Enhanced Biodegradation of Lindane Using Oil-in-Water Bio-Microemulsion Stabilized by Biosurfactant Produced by a New Yeast Strain, Pseudozyma VITJzN01
ABSTRACT Organochlorine pesticide residues continue to remain as a major environmental threat worldwide. Lindane is an organochlorine pesticide widely used as an acaricide in medicine and agriculture. In the present study, a new lindane degrading yeast strain, Pseudozyma VITJzN01 was identified as copious producer of glycolipid biosurfactant. The glycolipid structure and type was elucidated by FTIR, NMR spectroscopy and GC-MS analysis. The surface activity and stability of glycolipid was analyzed. The glycolipids characterized as mannosylerythritol lipids (MELs) exhibited excellent surface active properties and the surface tension of water was reduced to 29 mN/m. The glycolipid was stable over a wide range of pH, temperature and salinity, showing a very low CMC of 25 mg/l. Bio-microemulsion of olive oil-in-water (O/W) was prepared using the purified biosurfactant without addition of any synthetic cosurfactants, for lindane solubilization and enhanced degradation assay in liquid and soil slurry. The O/W bio-microemulsions enhanced the solubility of lindane up to 40 folds. Degradation of lindane (700 mg/l) by VITJzN01 in liquid medium amended with bio-microemulsions was found to be enhanced by 36% in 2 days, compared to degradation in 12 days in the absence of bio-microemulsions. Lindane spiked soil slurry incubated with bio-microemulsions also showed 20-40% enhanced degradation compared to the treatment with glycolipids or yeast alone. This is the first report on lindane degradation by Pseudozyma sp., and application of bio-microemulsions for enhanced lindane degradation. MEL stabilized bio-microemulsions can serve as a potential tool for enhanced remediation of diverse lindane contaminated environments.
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ABSTRACT: A single step photometric micromethod for determination of fatty acids in lipids in benzene solution, using rhodamine 6G reagent, has been developed. The method eliminates the disadvantage of formation of a biphasic system and is applicable in the presence of glycerides, sterols, epoxy compounds, hydrocarbons and long chain hydroxy compounds such as long chain fatty alcohols. The long chain fatty acids from C12 to C22, both saturated and unsaturated, can be determined with reasonable accuracy in the concentration range of 0.08–0.25 µmole/ml. The method is simple, rapid, and requires relatively inexpensive chemicals.Journal of Oil & Fat Industries 01/1969; 46(9):473-475. DOI:10.1007/BF02544370 · 1.62 Impact Factor
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ABSTRACT: Herein we report the structure and selected properties of a new class of biosurfactants that we have named the flavolipids. The flavolipids exhibit a unique polar moiety that features citric acid and two cadaverine molecules. Flavolipids were produced by a soil isolate, Flavobacterium sp. strain MTN11 (accession number AY162137), during growth in mineral salts medium, with 2% glucose as the sole carbon and energy source. MTN11 produced a mixture of at least 37 flavolipids ranging from 584 to 686 in molecular weight (MW). The structure of the major component (23%; MW = 668) was determined to be 4-[[5-(7-methyl-(E)-2-octenoylhydroxyamino)pentyl]amino]-2-[2-[[5-(7-methyl-(E)-2-octenoylhydroxyamino)pentyl]amino]-2-oxoethyl]-2-hydroxy-4-oxobutanoic acid. The partially purified flavolipid mixture isolated from strain MTN11 exhibited a critical micelle concentration of 300 mg/liter and reduced surface tension to 26.0 mN/m, indicating strong surfactant activity. The flavolipid mixture was a strong and stable emulsifier even at concentrations as low as 19 mg/liter. It was also an effective solubilizing agent, and in a biodegradation study, it enhanced hexadecane mineralization by two isolates, MTN11 (100-fold) and Pseudomonas aeruginosa ATCC 9027 (2.5-fold), over an 8-day period. The flavolipid-cadmium stability constant was measured to be 3.61, which is comparable to that for organic ligands such as oxalic acid and acetic acid. In summary, the flavolipids represent a new class of biosurfactants that have potential for use in a variety of biotechnological and industrial applications.Applied and Environmental Microbiology 02/2004; 70(1):114-20. DOI:10.1128/AEM.70.1.114-120.2004 · 3.95 Impact Factor
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ABSTRACT: An efficient biosurfactant-producing bacterium was isolated and cultured from petroleum reservoir in northeast China. Isolate was screened for biosurfactant production using haemolytic assay, Cetyl Trimethyl Ammonium Bromide agar plate assay (CTAB) and the qualitative oil-displacement test. Based on partial sequenced 16S rDNA analysis of isolate, USTBa, identified as Bacillus methylotrophicus with 100% identity. This bacterium was able to produce a type of biosurfactant with excessive foam-forming properties. The maximum biosurfactant production was obtained when the cells were grown on minimal salt medium containing 2% (v/v) crude-oil as the sole source of carbon at 35 ◦C and 180 rpm after 192 h. This strain had a high emulsification activity and biosurfactant production of 78% and 1.8 g/L respectively. The cell free broth containing biosurfactant could reduce the surface tension to 28 mN/m. Fourier transform infrared (FT-IR) spectrum of extracted biosurfactant indicates the presence of carboxyl, hydroxyl and methoxyl functional groups. Elemental analysis of the biosurfactant by Energy dispersive X-ray spectroscopy (EDS) reveals that the biosurfactant was anionic in nature. The strain USTBa represented as a potent biosurfactant-producer and could be useful in variety of biotechnological and industrial processes, particularly oil industry.Biochemical Engineering Journal 05/2013; 74. DOI:10.1016/j.bej.2013.02.018 · 2.37 Impact Factor