Browsing by Author "Gamal El Din, Shereen"

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    Production and Characterization of Biosurfactants Produced by Bacillus spp and Pseudomonas spp Isolated from the Rhizosphere Soil of an Egyptian Salt Marsh Plant
    (Nature and Science, 2013) Diab, Ali; Gamal El Din, Shereen
    Seventeen bacterial strains were isolated from the rhizosphere soil of an Egyptian salt marsh plant and screened for biosurfactant production. 76.5 % of the bacterial strains were found to produce biosurfactants, they were identified as Bacillus spp (4 strains) and Pseudomonas spp (9 strains), of which P. aeruginosa was represented by 6 strains. From the preliminary experiment, (Bacillus SH 20, SH 26 and Pseudomonas aeruginosa SH 29, SH 30) were the most active biosurfactant producers. The four main active biosurfactant producers were selected and studied. The results showed that P. aeruginosa SH 29 represents a good candidate for the production of the biosurfactants when grown on both nutrient broth (NB) and inorganic salt media (ISM) supplemented with waste frying oil. On the other hand Bacillus spp (SH 20 and SH26) were active biosurfactant producers when grown on molasses. Waste frying oil and molasses represent good, cheap and easily available substrates which have the advantage of reducing the production cost and help economic production of biosurfactants. The results of using different vegetable oils varied with the variation of media and bacterial strains. Olive oil was promising followed by sunflower oil and soybean oil. All of the four bacterial strains were able to emulsify the studied hydrocarbon oils and vegetable oils but with different E24 values. Bacillus spp SH 20, SH 26 produced the highest E24 values for petroleum oil (84.4 ± 5.2 and 75.0 ± 5.6 % respectively). This was followed by P. aeruginosa SH 30 (66.7 ± 3.8 %) and P. aeruginosa SH 29 (62.0 ± 3.4 %). The results also showed that the produced biosurfactants in the present study were stable at 0-121 °C, pH 1-14 values and at different concentrations of NaCl. An attempt was made to isolate the biosurfactant produced by P. aeruginosa SH 29 when grown in waste frying oil (2% w/v). The production yield of this crude product was estimated as 2.8 g/L. This crude material was selected and kept for further purification and studies. Accordingly, the four bacterial strains may be useful in petroleum industry (e.g petroleum recovery, cleaning of oil storage tanks and recovery of oil from oily sludge) and they may help in bioremediation of oil contaminated sites. [Ali Diab and Shereen Gamal El Din. Production and Characterization of Biosurfactants Produced by Bacillus spp and Pseudomonas spp Isolated from the Rhizosphere Soil of an Egyptian Salt Marsh Plant. Nat Sci 2013;11(5):103-112]. (ISSN: 1545-0740). http://www.sciencepub.net.