Isolation, Identification And Characterization Of Atrazine-degrading Bacteria ADG1, AG1 And SA1

Bioremediation has advantages other pollution remediation methods absent. It has been an important research item for us to exploit and utilize microbial resource to remove environmental pollutions. In recent years, a large amount of unexploited microbial resources were detected by culture-independent microbiological molecular technology, which give us a hint that there are also many pollutant-degrading microbial resources untouched now. Atrazine has been widely used for a long time in the world, which lead to the pollution of a large area of soil, ground water and underground water. In this dissertation we tried to isolate degrading bacteria by the way different from enrichment isolation usually employed, to isolate dominant in situ atrazine-degrading bacteria from polluted soil, and studied their characteristics, degrading genes and applied them to remove atrazine in simulated pollution soil on the base of others' research achievements.1. Isolation and identification of high efficient atrazine-degrading bacteriaHigh efficient atrazine-degrading bacteria AG1, ADG1 and a consortium AH were isolated without enrichment by diluting and plating long time atrazine-contaminated soil samples(S1, S2, S3), which was collected from different area, directly onto plates containing soil extracts and atrazine. By repeated alternation of liquid cultivating and plate streaking for a long time, a pure atrazine-mineralizing bacterium strain SA1 was isolated from AH. AG1, ADG1 and SA1 all could degrade more than 500 mg ·L-1 of atrazine. Combined their 16S rDNA sequences analysis with physiobiochemical characteristics, AG1 and ADG1 were identified as Arthrobacter spp., and SA1 was Pseudomonas sp..2. Studies of growth and degradation characteristicsThe optimal carbon sources for AG1 were maltose, sucrose and mannitaol, and the optimal nitrogen source was organic nitrogen, and the most optimal C/N (mol atom) was 6/1. It grew well under conditions of 25℃-30℃ and pH7-10. Its resting cellsdegraded atrazine well at 25℃-42℃, and their degrading efficiency was not affected greatly by pH. AG1. Besides atrazine, AG1 could also grow on simazine, terbuthylazine, ametryn, simetryn and prometryn as sole nitrogen sources. AG1 could grow on atrazine as...