Characterization and properties of biosurfactants produced by a newly isolated strain Bacillus methylotrophicus DCS1 and their applications in enhancing solubility of hydrocarbon
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- 作者：Nawel Jemil ; Hanen Ben Ayed ; Noomen Hmidet…
- 关键词：Biosurfactants ; Screening ; Bacillus methylotrophicus DCS1 ; Characterization ; Diesel solubilization
- 刊名：World Journal of Microbiology & Biotechnology
- 出版年：2016
- 出版时间：November 2016
- 年：2016
- 卷：32
- 期：11
- 全文大小：1,024 KB
- 刊物类别：Chemistry and Materials Science
- 刊物主题：Chemistry
Applied Microbiology
Biotechnology
Biochemistry
Environmental Biotechnology
Microbiology - 出版者：Springer Netherlands
- ISSN：1573-0972
- 卷排序：32
文摘
Six biosurfactant-producing bacteria were isolated from hydrocarbon contaminated soils in Sfax, Tunisia. Isolates were screened for biosurfactant production by different conventional methods including hemolytic activity, surface tension reduction, drop-collapsing and oil displacement tests. All these screening tests show that all the isolates behave differently. Among the isolated bacteria, DCS1 strain was selected for further studies based on its highest activities and it was identified as Bacillus methylotrophicus DCS1. This strain was found to be a potent producer of biosurfactant when cultivated in mineral-salts medium supplemented with diesel oil (2 %, v/v) as a sole carbon source. Physicochemical properties and stability of biosurfactants synthesized by B. methylotrophicus DCS1 were investigated. The produced biosurfactants DCS1, from Landy medium, possess high surface activity that could lower the surface tension of water to a value of 31 from 72 mN m−1 and have a critical micelle concentration (CMC) of 100 mg L−1. Compared with SDS and Tween 80, biosurfactants showed excellent emulsification activities against different hydrocarbon substrates and high solubilization efficiency towards diesel oil. Biosurfactants DCS1 showed good stability in a wide range of temperature, pH and salinity. These results suggested that biosurfactants produced by B. methylotrophicus DCS1 could be an alternative to chemically synthesized surfactants for use in bioremediation processes to enhance the solubility of hydrophobic compounds.