Assessment of Sulphate Reduction Bacteria in lisan soil and Brackish water, case study from lower Jordan Valley

Abstract

Jericho area is suffering from limited water resources and high salinity of groundwater about 348 gL-1 . The lack of sufficient water presents a serious challenge to the people in Jericho. This is the most important problem facing the agricultural sector in Jericho; so the use of desalination techniques is essential and present one of promising and important step to compact and manage these problems. Sulphide is a common constituent of many waste and saline water. The formation of sulphide upon reduction of sulphate and other sulphur containing compounds is one of the solutions by precipitating sulphur compounds. One method for that is using sulphate-reducing bacteria (SRB) to reduce sulphate. This study focuses on isolation of SRB from north of Jericho area, and measuring their efficiency in sulphate reduction from prepared standard sulphate solute in distilled water (with SO4 -2 concentration of 250mg/l), in order to use SRB in the future as a new tool for reducing salinity rather than expensive existing techniques. 2 Water and soil samples were collected from the north of Dead Sea area and SRB were isolated from the water and soil samples and cultured on a specific selective media (Postgate C media) under anaerobic conditions. Results showed isolation of four species of SRB, Two had PCR positive(With expected band size on gel electrophoresis) results , and the other two had PCR negative results (Two unknown bacterial isolates which not detected by universal primer have been used in this work without band on gel electrophoresis ). To confirm the isolated bacteria is SRB, Polymerase chain reaction (PCR) was used with specific primers to amplify 16S rDNA. For measuring the efficiency of isolated bacteria in sulphate reduction, bioreactor method was used. Results of this experiment indicate that isolated bacteria belong to SRB as was confirmed by PCR with specific primers to amplify 16S rDNA; it was identified as Desulfobacter latus strain PTUKS (MK829591) as being determined with 98% homology with Desulfobacter latus (GenBank accession Sequence ID is: gi|343201416|NR_042142.1) using BLAST analysis , the other was identified as Desulfovibrio vulgaris strain PTUKS (MK829604) as being determined with 99% homology with Desulfovibrio vulgaris (GenBank accession Sequence ID is: gi|77539416|AB237496.1 ) using BLAST analysis. 3 Bioreactor results showed that the reduction percentages of sulphate concentrations were higher than achieved by previous studies and reached to 43% reduction percentage for Desulfobacter latus strain PTUKS (MK829591).