Soil Enzyme Activity, Microbial Functional Diversity And Aniline-degrading Microorganisms

The soil enzyme activities, nutrient content and microbial biomass and community functional diversity were investigated in long-term fertilizing soil sample which was come from Ecological Experimental Station of Red soil, Chinese Acedemy of Sciences.The result showed enzyme activities, nutrient content, microbial biomass and community functional diversity varied greatly among the treatments with application of different fertilizers. Soil urease and dehydrogense activity could be as a comprehensive index of soil fertility. After 20 years application of fertilizers for flooded double rice crops, the number of cultivable microorganisms was significantly larger, but fertilization result in microbial community diversity decrease as showed by Biolog results, and microbial biomass and community functional diversity and microbial species were higher in the treatments fertilized with P than those without P. Microbial community uniformity were higher in the treatment fertilized with straw manure than those without straw manure.2. Isolation and characterization of two kinds of bacterial strain for the degradation of aniline.Two kinds of aniline-degrading bacteria strains AN4,AN5. which were able to grow on aniline as nitrogen and energy sources, were isolated from the activated sluge drained from Nanjing chemical plant.We identified them as Flavobacterium strain AN4 and Rhodococcus strain AN5 respectively, according to morphological, physiological and its 16SrRNA gene sequence.The optimun temperature and pH value for growth and aniline degradation were 30℃and 7.0. Strain AN4 is capable of growing on aniline mediam with a concentration of higher than 3000mg/L. Under the suitable conditions, Strain AN4 can completely degrade aniline with 1000mg/L during 40h. And it can using phenol, nitrobenzene, benzoate as sole carbon and energy source. Strain AN5 is capable of aerobic and anaerobic degradation of aniline, and it can grow on aniline mediam with a concentration of higher than 5000mg/L. Strain AN5 can also grow using phenol, naphthalene, benzoate as sole carbon and energy source. At same time, we discovery that the addition of peptone to aniline minimal medium resulted in an acceleration of the aniline degradation rate, especially for strain AN4. Their aromatic degradation pathway is adapted to that of catechol 1,2-dioxygenase.