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

Microbial Cell Factories

Research

Ping Wang¹  Quanhong Xue²  Hangxian Lai²  Hui Gao²  Junhui Zhang² 

[1] College of Earth Sciences and Resources, Chang’an University, 710055, Xi’an, China;College of Natural Resources and Environment, Northwest A & F University, 3 Taicheng Road, 712100, Yangling, China;

关键词: Microbial enhanced oil recovery;    Biosurfactant;    Bacillus atrophaeus;    Surface tension;    Crude oil removal;   

DOI  :  10.1186/s12934-016-0574-8

 received in 2016-04-25, accepted in 2016-09-28,  发布年份 2016

来源: Springer

【 摘 要 】

BackgroundLipopeptides are known as promising microbial surfactants and have been successfully used in enhancing oil recovery in extreme environmental conditions. A biosurfactant-producing strain, Bacillus atrophaeus 5-2a, was recently isolated from an oil-contaminated soil in the Ansai oilfield, Northwest China. In this study, we evaluated the crude oil removal efficiency of lipopeptide biosurfactants produced by B. atrophaeus 5-2a and their feasibility for use in microbial enhanced oil recovery.ResultsThe production of biosurfactants by B. atrophaeus 5-2a was tested in culture media containing eight carbon sources and nitrogen sources. The production of a crude biosurfactant was 0.77 g L−1 and its surface tension was 26.52 ± 0.057 mN m−1 in a basal medium containing brown sugar (carbon source) and urea (nitrogen source). The biosurfactants produced by the strain 5-2a demonstrated excellent oil spreading activity and created a stable emulsion with paraffin oil. The stability of the biosurfactants was assessed under a wide range of environmental conditions, including temperature (up to 120 °C), pH (2–13), and salinity (0–50 %, w/v). The biosurfactants were found to retain surface-active properties under the extreme conditions. Additionally, the biosurfactants were successful in a test to simulate microbial enhanced oil recovery, removing 90.0 and 93.9 % of crude oil adsorbed on sand and filter paper, respectively. Fourier transform infrared spectroscopy showed that the biosurfactants were a mixture of lipopeptides, which are powerful biosurfactants commonly produced by Bacillus species.ConclusionsThe study highlights the usefulness of optimization of carbon and nitrogen sources and their effects on the biosurfactants production and further emphasizes on the potential of lipopeptide biosurfactants produced by B. atrophaeus 5-2a for crude oil removal. The favorable properties of the lipopeptide biosurfactants make them good candidates for application in the bioremediation of oil-contaminated sites and microbial enhanced oil recovery process.

【 授权许可】

CC BY   
© The Author(s) 2016