Department Of Environmental Science And Technology
Permanent URI for this communityhttps://kr.cup.edu.in/handle/32116/84
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Item Screening of quorum quenching activity of the bacteria isolated from dairy industry waste activated sludge(Center for Environmental and Energy Research and Studies, 2018) Kaur, J.; Yogalakshmi, K.N.Intercellular bacterial communication process via exchange of signalling molecules acyl homoserine lactone results in various group activities like bioluminescence, antibiotic production, biofilm formation, sporulation, and virulence. The signalling molecules are targeted, and the communication is interrupted by a group of bacteria termed quorum quenching bacteria. The present study aims to isolate the quorum quenching bacteria from the waste activated sludge collected from the dairy industry effluent treatment plant and explore for its quorum quenching potential. The bacteria were cultured in the KG medium containing n-hexanoyl homoserine lactone as a sole source of carbon and nitrogen. The isolates were identified by the 16S ribosomal deoxyribonucleic acid analysis and subsequently were evaluated for its quorum quenching activity through Chromobacterium violaceum CV026 biosensor assay. The n-hexanoyl homoserine lactone degradation was quantified by GC–MS analysis. The 16S ribosomal deoxyribonucleic acid analysis revealed the isolated bacteria as Klebsiella pneumoniae (JYQ1 and JYQ5), Acinetobacter baumannii JYQ2, Pseudomonas nitroreducens JYQ3, and Pseudomonas JYQ4. The biosensor strain assay and GC–MS analysis indicated that all the isolates possessed an inherent ability to degrade N-hexanoyl homoserine lactone. The strain Pseudomonas JYQ4 exhibited the highest quorum quenching activity of 84 ± 3.3% within 6 h of incubation. The strain A. baumannii JYQ2 acted both as quorum sensing and as quorum quenching bacteria as evidenced by the decrease in quorum quenching from 79 ± 3.1 to 76.8 ± 2.5%.Item Effect of enzyme secreting bacterial pretreatment on enhancement of aerobic digestion potential of waste activated sludge interceded through EDTA(Elsevier Ltd, 2013) Kavitha, S.; Adish Kumar, S.; Yogalakshmi, K.N.; Kaliappan, S.; Rajesh Banu, J.In this study, the effect of Ethylene diamine tetra acetic acid (EDTA) on Extracellular polymeric substance (EPS) removal tailed with bacterial enzymatic pretreatment on aerobic digestion of activated sludge was studied. In order to enhance the accessibility of sludge to the enzyme secreting bacteria; the extracellular polymeric substances were removed using EDTA. EDTA efficiently removed the EPS with limited cell lysis and enhanced the sludge enzyme activity at its lower concentration of 0.2. g/g SS. The sludge was then subjected to bacterial pretreatment to enhance the aerobic digestion. In aerobic digestion the best results in terms of Suspended solids (SS) reduction (48.5%) and COD (Chemical oxygen demand) solubilization (47.3%) was obtained in experimental reactor than in control. These results imply that aerobic digestion can be enhanced efficiently through bacterial pretreatment of EPS removed sludge. ? 2013 Elsevier Ltd.Item Optimization of Copper (II) Removal by Response Surface Methodology Using Root Nodule Endophytic Bacteria Isolated from Vigna unguiculata(Springer International Publishing, 2016) Manohari, R.; Yogalakshmi, K.N.The present study was conducted to investigate copper tolerance and bioremediation potential in endophytic bacteria isolated from Vigna unguiculata root nodules. Total ten endophytes were isolated on yeast mannitol agar and enriched in copper (II) sulfate (CuSO4) up to 500?mg/L. Four endophytes belonging to genera Bacillus and Arthrobacter showed copper tolerance. The isolates were identified as Arthrobacter tumbae MYR1, Bacillus safensis MYR2, Bacillus pumilus MYR3 and Bacillus sp. MYR4 using 16S ribosomal RNA (rRNA) analysis. Response surface methodology was used for copper (II) removal optimization. The model was significant with R2, P and F value of 0.9780, <0.0001, and 34.54, respectively. Results showed that highest copper (II) bioremoval of 82.8?