:

[Background] Hydrogen sulfide (H₂S) is a toxic and harmful gas released in the process of livestock production, which seriously harmed the health of livestock and human beings. Therefore, the degradation of hydrogen sulfide, especially the transformation of hydrogen sulfide by biological oxidation, has become a current research focus. [Objective] In order to screen the highly efficient sulfur-oxidizing strains and study its biotransformation. [Methods] Using fresh feces collected from a chicken farm in Changchun city as the material, sulfur-oxidizing strains were isolated and identified. The growth conditions were optimized by using single-factor analysis, the biotransformation efficiency was studied, and the mRNA expression levels of soxY and soxZ genes were detected. [Results] A highly efficient sulfur-oxidizing strain, JF9, was successfully obtained, which was preliminarily identified as Alcaligenes faecalis. Optimal growth conditions:substrate concentration 0.5 g/L, temperature 35℃, initial pH 7.0. Under these conditions, the removal percentage of Na₂S was over 94%. The strain JF9 had soxY and soxZ genes, and their transcription levels were greatly induced by sulfur substrates (P<0.05). [Conclusion] The isolated strain Alcaligenes faecalis had a considerable ability to degrade sulfide, and the sulfur-oxidizing genes were highly expressed during the desulfurization process.