K. Ramani

Microbial induced lipoprotein biosurfactant from slaughterhouse lipid waste and its application to the removal of metal ions from aqueous solution

This study aims at demonstrating the production of lipoprotein biosurfactant from Pseudomonas gessardii using goat tallow, a slaughterhouse lipid waste, as the substrate and its application to the removal of metal ions from aqueous solution. The maximum bio-transformation of goat tallow into biosurfactant occurred at 48 h. The mass of the lipoprotein biosurfactant produced was 2.03 g/g of goat tallow. The biosurfactant was clearly characterized by surface tension, critical micelle concentration, emulsification index and molecular weight. The amino acid and fatty acid moieties of the biosurfactant were determined using High performance liquid chromatography (HPLC) and Gas chromatography (GC). The thermal behavior studies were evaluated using Thermo gravimetric (TG) and Differential scanning calorimetry (DSC) analysis. The lipoprotein biosurfactant was loaded onto the mesoporous activated carbon (MAC) for the sequestering of metal ions from the aqueous solution. The biosurfactant exhibited a removal efficiency for metal ions from aqueous solution in the order Cr(3+)>Ca(2+)>Cu(2+)>Fe(2+). The morphological observations and functional groups of the lipoprotein biosurfactant and that of the lipoprotein biosurfactant bound metal ions were determined using scanning electron micrograph (SEM) images and Fourier transform infrared (FT-IR) spectroscopy, respectively. This is the first report on the production of lipoprotein biosurfactant by P. gessardii using goat tallow as the substrate to sequester the metal ions from the aqueous solution.

GC–MS Analysis of Bio-active Molecules Derived from Paracoccus pantotrophus FMR19 and the Antimicrobial Activity Against Bacterial Pathogens and MDROs

Abstract The present investigation is focused on the study of chemical composition of a bioactive compound derived from a rumen isolate Paracoccus pantotrophus FMR19 using GC–MS and to find out the antibacterial activity of the extracted crude bioactive compounds against multidrug resistant organisms (MDROs) and other clinical pathogens. GC–MS analysis revealed that P. pantotrophus FMR19 produced eight major compounds that have been reported to exhibit antimicrobial property. The main components identified from hexane fraction are long chain alkanes, fatty alcohols, fatty acid methyl ester and aromatic hydrocarbons. These molecules are not only active against clinical pathogens such as Salmonella sp. and Proteus sp. and also effective against MDROs such as Metallo β lactamase and Pan drug resistant bacterial strains and Methicillin resistant Staphylococcus aureus.

Biocatalytic approach on the treatment of edible oil refinery wastewater

The number of edible oil refineries has increased in the last few years, with a corresponding increase in oil production. As a result, edible oil-containing wastewater (EOCW) is being produced in huge quantities. Conventional technologies are inefficient at treating this wastewater due to the highly hydrophobic nature of the lipids. In the present study, we have used lipase immobilized nanoporous activated carbons and surface functionalized nanoporous activated carbons for the treatment of lipid-containing wastewater. The nanoporous activated carbon (NAC) was prepared from rice husks and the NAC was surface functionalized by the addition of ethylenediamine and glutaraldehyde with (FNAC2) and without (FNAC1) the addition of a reducing agent, sodium borohydride. The lipase obtained from marine Pseudomonas otitidis, using cooked waste sunflower oil (CWSO) as the substrate, was then immobilized onto the NAC and the functionalized nanoporous activated carbons (FNAC1 and FNAC2). The maximum immobilization capacities of NAC, FNAC1 and FNAC2 were 3640, 4788 and 4400 U g−1, respectively, at the optimum conditions. The carrier matrices in the free and lipase immobilized form were characterized using scanning electron microscopy, Fourier transform infrared spectrometry and X-ray diffraction. The thermal behavior of the free and immobilized lipases was studied using thermogravimetric analysis. Michaelis–Menten enzyme kinetics, adsorption isotherms and nonlinear kinetic models were evaluated for the immobilization of lipase. The lipase immobilized carrier matrices were employed in the treatment of EOCW under batch and continuous mode operations. At the end of the 50th cycle, FNAC1-L (89.78%) showed a higher operational stability than FNAC2-L (87.36%) and NAC-L (76.59%). The treatment of EOCW by immobilized lipases followed the pseudo second order rate kinetic model.

