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首页> 外文期刊>African Journal of Biotechnology >Isolation and characterization of two malathion-degrading Pseudomonas sp. in Egypt
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Isolation and characterization of two malathion-degrading Pseudomonas sp. in Egypt

机译：两种马拉硫磷降解假单胞菌的分离和鉴定。在埃及

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Pseudomonas aeruginosa and Pseudomonas mendocina degrading malathion were studied. Morphological, biochemical and 16S rRNA genes for bacterial identification were selected. Biodegradation of some organophosphorus compounds with the 2 bacterial isolates was determined by high performance liquid chromatography (HPLC). P. aeruginosa strain completely removed diazinon, malathion and fenitrothion, but not chlorpyrifos within 14 days. P. mendocina strain was not able to degrade malathion, diazinon and chlorpyrifos completely and no significant degradation for chlorpyrifos. The bacterial growth curve showed a steady increase in the two bacterial isolates masses during malathion degradation. The highest growth rates were with yeast extract, glucose and citrate for the 2 isolates, but not with phenol. Shaked high inoculum density with incubation at 30°C of malathion bacterial cultures were found to be the optimum conditions for malathion degradation. Bacterial culture extracts subjected to liquid chromatography/mass spectrometry (LC/MS) analysis revealed that the separated products were malathion monocarboxylic acid and malathion dicarboxylic acid. Molecular characterization of carboxylesterase enzyme revealed that carboxylesterase amino acid sequences of the 2 isolates showed high identity to other carboxylesterase enzymes of P. aeruginosa and P. mendocina, respectively. Phylogenetic analysis showed that P. aeruginosa was localized in a separate branch from other carboxylesterase producing Pseudomonas sp. So, it is suggested that this enzyme is a novel esterase enzyme. Use of pesticide-degrading microbial systems for removal of organophosphorus compounds from the contaminated sites requires an understanding of ecological requirements of degrading strains. The results provided an important insight into determining the bioremediation potential of both strains. But the mentioned bacteria cannot be the aim of bioremediation due to risk of public health hazard, hence these bacteria cannot be used in bioremediation but their purified enzymes could.
机译：研究了铜绿假单胞菌和mendocina假单胞菌降解马拉硫磷的情况。选择用于细菌鉴定的形态学，生化和16S rRNA基因。通过高效液相色谱（HPLC）测定了2种细菌分离物对某些有机磷化合物的生物降解。铜绿假单胞菌菌株在14天内完全清除了二嗪农，马拉硫磷和杀nitro硫磷，但没有毒死rif。 Mendocina菌株不能完全降解马拉硫磷，二嗪农和毒死rif，毒死and也无明显降解。细菌生长曲线显示马拉硫磷降解期间两个细菌分离物的质量稳定增加。两种提取物中酵母提取物，葡萄糖和柠檬酸盐的生长速率最高，而苯酚则没有。发现在30°C孵育马拉硫磷细菌培养物时摇动的高接种密度是马拉硫磷降解的最佳条件。进行了液相色谱/质谱（LC / MS）分析的细菌培养物提取物表明，分离出的产物为马拉硫磷一元羧酸和马拉硫磷二元羧酸。羧酸酯酶的分子特征表明，这两个分离物的羧酸酯酶氨基酸序列分别与铜绿假单胞菌和门氏假单胞菌的其他羧酸酯酶显示高度同一性。系统发育分析表明铜绿假单胞菌位于与其他羧化酶产生假单胞菌菌种不同的分支中。因此，建议该酶是一种新型酯酶。使用农药降解微生物系统从受污染场所去除有机磷化合物需要了解降解菌株的生态要求。结果为确定两种菌株的生物修复潜力提供了重要的见识。但是由于存在危害公共健康的风险，上述细菌不能作为生物修复的目标，因此这些细菌不能用于生物修复，但是可以纯化它们的酶。

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