Improved Biosurfactant Production by Bacillus subtilis SPB1 Mutant Obtained by Random Mutagenesis and Its Application in Enhanced Oil Recovery in a Sand System

• Published in: Journal of microbiology and biotechnology Vol. 28; no. 1; pp. 95 - 104
• Main Authors: Bouassida, Mouna, Ghazala, Imen, Ellouze-Chaabouni, Semia, Ghribi, Dhouha
• Format: Journal Article
• Language: English
• Published: Korea (South) 한국미생물·생명공학회 28-01-2018
• Subjects: Bacillus subtilis - drug effects; Bacillus subtilis - genetics; Bacillus subtilis - metabolism; Bacillus subtilis - radiation effects; Fermentation; Hydrogen-Ion Concentration; Industrial Microbiology - methods; Metabolic Engineering; Mutagenesis; Nitrous Acid; Oil and Gas Industry - methods; Surface-Active Agents - metabolism; Temperature; Ultraviolet Rays; 생물학; fermentation; Bacillus subtilis; Random mutagenesis; biosurfactant; oil recovery
• ISSN: 1017-7825; 1738-8872
• DOI: 10.4014/jmb.1701.01033

Biosurfactants or microbial surfactants are surface-active biomolecules that are produced by a variety of microorganisms. Biodegradability and low toxicity have led to the intensification of scientific studies on a wide range of industrial applications for biosurfactants in the field of environmental bioremediation as well as the petroleum industry and enhanced oil recovery. However, the major issues in biosurfactant production are high production cost and low yield. Improving the bioindustrial production processes relies on many strategies, such as the use of cheap raw materials, the optimization of medium-culture conditions, and selecting hyperproducing strains. The present work aims to obtain a mutant with higher biosurfactant production through applying mutagenesis on
SPB1 using a combination of UV irradiation and nitrous acid treatment. Following mutagenesis and screening on blood agar and subsequent formation of halos, the mutated strains were examined for emulsifying activity of their culture broth. A mutant designated
M2 was selected as it produced biosurfactant at twice higher concentration than the parent strain. The potential of this biosurfactant for industrial uses was shown by studying its stability to environmental stresses such as pH and temperature and its applicability in the oil recovery process. It was practically stable at high temperature and at a wide range of pH, and it recovered above 90% of motor oil adsorbed to a sand sample.