Faculty Publications
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Item Biological treatment of toxic petroleum spent caustic in fluidized bed bioreactor using immobilized cells of thiobacillus RAI01(2008) Potumarthi, R.; Mugeraya, G.; Jetty, A.In the present studies, newly isolated Thiobacillus sp was used for the treatment of synthetic spent sulfide caustic in a laboratory-scale fluidized bed bioreactor. The sulfide oxidation was tested using Ca-alginate immobilized Thiobacillus sp. Initially, response surface methodology was applied for the optimization of four parameters to check the sulfide oxidation efficiency in batch mode. Further, reactor was operated in continuous mode for 51 days at different sulfide loading rates and retention times to test the sulfide oxidation and sulfate and thiosulfate formation. Sulfide conversions in the range of 90-98% were obtained at almost all sulfide loading rates and hydraulic retention times. However, increased loading rates resulted in lower sulfide oxidation capacity. All the experiments were conducted at constant pH of around 6 and temperature of 30?±?5 °C. © 2008 Humana Press.Item Characterization and proinflammatory response of airborne biological particles from wastewater treatment plants(2011) Gangamma, S.; Patil, R.S.; Mukherji, S.Wastewater contains a variety of microorganisms, and unit operations in the plants could release these biological components into the air environment. These airborne biological particles could have adverse health effects on plant workers and the downwind population. This study provides a first report on the concentration and characterization of the airborne biological particles in six wastewater treatment plants in Mumbai, India. The study indicates that 49% and 27% of the samples exceed, respectively, the exposure limit for airborne endotoxin and bacteria in occupational settings. Endotoxin was identified as the single most important component of the particulate matter responsible for induction of proinflammatory indicator (tumor necrosis factor-?) in in vitro assay. Identification of several clinically important bacterial species in the samples suggests that the workers at the treatment plant are exposed to opportunistic and infectious bacteria. Principal component analysis was used to identify the groups among the bacterial species which serves as the signature for transport study. Analysis also shows that the component related to spore-forming bacteria is present in all samples. © 2011 American Chemical Society.Item Production of propyl gallate in nonaqueous medium using cell-associated tannase of Bacillus massiliensis: Effect of various parameters and statistical optimization(2013) Aithal, M.; Belur, P.D.Enzymatic synthesis of propyl gallate in an organic solvent was studied using cell-associated tannase (E.C. 3.1.1.20) of Bacillus massiliensis. Lyophilized biomass showing tannase activity was used as a biocatalyst. The influence of buffer pH and strength, water activity, temperature, biocatalyst loading, gallic acid concentration, and 1-propanol concentration was studied by the one-factor-at-a-time method. Subsequently, response surface methodology was applied based on a central composite design to determine the effects of three independent variables (biocatalyst loading, gallic acid concentration, and 1-propanol concentration) and their mutual interactions. A total of 20 experiments were conducted, and a statistical model was developed, which predicted the maximum propyl gallate yield of 20.28 ?g/mL in the reaction mixture comprising 40.4 mg biocatalyst, 0.4 mM gallic acid, and 6.52 % (v/v) 1-propanol in 9.5 mL benzene at 30°C. The subsequent verification experiments established the validity of the model. Under optimal conditions, 25% conversion of gallic acid to propyl gallate was achieved on a molar basis. The absence of the need for enzyme purification and subsequent immobilization steps and good conversion efficiency makes this enzyme system an interesting one. Reports on the applications of bacterial whole cell systems for synthetic reactions in organic solvents are scarce, and perhaps this is the first report on bacterial cell-associated tannase-mediated esterification in a nonaqueous medium. © 2013 International Union of Biochemistry and Molecular Biology, Inc.Item Enhancing gallic acid content in green tea extract by using novel cell-associated tannase of Bacillus massiliensis(2013) Palabhanvi, B.; Belur, P.D.Gallic acid content in green tea extract was enhanced by using a novel cell-associated tannase of Bacillus massiliensis. Biomass that contains tannase was used for this study. The activity of the cell-associated tannase was stable during 1 week of storage in the refrigerator. Response surface methodology was applied based on central composite design to determine the effects of three independent variables (pH, temperature and incubation time) and their mutual interactions. A total of 16 experiments were conducted; and a statistical model was developed, which predicted 475.74mg/L gallic acid production at pH6.2, 36C and incubation period of 16.71h. The subsequent verification experiments confirmed the validity of the model. Under optimal conditions, 84.7% of the total hydrolyzable tannins were converted to gallic acid and glucose. This naturally immobilized tannase was stable