Physicochemical characterization of biosurfactant and its potential to remove oil from soil and cotton cloth.

An alkaliphilic bacterium, Klebsiella sp. strain RJ-03, produced a biosurfactant, which showed low viscosity with pseudoplastic rheological behavior and exhibited emulsification activity with oils and hydrocarbons. The biosurfactant has excellent oil removing efficiency as compared to chemical surfactants. The isolated biosurfactant has compatibility with detergents and enhanced oil removing efficiency from soil and cotton cloths. It comprised of sugar, uronic acid, protein and sulfate. GC-MS analysis confirmed the presence of six monosaccharides (w/w), glucose (6.65%), galactose (23.98%), rhamnose (14.94%), mannose (17.54%), fucose (9.47%) and 6-O-Me-galactose (1.4%). It is a high molecular weight, thermostable biopolymer showing degradation above 300 °C. Positive ion reflector mode of MALDI TOF-TOF MS analysis revealed series of low and mid range mass peaks (m/z) corresponding to mono-, di-, tri- and oligo-saccharides content. The NMR, FT-IR, EDX-SEM, AFM and PSD analysis confirmed the presence of functional groups, bonds, elements and particle size respectively.

Jain RM ，Mody K ，Mishra A ，Jha B ... -  《-》

Effect of unconventional carbon sources on biosurfactant production and its application in bioremediation.

The potential of an alkaliphilic bacterium Klebsiella sp. strain RJ-03, to utilize different unconventional carbon sources for the production of biosurfactant was evaluated. The biosurfactant produced using corn powder, potato peel powder, Madhuca indica and sugarcane bagasse containing medium, exhibited significantly higher viscosity and maximum reduction in surface tension as compared to other substrates. Among several carbon substrates tested, production of biosurfactant was found to be the highest with corn powder (15.40 ± 0.21 g/l) as compared to others. The comparative chemical characterization of purified biosurfactant was done using advance analytical tools such as NMR, FT-IR, SEM, GPC, MALDI TOF-TOF MS, GC-MS, TG and DSC. Analyses indicated variation in the functional groups, monosaccharide composition, molecular mass, thermostability. Higher yield with cheaper raw materials, noteworthy stress tolerance of CP-biosurfactant toward pH and salt as well as compatibility with chemical surfactants and detergents revealed its potential for commercialization and application in bioremediation.

Jain RM ，Mody K ，Joshi N ，Mishra A ，Jha B ... -  《-》

Production and structural characterization of biosurfactant produced by an alkaliphilic bacterium, Klebsiella sp.: evaluation of different carbon sources.

The potential of an alkaliphilic bacterium Klebsiella sp. strain RJ-03, to utilize different carbon sources for the production of an extracellular biosurfactant was evaluated. Among the several carbon substrates tested, production of the crude biosurfactant was found to be the highest with starch (10.1±0.11g/L) followed by sucrose (5.1±0.11g/L), xylose (3.25±0.08g/L), galactose (3.1±0.16g/L) glucose (2.75±0.11g/L) and fructose (2.62±0.07g/L). The crude biosurfactant production was done using starch, sucrose, xylose, galactose and glucose containing medium, that exhibited significantly high viscosity, emulsification activity and maximum reduction in surface tension as compared to those obtained from fructose and maltose. The carbon source has significant effect on the quantity as well as the quality of biosurfactant production. The chemical characteristics of purified biosurfactant was compared by NMR, FT-IR, SEM, GPC, MALDI TOF-TOF MS, GC-MS, TG and DSC analysis, indicating variation in the functional groups, bonds, elements, monosaccharide composition, molecular mass and thermo stability.

Jain RM ，Mody K ，Joshi N ，Mishra A ，Jha B ... -  《-》

Structural and physicochemical characterization of crude biosurfactant produced by Pseudomonas aeruginosa SP4 isolated from petroleum-contaminated soil.

Pornsunthorntawee O ，Wongpanit P ，Chavadej S ，Abe M ，Rujiravanit R ... -  《BIORESOURCE TECHNOLOGY》

Physicochemical characterization of tensio-active produced by Geobacillus stearothermophilus isolated from petroleum-contaminated soil.

Biosurfactants are surface-active agents of microbial origin, and have a property of lowering the interfacial tension between two liquids. They act on the interface and are amphiphathic molecules; in with both hydrophilic and hydrophobic portions are present in the same molecule. However, the economics of producing biosurfactant has limited its commercial applications, and the costs can be reduced using cheap substrates or industrial waste. The present study showed the biosurfactant production using corn steep liquor and palm oil as carbon and nitrogen sources for reduction the costs of production. The biosurfactant production by Geobacillus stearothermophilus UCP 986 was carried out using optimized culture medium constituted by palm oil (7.5%) and corn steep liquor (4.5%) using Bioflo fermentor, at temperature of 45°C, during 32 h and agitation of 300 rpm. The biosurfactant showed a reduction of the water surface tension of 72-31 mN/m and interfacial tension of 0.3 mN/m. The biosurfactant was obtained from the net metabolic liquid by acetone precipitation corresponding to the yield of 2.3g/L. The isolate biosurfactant showed a CMC of 2.5% and non-ionic profile. The best emulsification index (E(24)) obtained was 87% using motor oil burned. The biosurfactant solution (2.5%) used in oil spreading test increases the viscosity of engine burning oil of 149.2% and 138.2% to vegetable fat post-frying, respectively. The gas chromatography-mass spectrometer indicated at 29.52 min a molecular weight of 207 Da and eight peaks by FT-IR identified the chemical structure of the biosurfactant produced by G. stearothermophilus.

Jara AM ，Andrade RF ，Campos-Takaki GM 《-》