Isolation And Characterization Of Glyphosate Degrading Bacterium G-6

Sixteen strains of glyphosate-degrading bacteria were isolated from 9 kinds of soil, which were collected from Huazhong Agricultural University. It was found that the strain G-6, had the best ability to degrade the phosphonate herbicide glyphosate when we determined the ability of the sixteen strains of glyphosate-degrading bacteria by HPLC. It showed 86.52% glyphosate degradation in 48 hours in 300 mmol/L glyphosate minimal medium. The sequence analysis of a 16S rDNA fragment amplified from total DNA of strain G-6 was used to identify G-6, the results showed that G-6 had 97.78% comparability with Pantoea agglomerans. Pantoea agglomerans, Enterobacter agglomerans, Erwinia winslow were the same object but had different names, G-6 was identified as Erwinia winslow. Associated with morphology, cultured characteristic, 16S rDNA fragment amplified and physio-biochemical characteristic, G-6 was identified as Erwinia stewartii.Glyphosate-tolerant test showed that, the best glyphosate-tolerant concentration was 300 mmol/L, the maximal glyphosate-tolerant concentration was over 500 mmol/L. Strain G-6 had wide acid and alkali adaptive range, could adapt to acid and alkali change in surroundings. Strain G-6 had growth from pH1 to pH12, had better growth from pH6.0 to pH8.0, had best growth at pH6.0. Addition of 0.02-0.2 mg/kg heavy metal ions Cd²⁺ and 400 mg/kg heavy metal ions Cu²⁺ could promote the degradation of glyphosate by G-6, but addition of heavy metal ions Pb²⁺, Zn²⁺, the degradation of glyphosate was inhibited. As a result, strain G-6 could degrade glyphosate in heavy metal ions polluted soil. Cyfluthrin and deltamethrin could also be degraded, the cyfluthrin degrading rate was 37.87% in 6 days, the deltamethrin degrading rate was 33.21% in 6 days.Soil glyphosate-degrading microorganisms were thousands upon thousands, the key was to find the strain had the best ability to degrade the glyphosate, had minimum influence by environment. And studied degrading enzyme and gene, cultivated glyphosate-tolerant and glyphosate-degrading transgenic crops. Crops catalyzed...