Optimization for Culturing Rhodopseudomonas palustris and Studies on Its Capability of Removing Ammonia Nitrogen from Water System

The medium for culturing Rhodopseudomonas palustris is optimized and its capability of removing ammonia nitrogen from water system is studied.The results show that Rhodopseudomonas palustris has the ability to utilize many kinds of carbon sources and nitrogen sources and it is best to culture Rhodopseudomonas palustris in laboratorial experiments with lactic acid as carbon source and oxammite as nitrogen source,respectively.Results also indicate that concentration of carbon source and ratio of carbon source to nitrogen source are main factors that influence the growth of Rhodopseudomonas palustris,whereas concentration of potassium dihydrogen phosphate has not remarkable effects on the growth of this photosynthetic bacterium.From the result of orthogonal experiment,it is suggested that keeping concentration of lactic acid at 1 %,ratio of carbon source to nitrogen source at 1.5 and concentration of potassum dihydrogen phosphate at 1.5 g/L is suitable to culture this photosynthetic bacterium.It is seen from batch culture experiments with optimized medium and under 30 ℃ and nature lighting condition that lag phase of this photosynthetic bacteria is between 0 to 2 d,exponential phase is between 2 d to 10 d,stationary phase is between 10 d to 20 d.Rhodopseudomonas palustris is superior to other investigated microbial community with regard to the capability of removing ammonia nitrogen,but its capability of removing ammonia nitrogen strongly depends on the water quality of the sample and is not stable.