Production and characterization of biosurfactant from marine bacterium Inquilinus limosus KB3 grown on low-cost raw materials

Inquilinus limosus strain KB3, isolated from marine sediment in the south of Thailand, was used to produce a biosurfactant from a mineral salts medium (MSM) with palm oil decanter cake (PODC) as a carbon source. It was found that cellular growth and biosurfactant production in MSM were greatly affected by the medium components. I. limosus KB3 was able to grow and to produce surfactant reducing the surface tension of medium to 28.2 mN/m and giving a crude surfactant concentration of 5.13 g/l after 54 h. The biosurfactant obtained was found to reduce the surface tension of pure water to 25.5 mN/m with the critical micelle concentration of 9 mg/l, and retained its properties during exposure to elevated temperatures (121 °C), high salinity (12 % NaCl), and a wide range of pH values. Chemical characterization by FT-IR, NMR, and ESI-MS revealed that the biosurfactant has a lipopeptide composition with molecular mass (m/z) of 1,032. The biosurfactant was capable of forming stable emulsions with various hydrocarbons and had the ability to enhance oil recovery, PAHs solubility, and antimicrobial activity.     

Utilization of palm oil decanter cake as a novel substrate for biosurfactant production from a new and promising strain of Ochrobactrum anthropi 2/3

A biosurfactant-producing bacterium, isolate 2/3, was isolated from mangrove sediment in the south of Thailand. It was evaluated as a potential biosurfactant producer. The highest biosurfactant production (4.52 g/l) was obtained when the cells were grown on a minimal salt medium containing 25 % (v/v) palm oil decanter cake and 1 % (w/v) commercial monosodium glutamate as carbon and nitrogen sources, respectively. After microbial cultivation at 30 °C in an optimized medium for 96 h, the biosurfactant produced was found to reduce the surface tension of pure water to 25.0 mN/m with critical micelle concentrations of 8.0 mg/l. The stability of the biosurfactant at different salinities, pH and temperature and also its emulsifying activity was investigated. It is an effective surfactant at very low concentrations over a wide range of temperatures, pH and salt concentrations. The biosurfactant obtained was confirmed as a glycolipid type biosurfactant by using a biochemical test, fourier-transform infrared spectroscopy, MNR and mass spectrometry. The crude biosurfactant showed a broad spectrum of antimicrobial activity and also had the ability to emulsify oil and enhance polyaromatic hydrocarbons solubility.     

Isolation and functional characterization of a biosurfactant produced by a new and promising strain of Oleomonas sagaranensis AT18

Biosurfactant-producing bacteria were isolated from mangrove sediment in southern Thailand. Isolates were screened for biosurfactant production by using the surface tension test. The highest reduction of surface tension was achieved with a bacterial strain which was identified by 16S rRNA gene sequencing as Oleomonas sagaranensis AT18. It has also been investigated using different carbon and nitrogen sources. It showed that the strain was able to grow and reduce the surface tension of the culture supernatant to 25?mN/m. In all 5.30?g of biosurfactant yield was obtained after 54?h of cultivation by using molasses and NaNO(3) as carbon and nitrogen sources, respectively. The biosurfactant recovery by chloroform:methanol extraction showed a small critical micelle concentration value (8?mg/l), thermal and pH stability with respect to surface tension reduction. It also showed emulsification activity and a high level of salt concentration. The biosurfactant obtained was confirmed as a glycolipid by using a biochemical test, FT-IR and mass spectra. The crude biosurfactant showed a broad spectrum of antimicrobial activity and also had the ability to emulsify oil and enhance PAHs solubility.     

Isolation and characterization of a biosurfactant from Deinococcus caeni PO5 using jackfruit seed powder as a substrate

Biosurfactant-producing bacteria were isolated from various sources in the south of Thailand. Isolates were screened for biosurfactant production using jackfruit seed powder (JSP) as a novel and promising substrate. The highest biosurfactant activity was obtained with a bacterial strain which was identified by 16S rRNA gene sequence analysis as Deinococcus caeni PO5. D. caeni PO5 was able to grow and reduce the surface tension of the culture supernatant from 67.0 to 25.0 mN/m after 87 h of cultivation when 40 g/l of JSP and 1 g/l of commercial monosodium glutamate were used as carbon and nitrogen sources, respectively. The biosurfactant obtained by ethyl acetate extraction showed high surface tension reduction (47.0 mN/m), a small critical micelle concentration value (8 mg/l), thermal and pH stability with respect to surface tension reduction and emulsification activity, and a high level of salt tolerance. Chemical characterization by biochemical testing, Fourier transform infrared spectroscopy, and mass spectra revealed that the obtained biosurfactant was a glycolipid-type biosurfactant. The obtained biosurfactant was capable of forming stable emulsions with various hydrocarbons and had the ability to enhance oil recovery, the solubility of polyaromatic hydrocarbons, heavy metal removal, and antimicrobial activity.     

An efficient biosurfactant-producing bacterium Selenomonas ruminantium CT2, isolated from mangrove sediment in south of Thailand

Biosurfactant-producing bacteria, isolate CT2, was isolated from mangrove sediment in the south of Thailand. The sequence of the 16S rRNA gene from isolate CT2 showed 100?% similarity with Selenomonas ruminantium. The highest biosurfactant production (5.02?g/l) was obtained when the cells were grown on minimal salt medium containing 15?g/l molasses and 1?g/l commercial monosodium glutamate supplemented with 1?g/l NaCl, 0.1?g/l leucine, 5?% (v/v) inoculum size at 30?°C and 150?rpm after 54?h of cultivation. The biosurfactant obtained by extraction with ethyl acetate showed high surface tension reduction (25.5?mN/m), a small CMC value (8?mg/l), thermal and pH stability with respect to surface tension reduction and emulsification activity and a high level of salt tolerance. The biosurfactant obtained was confirmed as a lipopeptide by using a biochemical test, FT-IR, MNR and mass spectrometry. The crude biosurfactant showed a broad spectrum of antimicrobial activity and also had the ability to emulsify oil and enhance PAHs solubility.