BITS Faculty Publications
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Item Solubilization and degradation of polychlorinated biphenyls (PCBs) by naturally occurring facultative anaerobic bacteria(Elsevier, 2019-02) Goonetilleke, AshanthaA combination of solubilization and degradation is essential for the bioremediation of environments contaminated with complex polychlorinated biphenyls (PCB) mixtures. However, the application of facultative anaerobic microorganisms that can both solubilize and breakdown hydrophobic PCBs in aqueous media under both anaerobic and aerobic conditions, has not been reported widely. In this comprehensive study, four bacteria discovered from soil and sediments and identified as Achromobacter sp. NP03, Ochrobactrum sp. NP04, Lysinibacillus sp. NP05 and Pseudomonas sp. NP06, were investigated for their PCB degradation efficiencies. Aroclor 1260 (50 mg/L), a commercial and highly chlorinated PCB mixture was exposed to the different bacterial strains under aerobic, anaerobic and two stage anaerobic–aerobic conditions. The results confirmed that all four facultative anaerobic microorganisms were capable of degrading PCBs under both anaerobic and aerobic conditions. The highest chlorine removal (9.16 ± 0.8 mg/L), PCB solubility (14.7 ± 0.93 mg/L) and growth rates as OD600 (2.63 ± 0.22) were obtained for Lysinibacillus sp. NP05 under two stage anaerobic-aerobic conditions. The presence of biosurfactants in the culture medium suggested their role in solubility of PCBs. Overall, the positive results obtained suggest that high PCB hydrolysis can be achieved using suitable facultative anaerobic microorganisms under two stage anaerobic-aerobic conditions. Such facultative microbial strains capable of solubilization as well as degradation of PCBs under both anaerobic and aerobic conditions provide an efficient and effective alternative to commonly used bioaugmentation methods utilizing specific obligate aerobic and anaerobic microorganisms, separately.Item Characterization and oil recovery application of biosurfactant produced during bioremediation of waste engine oil by strain Pseudomonas aeruginosa gi|KP 16392| isolated from Sambhar salt lake(Taylor & Francis, 2021-05-05) Jain, Amit; Gupta, SureshHalophilic bacterium, Pseudomonas aeruginosa gi|KP 16392| isolated from Sambhar salt lake in the southwest region of the city of Jaipur, India was tested for the first time for potential application in waste engine oil bioremediation and simultaneous biosurfactant production. In this study, the batch experiments were performed on culture grown in mineral salt medium supplemented with 5% (v/v) waste engine oil as the sole carbon source incubated for a week at pH 7.0, maintaining 35 °C and 150 rpm. The bacterial growth was monitored by the optical density and dry biomass content measurements. The biosurfactant production was affirmed with the reduction in surface tension of the culture medium from 72 ± 0.36 to 29.61 ± 0.14 mN/m. Of the total waste engine oil fed, 74.35 ± 0.037% was consumed and biodegraded to secondary metabolites. The biosurfactant yield was found to be approximately 1.02 g/L. The functional groups in the product, identified with the Fourier transform infrared spectroscopy confirms to be rhamnolipid and characterized using microbial adhesion to hydrocarbon (math) test and methyl assay. The emulsification activity of the produced biosurfactant was assessed for various hydrophobic substrates and was found to be comparable to the chemical surfactant (sodium dodecyl sulfate). The biosynthetic pathway (de novo synthesis) used by microbial strain to form rhamnolipid is schematically represented. The performance of the purified biosurfactant in oil recovery application was tested using a simulated waste engine oil contaminated soil and it showed excellent surface activity.Item Estimation of Kinetic Parameters for Bioremediation of Cr(VI) from Wastewater Using Pseudomonas taiwanensis, an Isolated Strain from Enriched Mixed Culture(Taylor & Francis, 2014-08-08) Gupta, Suresh; Raghuvanshi, Smita; Majumder, SubhajitAn aerobic mixed culture collected in the form of activated sludge was enriched for Cr(VI) reduction. An indigenous microorganism was isolated from the enriched aerobic mixed culture and identified as Pseudomonas taiwanensis. Bioremediation studies were carried out for treating Cr(VI)-contaminated wastewater using the indigenous microorganism. The kinetic studies were carried out for initial Cr(VI) concentrations ranging from 20 to 200 mg L−1. The maximum consumption of Cr(VI) obtained was 108.3 mg L−1 for an initial Cr(VI) concentration of 150 mg L−1 at a solution pH of 7.0. The effect of nutrient dosage and pH were studied to get their optimum values. The same isolated bacterial strain was also used to treat Cr(VI)-contaminated industrial wastewater collected from a local plating industry. Various growth kinetic models, such as Monod, Powell, Haldane, Luong, and Edward models, were fitted with the obtained experimental data. The obtained results for different growth kinetic models indicate that the growth kinetics of Pseudomonas taiwanensis for bioremediation of Cr(VI) can be better understood by the Luong model (R2 = .913). The rate kinetic analysis was performed using zero-order and three-half-order kinetic models. The three-half-order kinetic model was found to be suitable for the present bioremediation study.Item A comprehensive study on the behavior of a novel bacterial strain Acinetobacter guillouiae for bioremediation of divalent copper(Springer, 2015-05-28) Gupta, Suresh; Raghuvanshi, Smita; Majumder, SubhajitBiological methods have been successfully used to mitigate heavy metal pollution problem in wastewater. The present study was aimed towards isolation of a novel indigenous bacterial strain, Acinetobacter guillouiae from activated sludge and its subsequent application in remediation of copper (Cu2+) from aqueous solution. Kinetic study of bioremediation was performed for initial Cu2+ concentrations ranging from 40 to 150 mg L−1. Optimum values of nutrient dosage, pH, macronutrients [Nitrogen (N)–Phosphorus (P)–Potassium (K)] dosage, aerobic and facultative anaerobic conditions, temperature, and inoculum volume were determined by conducting separate batch bioremediation studies at 80 mg L−1 initial concentration of Cu2+. Kinetic study showed that A. guillouiae removed 98.7 % Cu2+ for 80 mg L−1 initial concentration of Cu2+ after 16 h at an optimum solution pH of 7.0. Results also revealed that A. guillouiae showed maximum growth at double the standard composition of N, P and standard composition of K in nutrient dosage. Experimental data obtained in present study were utilized to validate different growth kinetic models such as Monod, Powell, Haldane, Luong, and Edwards. Growth kinetics of A. guillouiae was better understood by Luong model (R 2 = 0.97). Higher values of coefficient of determination (R 2 = 0.97–0.99) confirmed the suitability of the three-half-order kinetic model for representing the Cu2+ bioremediation. A. guillouiae showed a robust removal mechanism for the bioremediation of Cu2+.Item Bioremediation of cadmium by metal resistant strain of Cyanobacteria(Scientific Publisher, 2002) Verma, Sanjay Kumar