enough to be used for up to 12 runs. Practical Applications: The current study shows that naturally immobilized tannase of Bacillus massiliensis can be used instead of artificially immobilized tannase. Such naturally immobilized tannase has many advantages as it avoids expensive and laborious isolation, purification and immobilization. Ease of separation of cell-associated enzyme from the reaction mixture and absence of any detectable extracellular tannase activity after enzymatic treatment are some of the encouraging facts. Stability during storage up to 7 days, 85% tannic acid hydrolyzing efficiency, activity at pH3.5-8.0 and operational stability for 12 runs are some of the interesting features of this naturally immobilized enzyme. However, its application for tea treatment will be limited until Bacillus massiliensis gets "Generally Recognized As Safe" status. It can be employed, however, for production of gallic acid from agro residues and production of propyl gallate. © 2012 Wiley Periodicals, Inc.Item Cadmium (II) and nickel (II) biosorption by Bacillus laterosporus (MTCC 1628)(Taiwan Institute of Chemical Engineers, 2014) Kulkarni, R.; Shetty K, V.; Srinikethan, G.Biosorption of heavy metals is a promising technology that involves removal of toxic metals from industrial waste streams and natural waters. The study describes the sorption of cadmium (II) [Cd (II)] and nickel (II) [Ni (II)] by dead biomass of Bacillus laterosporus, MTCC 1628. The biosorption conditions for the removal of Cd (II) and Ni (II) were examined by studying the effect of pH, contact time, biosorbent dosage and initial metal ion concentration. Shake flask studies yielded adsorption equilibrium in almost 120. min, for both the metals. It was found from Langmuir model that the maximum adsorption capacity for Cd (II) and Ni (II) ions was 85.47. mg/g and 44.44. mg/g respectively. Kinetic evaluation of the experimental data showed that the biosorption process followed pseudo-second order kinetics. Thermodynamic analysis showed that biosorption is an endothermic process with ?. H° of 5.45. kJ/mol for Cd (II) biosorption and 24.33. kJ/mol for Ni (II) biosorption. The surface characteristics of B. laterosporus biomass before and after metal biosorption were analyzed by using scanning electron microscope (SEM) with energy dispersive X-ray spectroscopy (EDAX) to study the changes in surface morphology and elemental constitution of the adsorbent. B. laterosporus exhibited a higher and better potential biosorbent for the removal of Cd (II) as compared to Ni (II) from aqueous solution. © 2013 Taiwan Institute of Chemical Engineers.Item Biosynthesis of copper nanoparticles using copper-resistant Bacillus cereus, a soil isolate(Elsevier Ltd, 2016) Tiwari, M.; Jain, P.; Raghu Chandrashekar, R.; Narayanan, K.; Bhat, K.U.; Udupa, N.; Rao, J.V.Microorganisms are useful systems for the production of biocompatible metal nanoparticles. Copper, an essential element of life, has good therapeutic potential. However, copper lacks suitable form for effective in vivo delivery, which has diminished its applicability. In this study, we produced biosynthesized copper nanoparticles (BCuNps) using a copper-resistant bacterial isolate from copper mine. The organism was able to tolerate >10 mM of copper and when analysed by 16S rRNA technique, showed 100% similarity with Bacillus cereus. BCuNps, produced by this microorganism, in cell-free filtrate, were characterized for surface plasmon resonance (SPR), particle's characteristics, spectroscopic properties and morphology. SPR peaks for BCuNps were recorded between 570–620 and 350–370 nm. BCuNps characteristics, namely particle size distribution, polydispersity index and zeta potential were found to be 11–33 nm, 0.433 and (?) 19.6 mV, respectively. Scanning electron microscope (SEM), transmission electron microscope (TEM) and atomic force microscope (AFM) analyses confirmed the uniform morphology; X-ray diffraction (XRD) spectrum revealed the crystalline nature; and Fourier transform infrared (FTIR) spectrum disclosed the presence of protein with BCuNps. A comparative evaluation of BCuNps with copper sulphate to determine their antimicrobial and cell toxicity levels was undertaken. BCuNps showed better antimicrobial effect and found to be safer against normal cell lines, such as HaCat, Vero and hFOB, than the copper sulphate control. © 2016 Elsevier LtdItem The combined effects of carbon/nitrogen ratio, suspended biomass, hydraulic retention time and dissolved oxygen on nutrient removal in a laboratory-scale anaerobic–anoxic–oxic activated sludge biofilm reactor(IWA Publishing, 2018) Manu, D.S.; Thalla, A.K.The current trend in sustainable development deals mainly with environmental management. There is a need for economically affordable, advanced treatment methods for the proper treatment and management of domestic wastewater containing excess nutrients (such as nitrogen and phosphorus) which can cause eutrophication. The reduction of the excess nutrient content of wastewater by appropriate technology is of much concern to the environmentalist. In the current study, a novel integrated anaerobic–anoxic–oxic activated sludge biofilm (A2O-AS-biofilm) reactor was designed and operated to improve the biological nutrient removal by varying reactor operating conditions such as carbon to