Microbial assisted industrially important multiple enzymes from fish processing waste: purification, characterization and application for the simultaneous hydrolysis of lipid and protein molecules

Fish processing waste (FPW) was evaluated as the substrate for the concomitant production of industrially important alkaline lipase and protease by Streptomyces thermolineatus for the hydrolysis of lipid and protein rich FPW. The FPW contributed to the effective growth of the organism and also aided the enzyme production. Media optimization was performed using response surface methodology for maximum enzyme production (lipase 402 U ml−1; protease 896 U ml−1). The enzymes were purified with ammonium sulphate precipitation, dialysis, and gel filtration chromatography and achieved a specific activity of lipase and protease of 903 and 2539 U mg−1 respectively, and purity of 8.6 and 10.8 fold respectively. The purified enzymes were stable over a wide range of temperatures (30–70 °C), pH (6.5–9.5), organic solvents and surfactants, with higher affinities for their substrates. Hydrolysis studies showed that the purified lipase and protease hydrolysed 76 and 86% of lipid and protein respectively. In conclusion, these enzymes have great potential for industrial applications especially treating waste containing multiple substrates.

Enhanced biodegradation of hydrocarbons in petroleum tank bottom oil sludge and characterization of biocatalysts and biosurfactants

Petroleum hydrocarbon removal from tank bottom oil sludge is a major issue due to its properties. Conventional physicochemical treatment techniques are less effective. Though the bioremediation is considered for the hydrocarbon removal from tank bottom oil sludge, the efficiency is low and time taking due to the low yield of biocatalysts and biosurfactants. The focal theme of the present investigation is to modify the process by introducing the intermittent inoculation for the enhanced biodegradation of hydrocarbons in the tank bottom oil sludge by maintaining a constant level of biocatalysts such as oxidoreductase, catalase, and lipase as well as biosurfactants. In addition, the heavy metal removal was also addressed. The microbial consortia comprising Shewanalla chilikensis, Bacillus firmus, and Halomonas hamiltonii was used for the biodegradation of oil sludge. One variable at a time approach was used for the optimum of culture conditions. The bacterial consortia degraded the oil sludge by producing biocatalysts such as lipase (80 U/ml), catalase (46 U/ml), oxidoreductase (68 U/ml) along with the production of lipoprotein biosurfactant (152 mg/g of oil sludge) constantly and achieved 96% reduction of total petroleum hydrocarbon. The crude enzymes were characterized by FT-IR and the biosurfactant was characterized by surface tension reduction, emulsification index, FT-IR, TLC, and SDS-PAGE. GC-MS and NMR also revealed that the hydrocarbons present in the oil sludge were effectively degraded by the microbial consortia. The ICP-OES result indicated that the microbial consortium is also effective in removing the heavy metals. Hence, bioremediation using the hydrocarbonoclastic microbial consortium can be considered as an environmentally friendly process for disposal of tank bottom oil sludge from petroleum oil refining industry.

A novel mariner-based transposon system for the enhanced removal of high strength ammoniacal nitrogen in pharmaceutical effluents

Industrial wastewater is a major polluting agent in the environment as huge amounts of untreated effluents are discharged from industries causing serious effects to biotic systems. The pharmaceutical industry effluent used in the present study contains a high concentration of ammoniacal nitrogen (NH3–N) about 500 mg L−1. In the present study, an efficient NH3–N removing strain was isolated, and enriched in the effluent with a high NH3–N concentration for its efficient removal. The strain which showed higher removal efficiency was identified as Proteus penneri by ribotyping. The wild type P. penneri exhibited low removal efficiency (64%) in 24 hours even after the conventional enrichment method. Hence, the strain was mutated to improve its degradation efficiency using a modified mariner based transposon system. It was constructed by replacing the Kanr gene with Gmr gene to develop pSC189::miniTn(Gm), since the isolated strain was resistant to kanamycin. Two mutant strains T55 and T132 were shown to have enhanced NH3–N removal efficiency by 84% and 81% respectively, in 24 hours. The kinetic rate constants such as pseudo first and second order kinetics were evaluated for the degradation of NH3–N by wild type P. penneri and transposon mutants; both of them followed second order rate kinetics. The NH3–N removal was confirmed by ion chromatography (IC) and Fourier Transform-Infrared Spectroscopy (FT-IR). To date, there is no report on the strain improvement using transposon mutagenesis for the treatment of NH3–N.