Isolation and chacterization the purple sulfur bacteria strains removing highest sulfide concentration from contaminated shrimp ponds in Thua Thien Hue Province

Abstract

The feasibility of using purple sulfur bacteria to remove sulfide from micro-aerobic-light waste treatment effluent was investigated. The 2 sulfur reducing bacteria DL11 and PH21 were recovered from waste of the intensive culture system of Litopenaeus vannamei in Thua Thien Hue. The isolated strains-DL11 and PH21 were Gram-negative, rods and high growth rate in medium containing sulfide. Molecular characterization of the 16S rRNA gene of strains DL11 showed an identity of 100% with Allochromatium humboldtianum (EU442182), whereas strain PH21 showed an identity of 100% with Marichromatium fluminis (FM210274). Moreover, results showed that these 2 bacteria can be effectively used for sulfide removal. The high removal efficiencies of 94.4% were obtained at 5 mg.L-1 of both strains and 40% for PH21 strain at 30 mg.L-1 provide advancement in the study of reducing sulfide concentration and may play putative functions in the improve water quality of aquaculture. Effect of pH and salinity on growth of 2 isolated strains also were determined. Keywords: 16S rRNA Allochromatium humboldtianum Marichromatium fluminis pH salinity