ABSTRACT
The marine strain Pseudomonas otitidis was isolated to hydrolyze the cooked sunflower oil (CSO) followed by the production of lipase. The optimum culture conditions for the maximum lipase production were determined using Plackett-Burman design and response surface methodology. The maximum lipase production, 1,980 U/ml was achieved at the optimum culture conditions. After purification, an 8.4-fold purity of lipase with specific activity of 5,647 U/mg protein and molecular mass of 39 kDa was obtained. The purified lipase was stable at pH 5.0-9.0 and temperature 30-80 °C. Ca(2+) and Triton X-100 showed stimulatory effect on the lipase activity. The purified lipase was highly stable in the non-polar solvents. The functional groups of the lipase were determined by Fourier transform-infrared (FT-IR) spectroscopy. The purified lipase showed higher hydrolytic activity towards CSO over the other cooked oil wastes. About 92.3 % of the CSO hydrolysis was observed by the lipase at the optimum time 3 h, pH 7.5 and temperature 35 °C. The hydrolysis of CSO obeyed pseudo first order rate kinetic model. The thermodynamic properties of the lipase hydrolysis were studied using the classical Van't Hoff equation. The hydrolysis of CSO was confirmed by FT-IR studies.
Subject(s)
Biotechnology/methods , Lipase/biosynthesis , Plant Oils/metabolism , Detergents , Hydrogen-Ion Concentration , Hydrolysis , Lipolysis , Molecular Weight , Octoxynol , Phylogeny , Solvents/chemistry , Spectroscopy, Fourier Transform Infrared , Sunflower Oil , Surface Properties , Temperature , ThermodynamicsABSTRACT
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.
