Isolation And Identification Of Photosynthetic Bacteria And Their Decontamination Founction On Wastewater

In this thesis,8 Photosynthetic bacteria strains were isolated from the sediments and sewage. The 8 Photosynthetic bacteria strains were identified according to the morphology, cultural characteristics, cellular spectra physiological properties, inner intracytoplasmic membrane structures and carbon source utilization. Phylogenetic analyses were carried out on 2 strains. Isolated strains were used separately to study the sewage purification in different kinds of sewage.The 8 isolates which could not produce oxygen on the growth process were identified as Anoxygenic photosynthetic bacteria. The highest absorption peak is from 790nm to 1030nm, gram negative, photosynthetic pigments is bacteriochlorophyll a, cultures are gules brown or gules under anaerobic conditions, photosynthetic pigments are located in various types of intracytoplasmic membrane systems. These isolated strains were identified as Purple nonsulfur bacteriaStrain P063 and P064 can grow in media with up to 30g/L NaCl. The optimum pH is 6.5-7.5. Cultures are gules brown under anaerobic conditions. Intracytoplasmic membranes are vesicles, growth chemoheterotrophically in dark and aerobic conditions. These characteristics are accorded with those of genus Rhodobacter, These strains P063 and P064 were proposed as members of the genus Rhodobacter.Strain P061, P062, P065, P066, P067, P068 can’t grow in media with 30g/L NaCl. Cultures are gules under anaerobic conditions. Intracytoplasmic membranes are lamellar type,and the lamellae formed were extended parallel to the cytoplasma membrane and in the front of stacks. These characteristics are accorded with those of genus Rhodopseudomonas, Strains P063 and P064 were proposed as member of the genus Rhodopseudomonas.16S rDNA sequence determination and phylogenetic analysis were carried out for strains P061 and P064. The results indicated that strain P061 has the most closed relationship with Rhodopseudomonas palustris with the similantity of 98.56%. So it should belong to Rhodoseudomonas. Strain P064 has the most closed relationship with Rhodobacter sphaeroidesy and the similarity is 98.81%. So it should belong to Rhodobacter. Pure cultures of strains were immobilized adopting sodium alginate, the results showed that strain P067 has the highest sewage purification ability and the COD removal rate is 91.0% at 7 days. This strain adapts to complicated water, but it is sensitive to salinity. It has worse purification effect in salinity wastewater. Strains P066 and P068 can be fit for low-salt environment. They adapt to treat the sewage with high COD and high salinity. Strain P064 performed well in organic wastewater treatment.