Production of biosurfactants from Pseudomonas aeruginosa PA 1 isolated in oil environments

Abstract

-The potential production of rhamnolipid-type biosurfactants is assessed based on the development of a fermentative process with a strain of Pseudomonas aeruginosa PA1, which was isolated from oil production wastewater in the Northeast of Brazil. These production of molecules using different carbon (n-hexadecane, paraffinic oil, glycerol and babassu oil) and nitrogen sources (NaNO 3 , (NH 4 ) 2 SO 4 and CH 4 N 2 O) was studied. The best results were obtained when using glycerol as substrate. A C/N ratio of 60/1 and use of sodium nitrate as nitrogen source resulted in higher production of the rhamnolipid, expressed by rhamnose (3.16 g/L) and by the yield in relation to biomass (Yp/x = 0.70 g/g). Additionally, physical-chemical characteristics of the spent broth with and without cells were studied, providing a low critical micelle concentration of 19 mg/L and toxicity values of 13 and 13.8 mg/L using two test organisms, the micro crustacean Daphnia similis and the bacterium Vibrio fisheri (Microtox), respectively.

Production of a biosurfactant by Bacillus subtilis ICA56 aiming bioremediation of impacted soils

“…The crude biosurfactant (150 mg L −1 ) was serially diluted in distilled water to infinite dilution (absence of biosurfactant), reaching values close to surface tension of water (72.8 mN m −1 ) at 30 • C. The inflection in this graph represents the CMC [20].…”

“…Considering that a crude sample was assayed, it is a very satisfactory results, since commercial surfactin (Sigma) present CMC values ranging from 7.8 to 20.7 mg L −1 [30]. A low value of CMC indicates that a small amount of biosurfactant is required to obtain a high efficiency from these molecules in a process [20].…”

Studies on the Effects of Bioprocess Parameters and Kinetics of Rhamnolipid Production by P. aeruginosa NITT 6L

“…But after the attainment of stationary phase of cell growth, the production started to increase at a higher rate 21,22 and maximum product accumulation occurred after 96 h of cultivation (2.25 g L -1 corresponding to rhamnose concentration). 23 Rhamnolipid yield was then calculated by a coefficient of 3.4 obtained from the correlation of pure rhamonlipids/rhamnose (1.0 mg of rhamnose corresponds approximately to 3.4 mg of rhamnolipids). 24 The limitation of nitrogen in media favours the product accumulation in the culture broth.…”

Production of bioemulsifiers by Yarrowia lipolytica in sea water using diesel oil as the carbon source

“…These authors adopted the criteria used by Habba et al (2000): a good biosurfactant decreases the surface tension to a value equal to or less than 40mN/m. In other studies, P. aeruginosa LBI was able to produce rhamnolipid biosurfactant in the presence of soapstock (Moraes et al, 2002), diesel oil (Mariano et al, 2008) and n-hexadecane, glycerol, babassu oil and paraffin oil (Santa-Anna et al, 2002).…”