Assessment of microbial diversity and biological quality of riverine and effluent water for bioremediation potential

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dc.contributor.advisorKatyal, Priya
dc.contributor.authorHarpreet Kaur
dc.date.accessioned2023-07-12T08:33:50Z
dc.date.available2023-07-12T08:33:50Z
dc.date.issued2022
dc.description.abstractThe increase in the modern industrial era to satisfy the requirements of the growing population in Punjabresulted in the release of exceedingly hazardous chemicals into the water resources causing an imbalance in the environment and human health as well. Metal remediation through conventional technologies is much moreexpensive and leads to the production of secondary wastes and has less treatment efficiency at low heavy metalconcentrations. In this regard, bioremediation by using metal-resistant microbes is considered an eco-friendly approach to clean up environmental pollution. A systematic study was carried out to assess the heavy metal content (As, Cd, Ni, Pb and Ni), physicochemical and biological parameters viz. pH, electrical conductivity (EC), biological oxygen demand (BOD), chemical oxygen demand (COD), heterotrophic plate count (HPC) and total coliforms (TC) of riverine (River Beas) and effluent (Buddha Nallah) water of Punjab with seasonal variation (winter, pre-monsoon, monsoon and post-monsoon) during 2020-21. The mean values of BOD, COD, HPC and TC were found significantly higher during the monsoon season while heavy metal content was found higher during the post-monsoon season in both water resources. Overall, a highly significant correlation between physicochemical, biological and heavy metal parameters was observed in effluent water as compared to the riverine water. The high incidences of Escherichia coli (100%), Klebsiella spp. (100%), Vibrio cholera (100%), Staphylococcus spp. (100%), Salmonella spp. (71.4%), Listeria spp. (71.4%), Campylobacter spp. (71.4%), Aeromonas spp. (85.7%) and Shigella spp. (57.1%) was observed in the samples of effluent water as compared to riverine water samples. A total of 68 morphologically distinct bacterial isolates (BHR1 to BHR68) were procured from riverine (25) and effluent water (43) and were tested for metal resistance against six heavy metals i.e. As, Cd, Cr, Hg, Ni and Pb with increasing the metal concentration in media (10-100 ppm). Out of 68 isolates, 25 exhibited a high metal tolerance against these heavy metals. These heavy metal resistant bacterial isolates tested for antibiotic susceptibility assay showed MAR index with a range of 0.25- 0.91. The co-existence of heavy metal and antibiotic resistance was observed most commonly in Cr, Pb and Ni resistant bacterial isolates. These 25 isolates were tested for virulence profile (biofilm formation, congo-red binding, blood haemolysis, esculin hydrolysis, pyrazinamidase, DNase, lipase and protease tests) and only six non-pathogenic isolates i.e. BHR1, BHR2, BHR4, BHR5, BHR6 and BHR8 exhibited high metal tolerance and molecularly these isolates were identified as Bacillus thuringiensis, Bacillus cereus, Enterobacter cloacae, Bacillus pumilus, Bacillus altitudinis and Klebsiella pneumonia, respectively. The polymerase chain reaction (PCR) technique was used to check whether the heavy-metal resistance capacity of the isolates is linked to specific metal transporter genes (chrA, chrB, pbrA, nccA, czcA, czcB and czcD). Based on minimum inhibitory concentration (MIC) and bacterial growth patterns, only two bacterial isolates i.e. BHR1 and BHR5 were found to be highly effective in tolerating a high concentration of heavy metal and were selected as potent candidates for bioremediation. BHR1 isolate showed the higher metal uptake of metals in effluent sample supplemented with minimal media with modified pH after 96 h incubation. Cr (VI) reduction capacity was determined by the diphenylcarbazide (DPC) method and was found maximum with BHR1 with higher chromate reductase activity in cell wall fraction (0.412 U/ml) which was further confirmed through SEM-EDS analysis. Moreover, Cr (VI) resistant bacterial isolates were found to show plant growth promoting (PGP) traits and were used in pot culture experiment using fodder variety of maize (J-1007). The effect of these isolates (individual and as consortia) on germination, growth and phytoextraction suggest the possible application of the isolates in phytoremediation studies.en_US
dc.identifier.citationHarpreet Kaur (2022). Assessment of microbial diversity and biological quality of riverine and effluent water for bioremediation potential (Unpublished Ph.D. Dissertation). Punjab Agricultural University, Ludhiana, Punjab, India.en_US
dc.identifier.urihttps://krishikosh.egranth.ac.in/handle/1/5810198162
dc.keywordsAntibiotic susceptibility, Bioremediation, Cr (VI) reduction, Effluent water, Heavy metals, Metal resistant genes, Riverine wateren_US
dc.language.isoEnglishen_US
dc.pages169en_US
dc.publisherPunjab Agricultural University, Ludhianaen_US
dc.research.problemAssessment of microbial diversity and biological quality of riverine and effluent water for bioremediation potentialen_US
dc.subMicrobiologyen_US
dc.themeAssessment of microbial diversity and biological quality of riverine and effluent water for bioremediation potentialen_US
dc.these.typePh.Den_US
dc.titleAssessment of microbial diversity and biological quality of riverine and effluent water for bioremediation potentialen_US
dc.typeThesisen_US
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