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Structural characterization of a biosurfactant produced by Bacillus subtilis at 45°C
Author(s) -
Makkar Randhir S.,
Cameotra Swaranjit S.
Publication year - 1999
Publication title -
journal of surfactants and detergents
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.349
H-Index - 48
eISSN - 1558-9293
pISSN - 1097-3958
DOI - 10.1007/s11743-999-0091-6
Subject(s) - surfactin , chemistry , pulmonary surfactant , bacillus subtilis , critical micelle concentration , surface tension , chromatography , lipopeptide , micelle , aqueous solution , thermophile , rhamnolipid , diesel fuel , microbial enhanced oil recovery , halophile , enhanced oil recovery , nuclear chemistry , chemical engineering , organic chemistry , bacteria , biochemistry , enzyme , microorganism , genetics , physics , quantum mechanics , engineering , pseudomonas aeruginosa , biology
Structural and biochemical characterization of a biosurfactant produced by Bacillus subtilis under thermophilic conditions was performed. Preliminary structural determination of CHCl 3 /CH 3 OH (65∶15) extracts by thin‐layer chromatographic reagents showed it to be identical to surfactin. Also, the infrared, 1 H nuclear magnetic resonance, and mass spectroscopy analysis confirmed it to be identical to surfactin. Biochemically, the surfactant was a lipopeptide‐containing lipid (17.05%) and protein (13.2%). The surfactant yielded a minimal aqueous surface‐tension value of 28 dyne/cm and an interfacial tension value at 0.1% concentration of 0.2 dyne/cm against diesel oil. The critical micelle concentration of the surfactant was 35 mg/L. The biosurfactant exhibited an emulsification value ( E 24 ) of 90 against diesel oil and a sand‐pack oil recovery of 62%. It has potential application in microbial‐enhanced oil recovery in thermophilic, alkaline, acidic, and halophilic environments.