| 摘要 |
The present invention provides a mixed bacterial culture, designated as the culture Atz Mix 1, which originates from the soil exposed to long-term contamination with atrazine and other s-triazine compounds. The culture Atz Mix 1 degrades atrazine at various tempetaures (1O~C to 30~C) in a wide range of atrazine concentrations (several ppb to ten thousand ppm), without formation of toxic metabolites and leading to the complete atrazine degradation (mineralization). Atz Mix 1 is a stable mixed culture consisting of at least four members of different morphological, physiological and catabolic properties. Molecular characterization of the culture Atz Mix 1 showed the presence of catabolic genes trzN,atzB, atzC coding the enzymes for the degradation of atrazine to cyanuric acid and the gene trzD coding the enzymes for subsequent opening of s-triazine ring whereas high degree of mineralization of ring labelled [14C] atrazine (approximately 80%) confirmed that the degradation proceeded to yield CO2 and NH4 +. The microbiological method of degrading atrazine and other s-triazine compounds, which is part of the present invention, is advantageous over the so far described methods using individual bacterial cultures. This is primarily due to the specific growth and catabolic characteristics of the mixed culture Atz Mix 1 used as a biological agent, i.e. due to its capability to express sustained growth and atrazine- degrading efficiency under the conditions similar to those occurring in atrazine- contaminated environment (e.g. varying temperatures, low C/N ratio, presence of preferential nitrogen source, high atrazine concentrations). Furthermore, it should be emphasized that the inhibition of atrazine degradation in the presence of readily accessible nitrogen sources observed with majority of the so far described individual bacterial strains was not recorded with the culture Atz Mix 1. Accordingly, it can be expected that the microbiological method of the present invention will be suitable for remediation of atrazine-contaminated soils, even those rich in nitrogen, as well as for accelerating the process of atrazine mineralization in waste waters containing high concentrations of s-triazine compounds.
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