Isolation of Photosynthetic Bacteria from Coal Mining Site Having Potential for Nitrate Removal

Abstract

Wastewater is untreated water that has high amount of nutrients such as nitrate, phosphate, ammonium and chemical oxygen demand (COD). When it is discharged into watercourse, it affects human and aquatic biota. The application of photosynthetic bacteria is considered bio-friendly system than the conventional one. Hence, the present study investigates the effectiveness of robust strain of photosynthetic bacteria for nitrate removal under different concentrations of 85, 135, 190, 235 and 320 mg/L. Serial dilution techniques was used for the isolation of the bacteria. The results showed that three bacterial isolate were obtained and were both screened for nitrate reduction ability. The isolate was able to remove 91, 90, 71, 67 and 55% of nitrate at 85, 135, 190, 235 and 320 mg/L respectively. The bacteriochlorophyll of the isolate was detected at peak range between 689-710 nm. The morphological, physiological and biochemical characterization showed that the isolate was identified as Rhodopseudomonas sp. The nutrient removal yield of the nitrate under different concentrations was found to be at range of 0.01- 0.033 g-1 DCW g-1 NO3.- This study suggested that the strain could be used as an efficient bacterial candidate for the treatment of wastewater containing high amount of nitrate.