Crop Production and Protection Division, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow 226015, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
Crop Production and Protection Division, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow 226015, India.
Pestic Biochem Physiol. 2024 Aug;203:105989. doi: 10.1016/j.pestbp.2024.105989. Epub 2024 Jun 13.
The present study focused on the isolation and identification of CP and TCP bacteria degrading bacteria from the rhizospheric zone of aromatic grasses i.e. palmarosa (Cymbopogon martinii (Roxb. Wats), lemongrass (Cymbopogon flexuosus) and vetiver (Chrysopogon zizaniodes (L.) Nash.). So that these isolates alone or in combination with the vegetation of aromatic grasses will be used to clean up CP-contaminated soils. The study also explored enzymatic activities, CO release, dechlorination potential, and degradation pathways of bacterial strains. A total of 53 CP-tolerant bacteria were isolated on their physical characteristics and their ability to degrade CP. The ten highly CP-tolerant isolates were Pseudomonas aeruginosa Pa608, three strains of Pseudomonas hibiscicola R4-721 from different rhizosphere, Enterococcus lectis PP2a, Pseudomonas monteilii NBFPALD_RAS131, Enterobacter cloacae L3, Stenotrophomonas maltophilia PEG-390, Escherichia coli ABRL132, and Escherichia coli O104:H4 strain FWSEC0009. The CO emission and phosphatase activities of the isolates varied from 3.1 to 8.6 μmol mL and 12.3 to 31 μmol PNP h, respectively in the CP medium. The degradation kinetics of CP by these isolates followed a one-phase decay model with a dissipation rate ranging from 0.048 to 0.41 d and a half-life of 1.7-14.3 days. The growth data fitted in the SGompertz equation showed a growth rate (K) of 0.21 ± 0.28 to 0.91 ± 0.33 d. The P. monteilii strain had a faster growth rate while E. coli ABRL132 had slower growth among the isolates. The rate of TCP accumulation calculated by the SGompertz equation was 0.21 ± 0.02 to 1.18 ± 0.19 d. The Pseudomonas monteilii showed a lower accumulation rate of TCP. Among these, four highly effective isolates were Pseudomonas aeruginosa Pa608, Pseudomonas monteilii NBFPALD_RAS131, Stenotrophomonas maltophilia PEG-390, and Pseudomonas hibiscicola R4-721. Illustrations of the degradation pathways indicated that the difference in metabolic pathways of each isolate was associated with their growth rate, phosphatase, dehydrogenase, oxidase, and dechlorination activities.
本研究从芳香草根际区（如香茅（Cymbopogon martinii (Roxb. Wats）、柠檬草（Cymbopogon flexuosus）和香根草（Chrysopogon zizaniodes (L.) Nash.））中分离和鉴定了能够降解 CP 和 TCP 的细菌。这些分离物可以单独或与芳香草植被一起用于清理 CP 污染的土壤。该研究还探索了细菌菌株的酶活性、CO 释放、脱氯潜力和降解途径。根据它们的物理特性和降解 CP 的能力，共分离出 53 株 CP 耐受细菌。从不同根际分离出的 10 株高度耐受 CP 的分离物为铜绿假单胞菌 Pa608、3 株假单胞菌 hibiscicola R4-721、粪肠球菌 PP2a、假单胞菌 monteilii NBFPALD_RAS131、阴沟肠杆菌 L3、嗜麦芽寡养单胞菌 PEG-390、大肠杆菌 ABRL132 和大肠杆菌 O104:H4 菌株 FWSEC0009。这些分离物在 CP 培养基中的 CO 排放和磷酸酶活性分别为 3.1 至 8.6 μmol mL 和 12.3 至 31 μmol PNP h。这些分离物对 CP 的降解动力学遵循单相衰减模型，耗散率为 0.048 至 0.41 d，半衰期为 1.7 至 14.3 d。生长数据符合 SGompertz 方程，表明生长率（K）为 0.21±0.28 至 0.91±0.33 d。其中，假单胞菌 monteilii 的生长率较快，而大肠杆菌 ABRL132 的生长率较慢。通过 SGompertz 方程计算的 TCP 积累速率为 0.21±0.02 至 1.18±0.19 d。假单胞菌 monteilii 显示出较低的 TCP 积累率。其中，4 株高效分离物为铜绿假单胞菌 Pa608、假单胞菌 monteilii NBFPALD_RAS131、嗜麦芽寡养单胞菌 PEG-390 和假单胞菌 hibiscicola R4-721。降解途径的说明表明，每个分离物的代谢途径差异与其生长率、磷酸酶、脱氢酶、氧化酶和脱氯活性有关。
