| A strain of anaerobic purple sulfur bacteria was isolated in pure culture from the backwater and sludge of the Fu-nan-he river. Single cells were spherical to ovoid-shaped and their diameter were 1.5 to 2.5 μ m. The cells of this organism were Gram-negative. The photopigments consist of Bacteriochlorophyll a and carotenoids. Sulfide and thiosulfate were used as electron donors during photolithotrophic growth under anoxic conditions, while carbon dioxide was utilized as carbon source. Acetate, pyruvate, malate, rumarate, succinate, glucose, fructose, glycerol, ethanol and mannitol were photoassimilated in the presence of hydrogen sulfide.Optimum growth rates were obtained at PH 7.0~7.5, 28~30℃. The appropriate illumination intensity for this photosynthetic bacteria growth was about 1000-1500 1.x. During growth on sulfide, small sulfur globules were formed inside the cells or deposited extracellularly. Chemotrophic growth under microoxic conditions in the dark was possible. The G-KZ content of the DNA was 64.47 mol%. According to the structure of cells, biochemistry and physiology characteristics, and the photosynthetic reaction center, this strain of photosynthesis bacteria was identified as Thiocapsa roseopersicina.Under the optimum growth conditions, with about 10% inoculum of this bacterium, about 60 similar to 75% of the sulfide could be removed in 40-50 days. The experiments of applying sulfur-oxidizing bacteria on vegetable was also carried out. The results showed that the pure cultural bodies of the phodospirillaceae culturedunder light had obvious yield increasing effect. They could improve vegetable quality at the same time.
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