The Primary Study On The Isolation, Determination And Product Of Photosynthetic Bacteria And Nitrifying Bacteria

Aiming directly at the recent widespread problems in the product of photosynthetic bacterium and nitrifying bacterium such as few high productive flora and immature technology of automatic cultivation, we investigated the isolation and identification of the strains and the bioreactor, consequently we got the formula of productive strains with better property and designed the bioreators. The study provided good theoretical and practical basis for the development of product in these two kinds of microorganism. The results of the study are as follows:1. 27 strains of photosynthetic bacterium, 4 strains of sub-nitrifying bacterium and 2 strains of nitrifying bacterium were enriched and isolated from seven specimens in different circumstances and initially identified.2. Two formulas with better production property, i.e. photosynthetic bacterium A and nitrifying bacterium E, were selected and obtained. The efficiency and security evaluated test showed that:(l) formula A, E and A+E (A and E mixed with equal ratio) were of no toxicity, furthermore, the Non-iron Ammonia acute toxic test showed that they had detoxification in different degrees. In 24hr LD50, 8 percent of formula A, E and A+E reduced the mortality of Gambusia affinis from 50% to 28.3%, 8.3% and 10.0% respectively. (2) Growth promotion simulated test showed that the three formulas could prompt growth and decrease mortality in different degrees when feed contaminated was in sub-favourable state. The length growth rates of the Larval carps (35cm) in 15ppm concentration of formula A, E and A+E were 26.3%, 22.0% and 32.5% respectively, higher than 4 controls in different grades. (3) The effect of formula in' middle-scale production manifested that formulas had obvious fundction in improving and purifying the quality of water. (4) The manufacturing cost of the selectedphotosynthetic bacterium medium was reduced effectively without changing production property and the selected nitrifying bacterium medium increased OD520 from 0.7~0.8 to over 1.1.3. Two novel photo-bioreactor and nitrifying bacterium bioreactor were tentatively designed. (1) Making use of the flashing light effect, applied the phenomenon of average light saturation into the photobioreactor, we utilized mechanical method to eliminated light-covered phenomenon caused by photosynthetic bacterium's attachment to the wall and designed clean-and-scrub stirred tank photo-bioreactor whose surface-to-volum ratios was 10m-1,below other reports significantly. The result showed that using photo-bioreactor in formula A could increase OD520 to 1,758 after cultivation for 48h. In contrast, growth rate of formula A in static culture was extremely slow. Moreover in batches culture, clear-and-scrub culture could improve growth rate 2 times than that of bacterium cultured with no clear-and-scrub. In successively culture with photo-bioreactor, the dilution rate was 0.04167h-1. The effect was satisfied. The results of the experiments provided experimental basis in the research of photo-bioreactor for large-scale and automatic cultivation of photosynthetic cells. (2) we determined the parameters of nitrifying bacterium reactor, designed air-lift nitrifying bacterium bioreactor and tested it's effect. The result showed that the OD52o of nitrifying bacterium cultured in bioreactor after 10 days could arrive a high level (1.641). The result provided basis for nitrifying bacterium's intermittent-flowing adding and mixed series fermentation.