Biodegradation of phthalate esters using efficient microorganisms
| dc.contributor.advisor | Livleen Shukla | |
| dc.contributor.author | DHARMENDRA KUMAR | |
| dc.date.accessioned | 2019-12-02T06:54:05Z | |
| dc.date.available | 2019-12-02T06:54:05Z | |
| dc.date.issued | 2019 | |
| dc.description | T-10152 | en_US |
| dc.description.abstract | The present study was carried out for isolation, identification and characterization of DEP and DEHP degrading bacteria from Centre for Cultivated Protection Technology (CPCT) IARI, New Delhi. Phthalate esters are categorized according to their molecular weight. DEHP is classified as higher molecular weight esters while DEP as low molecular weight. Both the PAEs are well-known xenobiotics and recalcitrant nature. Phthalate esters and their metabolites are known to exhibit carcinogenic action and also found to be endocrine disruptors and produce adverse reproductive, neurological and immune effect in both human and wildlife. In solving the serious problems of pollution caused by phthalate esters, it is important to assess the potential of bacterial strains indigenous to sites, contaminated with phthalate esters for their ability to degrade DEP and DEHP. The eleven bacterial isolates were identified through 16S rDNA sequencing, which grew well at 500 ppm of DEP and DEHP as sole carbon source in minimal salt medium. However, reduction in their growth was observed at 700 ppm both DEP and DEHP. Out of eleven isolates, ten isolates belonged to class γ Proteobacteria, matched with sequences of Pseudomonas and Enterobacter. One isolate Achromobacter belonged to β- Proteobacteria. DEP degradation by Achromobacter xylosoxidans strain DEPA3 is reported for the first time in the present study and these might represent new DEP-degrading taxa. HPLC studies revealed decrease in the residual DEP and DEHP and formation of intermediates such as Phthalic acid by selected isolates. The three isolates viz Pseudomonas sp. DEHPA2, Pseudomonas sp. DEHPB2 and Pseudomonas sp. DEHPC2 were inoculated individually and also as consortium in MS broth containing 300 mg L-1 DEHP as sole carbon source. The most efficient degradation was observed when the three bacteria were inoculated as consortium. The DEHP percentage degradation was observed 79.8 - 87.8% after 10 days, 87.1- 91.3% after 20 days and 88.7 to 96.6% after 30 days of incubation in MS broth. Also, study in soil microcosm and the variation in percentage DEHP degradation among the bacterial isolates from 72.2 to 88.5% from 10 days to 30 days of incubation but a good DEHP percentage degradation was 116 observed with consortium of three bacteria. Three bacterial isolates namely viz. Achromobacter xylosoxidans strain DEPA3, Pseudomonas plecoglossicida strain DEPB3 and Enterobacter cloacae strain DEPC1 were selected for the degradation of DEP in MS broth and soil microcosm in different time interval by individuals and consortium of three bacteria. In MS broth (84.91 - 96.14%) observed more DEP degradation than soil microcosm (81.16-92.39%). The potential isolates obtained in the present study can be used for developing consortium which can be tested further at larger scale to strengthen the findings of the study. | en_US |
| dc.identifier.uri | http://krishikosh.egranth.ac.in/handle/1/5810136613 | |
| dc.language.iso | en_US | en_US |
| dc.publisher | DIVISION OF MICROBIOLOGY ICAR- INDIAN AGRICULTURAL RESEARCH INSTITUTE, NEW DELHI | en_US |
| dc.sub | Microbiology | en_US |
| dc.subject | null | en_US |
| dc.theme | Biodegradation of phthalate esters using efficient microorganisms | en_US |
| dc.these.type | Ph.D | en_US |
| dc.title | Biodegradation of phthalate esters using efficient microorganisms | en_US |
| dc.type | Thesis | en_US |