Characterization of a lipopeptide biosurfactant produced by a crude-oil-emulsifying Bacillus sp. I-15
Petroleum-polluted environmental samples were collected to isolate and characterize biosurfactant-producing bacteria. Culturing of the collected samples in LB-broth and enrichments in chemically defined medium (CDM) with various carbon sources yielded 51 strains, some of which produced biosurfactant...
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Published in | International biodeterioration & biodegradation Vol. 84; pp. 168 - 178 |
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Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
Elsevier Ltd
01.10.2013
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Subjects | |
Online Access | Get full text |
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Summary: | Petroleum-polluted environmental samples were collected to isolate and characterize biosurfactant-producing bacteria. Culturing of the collected samples in LB-broth and enrichments in chemically defined medium (CDM) with various carbon sources yielded 51 strains, some of which produced biosurfactants/bioemulsifiers when challenged with crude oil as a sole carbon source. The I-15 isolate, a Gram-positive, motile bacillus, emulsified crude oil in CDM without reduction in surface tension. Compared to LB-grown cells, the crude oil-grown I-15 cells were surrounded by a transparent zone and produced heavily mucoid colonies on LB-agar plates. When grown with glucose as a sole carbon source, the I-15 strain produced a biosurfactant extracellularly, resulting in a 65% reduction in surface tension of the growth medium. The glucose-grown cells were coccoid to irregular in shape. Biosurfactant production was concomitant with reversible growth decline interrupting the exponential phase. Infrared spectroscopy and thin layer chromatography suggested a lipopeptide structure for the crude biosurfactant. Partial sequences of 10 16S rDNA gene clones from the I-15 strain were highly similar to those of various members of the family Bacillaceae. The I-15 strain is a promising biosurfactant producer and is probably an active indigenous crude oil degrader. Biosurfactant production is accompanied by morphological and physiological alterations. The I-15 strain possesses intragenomic heterogeneity in the rrn (RNA) operons.
► Isolation of a crude oil-emulsifying Bacillus sp. I-15. ► Growth-associated biosurfactant production from glucose. ► Morphological and physiological changes due to biosurfactant production. ► Microheterogeneity in 16S rDNA genes. |
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Bibliography: | http://dx.doi.org/10.1016/j.ibiod.2012.04.017 ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0964-8305 1879-0208 |
DOI: | 10.1016/j.ibiod.2012.04.017 |