Isolation, Optimization, and Structural Characterization of Glycolipid Biosurfactant Produced by Marine Isolate Shewanella algae B12 and Evaluation of Its Antimicrobial and Anti-biofilm Activity.

Biosurfactants are microbial-derived compounds with surface and emulsifying activities. Environmental and industrial applications make glycolipid biosurfactants particularly interesting among the several categories of biosurfactants. A potential glycolipid biosurfactant resource, Shewanella algae, was isolated from marine samples at the Persian Gulf. The glycolipid biosurfactant caused a reduction in water surface tension from 72 to 43 mN/m with a 0.25 mg/mL critical micelle concentration (CMC). Two-level factorial design was then applied for optimization of biosurfactant production, where a maximal reduction of culture broth surface tension (31 mN/m) acquired in the presence of crude oil (0.5%, v/v), NaNO3 (0.2 g/L), NH4Cl (0.7 g/L), and peptone (0.5 g/L). GC-MS analysis of the culture broth showed when crude oil was used as the sole carbon source, S. algae was able to degrade most of its alkane components. Nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectroscopy revealed the glycolipid structure of biosurfactant. The glycolipid biosurfactant exhibited considerable growth inhibition of clinical bacterial pathogens and disrupted the preformed biofilms of Bacillus cereus (83%), Streptococcus pneumoniae (53%), Pseudomonas aeruginosa (92%), Escherichia coli (64%), Klebsiella pneumoniae (87%), and Acinetobacter sp. (72%). In conclusion, the glycolipid biosurfactant secreted by S. algae exhibited a wide range of functional properties and was evidenced as a promising candidate for biomedical application.

Gharaei S ，Ohadi M ，Hassanshahian M ，Porsheikhali S ，Forootanfar H ... -  《-》

Glycolipopeptide biosurfactant from Bacillus pumilus SG: physicochemical characterization, optimization, antibiofilm and antimicrobial activity evaluation.

Gharaie S ，Ohadi M ，Hassanshahian M ，Shakibaie M ，Shahriary P ，Forootanfar H ... -  《3 Biotech》

Structural characterization and biological evaluation of Staphylosan (dimannooleate), a new glycolipid surfactant produced by a marine Staphylococcus saprophyticus SBPS-15.

Marine microbes have gained significant attention as potential biofactories for broad spectrum bioactive compounds. In the recent years, bioactive biosurfactants have warranted renewed interest from both environmental and clinical sectors as anti-biofilm agents due to their excellent properties of dispersing microbial biofilms. The present study explores a new glycolipid biosurfactant produced by a marine Staphylococcus saprophyticus exhibiting interesting biological activities. This glycolipid biosurfactant was purified and identified as Mannose-Mannose-Oleic acid (named as Staphylosan) based on the results of NMR, GC, GC-MS, MALDI-TOF-MS and tandem MS analysis. The surface tension and critical micelle concentration of purified Staphylosan was 30.9 mN m-1 and 24 mg L-1. Further, it showed promising biofilm inhibition and dislodging activities against a panel of profuse biofilm forming bacteria at both single and multi-species level which were isolated from boat hull biofilm environment such as Bacillus subtilis BHKH-7, Acinetobacter beijerinckii BHKH-11, Pseudomonas aeruginosa BHKH-19, Serratia liquefaciens BHKH-23, Marinobacter lipolyticus BHKH-31 and Micrococcus luteus BHKH-39. Moreover, it exhibited anionic charge and revealed non-toxicity towards brine shrimps, suggesting its environmental safety. This is a first report on Staphylosan, a multifunctional glycolipid surfactant from a marine Staphylococcus saprophyticus SBPS-15, exhibiting promising anti-biofilm activities and non-toxic in nature and thus finds possible potential use in many environmental applications especially under marine conditions.

Balan SS ，Mani P ，Kumar CG ，Jayalakshmi S ... -  《-》

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

Bharali P ，Konwar BK 《-》

Characterization of biosurfactant produced by the endophyte Burkholderia sp. WYAT7 and evaluation of its antibacterial and antibiofilm potentials.

The endophyte Burkholderia sp. WYAT7 isolated from the medicinal plant Artemisia nilagirica (Clarke) Pamp. was analyzed for its ability to produce biosurfactant. The evaluation of biosurfactant production was conducted using different screening methods which confirmed the presence of biosurfactant in the culture supernatant. CTAB- methylene blue agar plate method was used for the screening of glycolipid biosurfactant production. The biosurfactant produced by the bacteria effectively metabolized hydrocarbons present in the bacterial culture media. Fourier transform infrared spectroscopic (FTIR) analysis of biosurfactant provided the details regarding OH stretching, stretching vibrations of acyl chain, CO stretching, stretching vibrations of ether and vibrations of glycosidic linkages in the biosurfactant. The stretching vibrations of glycosidic linkage in the fingerprint regions of FTIR spectrum (1200 cm-1 to 800 cm-1 regions) confirms that the biosurfactant produced was a glycolipid. The GC-MS analysis confirmed the methyl and ethyl esters of fatty acids. The biosurfactant from the bacteria exhibited antibacterial activity against bacterial pathogens such as Pseudomonas aeruginosa (MTCC 2453), Escherichia coli (MTCC 1610), Salmonella paratyphi and Bacillus subtilis. The glycolipid biosurfactant had antibiofilm activity as evidenced in Staphylococcus aureus (MTCC 1430). All these results indicated the beneficial effect of the biosurfactant in plant-endophyte interactions. The properties exhibited by the biosurfactant suggest that it can be exploited commercially for the production of novel antibiotics.

A A ，E K R ，Mathew J 《-》