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 ... -  《-》

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 ... -  《-》

Substrate dependent production of extracellular biosurfactant by a marine bacterium.

Das P ，Mukherjee S ，Sen R 《-》

Production and physico-chemical characterization of a biosurfactant produced by Pseudomonas aeruginosa OBP1 isolated from petroleum sludge.

Bharali P ，Konwar BK 《-》

Biosurfactant production by Bacillus subtilis B30 and its application in enhancing oil recovery.

The fermentative production of biosurfactants by Bacillus subtilis strain B30 and the evaluation of biosurfactant based enhanced oil recovery using core-flood were investigated. Different carbon sources (glucose, sucrose, starch, date molasses, cane molasses) were tested to determine the optimal biosurfactant production. The isolate B30 produced a biosurfactant that could reduce the surface tension and interfacial tension to 26.63±0.45 mN/m and 3.79±0.27 mN/m, respectively in less than 12h in both glucose or date molasses based media. A crude biosurfactant concentration of 0.3-0.5 g/l and critical micelle dilution (CMD) values of 1:8 were observed. The biosurfactants gave stable emulsions with wide range of hydrocarbons including light and heavy crude oil. The biosurfactants were partially purified and identified as a mixture of lipopeptides similar to surfactin, using high performance thin layer chromatography and Fourier transform infrared spectroscopy. The biosurfactants were stable over wide range of pH, salinity and temperatures. The crude biosurfactant preparation enhanced light oil recovery by 17-26% and heavy oil recovery by 31% in core-flood studies. The results are indicative of the potential of the strain for the development of ex situ microbial enhanced oil recovery processes using glucose or date molasses based minimal media.

Al-Wahaibi Y ，Joshi S ，Al-Bahry S ，Elshafie A ，Al-Bemani A ，Shibulal B ... -  《-》