Kande Ramesh, Rajkumar Karthik, Anoor Pawan Kumar, Naik Srinivas, Burgula Sandeepta
Department of Microbiology, Osmania University, Tarnaka, Hyderabad, 500007, India.
GM Reddy Center for Plant Molecular Biology, Osmania University, Tarnaka, Hyderabad, 500007, India.
Braz J Microbiol. 2024 Dec;55(4):4101-4114. doi: 10.1007/s42770-024-01497-6. Epub 2024 Sep 2.
Extensive Monocrotophos (MCP) application in agricultural soils has led to its ubiquitous accumulation in the environment. Human health can be adversely affected by chronic exposure to produce and water from such areas, causing endocrine dysfunction, birth defects, blood and nervous disorders. This study investigated the possibility of detecting Monocrotophos-degrading bacteria in soil samples taken from a cotton cultivation field in a local area. We isolated a consortium that could tolerate and neutralize Monocrotophos upto a concentration of 2000 ppm. The consortium on 16 S rRNA sequencing were identified as Micrococcus luteus SBR2, Rhodococcus SBR5, Bacillus aryabhattai SBR8, Ochrobactrum intermedium SBK2. Significant tolerance of individual strains in the range of 500-5000 ppm was observed when incubating them in vitro with Monocrotophos in minimal salt medium. An analysis of the degrading genes opdA, mpd, and opd revealed plasmid borne opdA and mpd in the O.intermedium strain and B.aryabhattai strain. All the strains indicated genomic opdA and mpd whereas opd was not detected in plasmid or genomic DNA. The HPLC showed no peak at 2.5 min, when individual strains were incubated with Monocrotophos. The HPLC analysis of soil samples incubated with the consortium for two weeks showed complete degradation of Monocrotophos. GC-MS analysis confirmed that Monocrotophos and its solvent cyclohexamide were degraded into non-toxic compounds such as cyclotrisiloxane compounds, acetic acid, and others. This study indicates that the expression of organophosphate hydrolyzing enzymes in the consortium can greatly contribute to the neutralization of organophosphorus compounds and also serve as a bioremediation method for agricultural soils.
久效磷（MCP）在农业土壤中的大量施用导致其在环境中普遍积累。长期接触此类地区的农产品和水会对人类健康产生不利影响，导致内分泌功能障碍、出生缺陷、血液和神经紊乱。本研究调查了从当地一个棉花种植田采集的土壤样本中检测久效磷降解菌的可能性。我们分离出了一个能耐受并中和浓度高达2000 ppm久效磷的菌群。对该菌群进行16S rRNA测序后，鉴定为藤黄微球菌SBR2、红球菌SBR5、阿耶波多芽孢杆菌SBR8、中间苍白杆菌SBK2。当在最低盐培养基中与久效磷进行体外培养时，观察到各菌株在500 - 5000 ppm范围内具有显著耐受性。对降解基因opdA、mpd和opd的分析表明，中间苍白杆菌菌株和阿耶波多芽孢杆菌菌株中存在质粒携带的opdA和mpd。所有菌株均显示有基因组opdA和mpd，而在质粒或基因组DNA中未检测到opd。当各菌株与久效磷一起培养时，高效液相色谱（HPLC）在2.5分钟处未出现峰。用该菌群培养两周的土壤样本的HPLC分析表明久效磷已完全降解。气相色谱 - 质谱联用（GC - MS）分析证实久效磷及其溶剂环己酰胺已降解为无毒化合物，如环三硅氧烷化合物、乙酸等。本研究表明，该菌群中有机磷酸水解酶的表达可极大地促进有机磷化合物的中和，也可作为农业土壤的生物修复方法。