% was obtained at pH 5.0, temperature 32.5??C, and 600?mg/L copper concentration after 168?h of incubation. The isolates were tested for plant growth promotion and all the strains produced indole acetic acid (IAA) and showed 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity. The study concludes that endophytic bacteria possessed greater potential for copper tolerance and bioremediation. ? 2016, Springer International Publishing Switzerland.Item Treatment of seafood processing wastewater using upflow microbial fuel cell for power generation and identification of bacterial community in anodic biofilm(Academic Press, 2016) Jayashree, C.; Tamilarasan, K.; Rajkumar, M.; Arulazhagan, P.; Yogalakshmi, K.N.; Srikanth, M.; Banu, J.R.Tubular upflow microbial fuel cell (MFC) utilizing sea food processing wastewater was evaluated for wastewater treatment efficiency and power generation. At an organic loading rate (OLR) of 0.6 g d-1, the MFC accomplished total and soluble chemical oxygen demand (COD) removal of 83 and 95%, respectively. A maximum power density of 105 mW m-2 (2.21 W m-3) was achieved at an OLR of 2.57 g d-1. The predominant bacterial communities of anode biofilm were identified as RB1A (LC035455), RB1B (LC035456), RB1C (LC035457) and RB1E (LC035458). All the four strains belonged to genera Stenotrophomonas. The results of the study reaffirms that the seafood processing wastewater can be treated in an upflow MFC for simultaneous power generation and wastewater treatment. ? 2016 Elsevier Ltd.Item Effect of organic loading rate on electricity generating potential of upflow anaerobic microbial fuel cell treating surgical cotton industry wastewater(Elsevier Ltd, 2017) Tamilarasan, K.; Banu, J.R.; Jayashree, C.; Yogalakshmi, K.N.; Gokulakrishnan, K.In this study, the performance of continuous fed upflow anaerobic microbial fuel cell operated with surgical cotton industry wastewater was investigated at different Organic Loading Rate (OLR). The potency of power generation, COD and TSS removal efficiency was determined. The highest TCOD and SCOD removal of 78.8% and 69%, respectively was accomplished at an optimum OLR of 1.9 gCOD/L d. A 62% TSS removal efficiency was obtained, with an initial TSS concentration of wastewater as 970 ? 70 mg/L. The maximum power density 116.03 mW/m2 (2.2 W/m3) and corresponding coulombic efficiency of 17.8% was achieved at the OLR of 1.9 gCOD/L/d while treating surgical cotton industry waste water. ? 2017 Elsevier Ltd.Item Laccase immobilized magnetic iron nanoparticles: Fabrication and its performance evaluation in chlorpyrifos degradation(Elsevier Ltd, 2017) Das, A.; Singh, J.; Yogalakshmi, K.N.Chlorpyrifos degradation was studied using laccase immobilized on magnetic iron nanoparticles (CENPs). The magnetic iron nanoparticles (MNPs) prepared by co-precipitation method were characterized using Transmission electron microscopy (TEM), Scanning electron microscopy- Energy dispersive spectroscopy (SEM-EDS) and Thermogravimetric analysis (TGA). The size of the nanoparticles ranged between 10 and 15 nm. The MNPs were coated with chitosan, surface modified with carbodiimide (EDAC) immobilized with laccase enzymes. The chlorpyrifos degradation studies were performed in batch studies under constant shaking for a period of 12 h. Results of the study showed that laccase immobilized on magnetic iron nanoparticles were effective in degrading more than 99% chlorpyrifos in 12 h at pH 7 and 60 ?C. In the overall degradation percentage, MNPs contributed to 32.3% of chlorpyrifos removal while ENPs resulted in 58.8% chlorpyrifos degradation. Immobilization of enzyme decreased the overall activity of the free enzyme. The CENPs showed 95% activity after five repeated washing and hence possess good reusability potential. ? 2017 Elsevier Ltd