| 1.Isolation and identification of organophosphorous pesticides degrading bacteriumTo search for microorganisms that could degrade organophosphorous pesticides with high efficiency, a bacterial strain, coded JS018, was isolated by screening potential bacteria from the soil in the vicinity of Shanming Pesticides Factory, Shanming, Fujian. Laboratory tests showed that the bacterium could degrade several kinds of organophosphorous pesticides, such as Parathion-methyl, phoxin and hostathion. The bacteria colonies on LB plate appeared shiny and pale-pink in color. The bacteria were Gram-negative coccoids, 0.5~0.7μm in diameter . They grew well at 30- 38℃ and pH7.0-9.0. The optimal temperature and pH for cell growth were 32℃ and 7.5-8.0, respectively. They did not grow in media containing 6% or more NaCl.The antibiotic susceptibility tests showed that the strain was resistant to ampicillin, penicillin and lincomycin. It was sensitive to kanamycin, tetracycline and gentamicin. Laboratory tests also showed that the strain could ferment D-glucose, trehalose, melezitose and ethanol. It was negative in the production of indole and hydrogen sulfide. It could not liquefy gelatin, utilize citrate, nor ferment L-arabinose, sucrose, D-mannitol, D- xylose, fructose, D-galactose, maltose or lactose. The bacteria showed an ability to reduce nitrate and the activities of catalase and urease. Based on its morphological, physiological and biochemical properties, as well as the 16S rDNA sequence analysis results, the strain was tentatively identified as Roseomonas sp.Genus Roseomonas include six genomospecies, of which three have been named. Based on the result of 16S rDNA sequence analysis, the homology between JS018 and Roseomonas genomospecies 4 was 99%, but the physiological and biochemical properties of the strain was different from six genomospecies in esculin hydrolysis, D-mannose and D-glucose oxidation. None of Roseomonas sp has been reported in... |
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