Isolation of biosurfactant producers, optimization and properties of biosurfactant produced by Acinetobacter sp. from petroleum-contaminated soil.

To screen and identify biosurfactant producers from petroleum-contaminated soil; to use response surface methodology (RSM) for medium optimization to enhance biosurfactant production; and to study the properties of the newly obtained biosurfactant towards pH, temperature and salinity. We successfully isolated three biosurfactant producers from petroleum-contaminated soil and identified them through 16S rRNA sequence analysis, which exhibit the highest similarities to Acinetobacter beijerinckii (100%), Kocuria marina (99%) and Kineococcus marinus (99%), respectively. A quadratic response model was constructed through RSM designs, leading to a 57·5% increase of the growth-associated biosurfactant production by Acinetobacter sp. YC-X 2 with an optimized medium: beef extract 3·12 g l(-1) ; peptone 20·87 g l(-1) ; NaCl 1·04 g l(-1); and n-hexadecane 1·86 g l(-1). Biosurfactant produced by Acinetobacter sp. YC-X 2 retained its properties during exposure to a wide range of pH values (5-11), high temperatures (up to 121°C) and high salinities [up to 18% (w/v) Na(+) and Ca(2+) ], which was more sensitive to Ca(2+) than Na(+). Two novel biosurfactant producers were isolated from petroleum-contaminated soil. Biosurfactant from Acinetobacter sp. YC-X 2 has good properties to a wide range of pH, high temperature and high salinity, and its production was optimized successfully through RSM. The fact, an increasing demand of high-quality surfactants and the lack of cost-competitive bioprocesses of biosurfactants for commercial utilization, motivates researchers to develop cost-effective strategies for biosurfactant production through isolating new biosurfactant producers with special surface-active properties and optimizing their cultural conditions. Two novel biosurfactant producers in this study will widen our knowledge about this kind of micro-organism. This work is the first application of RSM designs for cultural optimization of biosurfactant produced by Acinetobacter genus and the first report that biosurfactant may be more sensitive to Ca(2+) than Na(+) .

Chen J ，Huang PT ，Zhang KY ，Ding FR ... -  《-》

Optimization and characterization of biosurfactant from Streptomyces griseoplanus NRRL-ISP5009 (MS1).

This work aimed to study, isolate, characterize and stabilize the biosurfactant isolated from actinomycetes found in petroleum contaminated soil. Optimized production of the biosurfactant from Streptomyces griseoplanus NRRL-ISP5009, SM1 was obtained on day 6 at 30°C, pH 7, 150 rev min-1 , in glycerol yeast extract broth medium supplemented with cellulose, yeast extract and 1% NaCl. The stability of the biosurfactant produced was studied at different temperatures, pH and different concentrations of NaCl. The produced biosurfactant was extracted and purified. Streptomyces griseoplanus NRRL-ISP5009, SM1 isolated from oil contaminated soil produced a biosurfactant exhibiting emulsification activity. The produced biosurfactant is a mixture of carbohydrate, lipid and protein. It has promising characteristics, including a higher stability at alkaline pH than at acidic pH, a salinity of 1-3% and stable in the temperature range from 0 and 100°C. Also, the potential antimicrobial activity of the purified biosurfactant was recorded. The research was focused on the isolation of a novel source of biosurfactants that have great importance in the manufacture of food, detergent, pharmaceutical and cosmetics.

Elkhawaga MA 《-》

Lipopeptide biosurfactant production bacteria Acinetobacter sp. D3-2 and its biodegradation of crude oil.

Bao M ，Pi Y ，Wang L ，Sun P ，Li Y ，Cao L ... -  《-》

Production of lipopeptide biosurfactants by Bacillus atrophaeus 5-2a and their potential use in microbial enhanced oil recovery.

Zhang J ，Xue Q ，Gao H ，Lai H ，Wang P ... -  《Microbial Cell Factories》

Production and characterization of surfactin-like biosurfactant produced by novel strain Bacillus nealsonii S2MT and it's potential for oil contaminated soil remediation.

Phulpoto IA ，Yu Z ，Hu B ，Wang Y ，Ndayisenga F ，Li J ，Liang H ，Qazi MA ... -  《Microbial Cell Factories》