nitrogen (C/N) ratio, suspended biomass, hydraulic retention time (HRT) and dissolved oxygen (DO). Based on various trials, it was seen that the A2O-AS-biofilm reactor achieved good removal efficiencies with regard to chemical oxygen demand (95.5%), total phosphorus (93.1%), ammonia nitrogen concentration (NH4þ-N) (98%) and total nitrogen (80%) when the reactor was maintained at C/N ratio of 4, suspended biomass of 3 to 3.5 g/L, HRT of 10 h, and DO of 1.5 to 2.5 mg/L. Scanning electron microscopy (SEM) of suspended and attached biofilm showed a dense structure of coccus and bacillus bacteria with the diameter ranging from 0.3 to 1.2 ?m. The Fourier transform infrared (FTIR) spectroscopy results indicated phosphorylated macromolecules and carbohydrates mix or bind with extracellular proteins in exopolysaccharides. © IWA Publishing 2018.Item Degradation of Triclosan from Domestic Wastewater by Biosurfactant Produced from Bacillus licheniformis(Humana Press Inc. humana@humanapr.com, 2019) Jayalatha, N.A.; Devatha, C.P.The use of triclosan (TCS), an antimicrobial agent in consumer product, results in adverse effects on the environment due to its wide usage all over the world. The present study focused on TCS detection and attempted for degradation by biosurfactant produced by Bacillus licheniformis from domestic wastewater in Surathkal region, Karnataka, India. The experimental investigation includes biosurfactant production using crude sunflower oil and detection and degradation of TCS from wastewater by High-Performance Liquid Chromatography (HPLC). Results exhibited that maximum biosurfactant yield (7.8 g/L) was achieved using 1 g/L of glycerol as carbon and 5.5 g/L of ammonium bicarbonate as a nitrogen source. Detection of TCS from domestic wastewater (0.36 mg/L) and degradation was carried out by HPLC. The result discloses that 47.2% and 100% removal of TCS was achieved in 2 h and 16 h for 1:1(v/v) ratio of wastewater and biosurfactant. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.Item Novel application of maghemite nanoparticles coated bacteria for the removal of cadmium from aqueous solution(Academic Press, 2020) Devatha, C.P.; S, S.Heavy metals are classified as persistent pollutants owing to their nature of bioaccumulation and affect human life and environment, even in minor concentrations. Divalent Cadmium (Cd2+) is one of the heavy metal pollutants that are highly toxic. The present study investigates the novel application of maghemite nanoparticles coated Bacillus subtilis for the removal of Cd2+ ions from its aqueous solution by batch adsorption studies. Surface characterization of the biosorbent done by Scanning Electron Microscope (SEM) and the presence of maghemite nanoparticle coat was confirmed. Parameters like pH, initial metal ion concentration, contact time, and temperature that affect the biosorption of cadmium ions are analyzed, and the equilibrium adsorption capacity expressed as a function of each of the parameters. The mechanism of biosorption was studied by plotting adsorption isotherms, and it follows pseudo-second-order kinetics. Thermodynamic studies showed the process to be spontaneous and endothermic. At optimum conditions of pH 4, 30 °C, 120 rpm, maximum removal percentage of 83.5%, which accounts for an equilibrium adsorption capacity of 32.6 mg/g of biosorbent. There was a recovery of 76.4% of the biosorbent after adsorption studies. Based on the adsorptive capacity and good recovery of the biosorbent, maghemite coated Bacillus subtilis proves to be an efficient adsorbent for the removal of Cd2+ ions from its aqueous solution. © 2019 Elsevier LtdItem Engineering a recombinant chitinase from the marine bacterium Bacillus aryabhattai with targeted activity on insoluble crystalline chitin for chitin oligomer production(Elsevier B.V., 2024) Subramani, A.K.; Ramachandra, R.; Thote, S.; Govindaraj, V.; Vanzara, P.; Raval, R.; Raval, K.Chitin, an abundant polysaccharide in India, is primary by-product of the seafood industry. Efficiently converting chitin into valuable products is crucial. Chitinase, transforms chitin into chitin oligomers, holds significant industrial potential. However, the crystalline and insoluble nature of chitin makes the conversion process challenging. In this study, a recombinant chitinase from marine bacteria Bacillus aryabhattai was developed. This enzyme exhibits activity against insoluble chitin substrates, chitin powder and flakes. The chitinase gene was cloned into the pET 23a plasmid and transformed into E. coli Rosetta pLysS. IPTG induction was employed to express chitinase, and purification using Ni-NTA affinity chromatography. Optimal chitinase activity against colloidal chitin was observed in Tris buffer at pH 8, temperature 55°C, with the presence of 400 mM sodium chloride. Enzyme kinetics studies revealed a Vmax of 2000 μmole min−1 and a Km of 4.6 mg mL−1. The highest chitinase activity against insoluble chitin powder and flakes reached 875 U mg−1 and 625 U mg−1, respectively. The chitinase demonstrated inhibition of Candida albicans, Fusarium solani, and Penicillium chrysogenum growth. Thin Layer Chromatography (TLC) and LC-MS analysis confirmed the production of chitin oligomers, chitin trimer, tetramer, pentamer, and hexamer, from chitin powder and flakes using recombinant chitinase. © 2024 Elsevier B.V.