Diversity of Sulfur-Oxidizing Bacteria in Greenwater System of Coastal Aquaculture

Abstract

Reduced sulfur compounds produced by the metabolism are the one of the major problems in aquaculture. In the present study, herbivorous fishes have been cultured as biomanipulators for secretions of slime, which enhanced the production of greenwater containing beneficial bacteria. The genes encoding soxB which is largely unique to sulfur-oxidizing bacteria (SOB) due to its hydrolytic function has been targeted for examining the diversity of SOB in the green water system of coastal aquaculture. Novel sequences obtained based on the sequencing of metagenomic clone libraries for soxB genes revealed the abundance of SOB in green water system. Phylogenetic tree constructed from aligned amino acid sequences demonstrated that different clusters have only 82-93% match with Roseobacter sp., Phaeobacter sp., Roseovarius sp., Sulfitobacter sp., Ruegeria sp., and Oceanibulbus sp. The level of conservation of the soxB amino acid sequences ranged from 42% to 71%. 16S rRNA gene analyses of enrichment culture from green water system revealed the presence of Pseudoxanthomonas sp., which has 97% similarity with nutritionally fastidious Indian strain of Pseudoxanthomonas mexicana-a sulfur chemolithotrophic gamma-proteobacterium. Our results illustrate the relevance of SOB in the functioning of the green water system of coastal shrimp aquaculture for oxidation of reduced sulfur compounds, which in turn maintain the sulfide concentration well within the prescribed safe levels.

Sulphate production byParacoccus pantotrophusATCC 35512 from different sulphur substrates: sodium thiosulphate, sulphite and sulphide

“…Many genera of this group, including Acidianus, Acidithiobacillus, Aquaspirillum, Aquifer, Bacillus, Beggiatoa, Methylobacterium, Paracoccus, Pseudomonas, Starkeya, Sulfolobus, Thermithiobacillus, Thiobacillus and Xanthobacter are consecrated in the literature, presenting physiological and genetic machinery to control odors present in many environmental compartments as soil, marine estuaries, rice plantation, leached mining, hot springs, alkaline and hypersaline lakes [15,16,17,18].…”

Diversity and activity of sulphur-oxidizing bacteria and sulphate-reducing bacteria in landfill cover soils

“…The bio-oxidation of sulphide by most SOB generally contains the step of thiosulphate oxidation (Sievert et al 2007). One unique enzyme of the thiosulphate-oxidizing multienzyme complex in SOB is soxB, which contains a prosthetic manganese cluster in the reaction centre (Krishnani et al 2010). Additionally, SRB can use sulphate as the terminal electron acceptor during the degradation of organic matters under anaerobic conditions, producing H 2 S in landfills (Tang et al 2009).…”

“…The reduction of sulphite to sulphide, catalysed by siroheme dissimilatory sulphite reductase (DSR), is a key step of the dissimilatory sulphate reduction in SRB (Geets et al 2006). The genes of soxB and dsrB, encoding soxB and the b subunit of DSR, respectively, have been widely targeted to analyse the diversity and distribution of SOB and SRB in natural environments (Geets et al 2006;Krishnani et al 2010;Sorokin et al 2012). However, few data have been reported on activities and diversities of SOB and SRB in landfill cover soils despite the massive emission of H 2 S from landfills (Kim et al 2005;Plaza et al 2007).…”

Microbial metagenomics in aquaculture: a potential tool for a deeper insight into the activity

“…For instance, Krishnani et al . (,b) described the diversity of sulphur‐oxidizing bacteria in a green water system of coastal aquaculture; the authors documented the unexpected presence of Pseudoxanthomonas sp. (a sulphur chemolithotrophic γ‐proteobacterium).…”

“…In other research, Krishnani et al . (,b) collected microbe samples from coastal soils and used a set of degenerate primers to amplify various fragments of soxB genes involved in sulphur oxidation. In this experiment, metagenomics revealed that chemolitoautotrophy based on sulphur oxidation is sustained by the presence of sulphur oxidizers in coastal aquaculture.…”