Volume 8, Issue 4 (11-2010)
Abstract
Biosurfactants are surface active agents which are widely used in industries. One of the important varieties of biosurfactants are widely produced by Pseudomonas aeruginosa. In this paper. P. aeruginosa MM1011 was obtained from Persian Type Culture Collection (Biotechnology Department, IROST). The aim of this investigation is to optimize the mineral salts medium with whey to produce rhamnolipid. Since P. aeruginosa is Lac (-), the whey hydrolysed by lactase in order to produc glucose as carbon source. The results assayed by phenol-sulfuric acid method and crude oil emulsification activity. Depicted results showed that the best medium is 3M which contained whey (that hydrolysed by lactase completely at temp.: 40° C ,pH: 6.5, time: 3 hours) . The product obtained at temp.: 33 ° C, pH:7, shaking rate: 200 rpm , nitrogen concentration, 0.36 %, and inoculum size, 2 %. The results of rhamnolipid production by usig whey as a source of carbon and energy is more or less comparable with the results obtained when molasses was used as carbon and energy source.
Volume 9, Issue 3 (10-2010)
Abstract
Biosurfactants are products of broad range of microorganisms. These compounds are surface active. Glycolipids, Phospholipids & Fatty acids, Lipopeptids and Lipoproteins, Polymeric biosurfactants and Special Biosurfactants are main types of biosurfactants. Rhamnolipid is a type of Glycolipids that is produced by Pseudomonas aeruginosa. In the present paper, P. aeruginosa MM1011 was obtained from Persian Type Culture Collection (Biotechnology Center, IROST). The aim of this investigation was optimization of mineral salts medium with sugar beet molasses to produce rhamnolipid considering specific parameters. such as: C/N, Temperature, pH, shaking rate, and Inoculation size. Since P. aeruginosa is Suc.(-), it was mutated to be able to use the sucrose as carbon source. The molasses treated chemically, then used by the bacterium. The results assayed by phenol-sulfuric acid method, and crude oil emulsification capability. Results of ANOVA. Depicted results showd that the optimum conditions without molasses is: temp.:33˚c, pH 7, C/N:18, shaking rate: 200 rpm and inoculom: 2% in 96 hours and the best medium is 3M which contained sugar beet molasses. Further investigation proved that the best production temperature is 33°c when pH is 6.8, shaking rate: 200 rpm, C/N: 16, inoculom: 2%. Using the above mentioned factors, the obtained results showed that the produced rhamnose was 0.22 g/L (rhamnolipid = 0.66 g /L) and crude oil emulcification was 55.5 %.
