Diversity of Hydrogen Sulfide Oxidizers in Biogas-Stream Fed Bioscrubber in Seafood Factory

Abstract

Corrosive and harmful hydrogen sulfide (H2S) are major obstacles to biogas utilization. Bioscrubber system is the one of the most popular tecnologies for removing H2S from biogas. Sulfur oxidizing bacteria (SOB) play an important role in controlling the efficiency and stability of bioscrubber systems through sulfur oxidation (soxABXYZ) and flavocytochrome sulfide dehydrogenase (fccAB) enzyme catalyses. The main purpose of this research is to analyse microbial diversity and gene expression pattern of SOBs related to H2S oxidation. In this study, SOB population were collected from the full-scale bioscrubber system of the seafood factory (TKF). The richness and diversity of SOB strains were analyzed using next-generation sequencing analysis (NGS) based on 16S rRNA gene. DNA microarray was used to examine the expression of soxABXYZ and fccAB genes involved in the H2S oxidation. A number of readable sequences indicate SOB diversity and richness that cover the entire population of bacteria in the TKF factory. The phylum proteobacteria was found covered up to 60% of total bacteria. Interestingly, the highest abundance genus of SOB coexisting in biocrubber to oxidize H2S in biogas was Pseudomonas, MWH-UniP1_aquatic, Smithella, Thioalkalimicrobium, Hydrogenophaga and Acinetobacter. Paracoccus sediminis, Pseudomonas stutzeri and Paracoccus denitrificans were found having the soxAXYZ and soxB gene expression level up to 0.2754-fold, 0.0808-fold and 0.3819-fold respectively. On the other hand, the expression of fccAB genes of P. denitrificans was increased up to 0.3819-fold. Altogether, the predominance of these species-strains was associated with the excellent H2S removal efficiency of 99.3% in the TKF factory.