Enhancement of Biosurfactant Production by Bacteria Isolated from Crude Oil through Adaptation Laboratory Evolution

Biosurfactant is widely used in the petroleum industry since it can increase oil recovery. However, its productivity remains economically inefficient. Through the adaptation laboratory evolution (ALE), it is possible to improve the biosurfactant productivity of targeted bacteria. This study aimed to enhance biosurfactant production by bacteria through the ALE and characterize the biosurfactant properties. Cetyltrimethylammonium bromide (CTAB) was used as a mutagen at concentrations ranging from 3.9 ppm to 10 ppm. The biosurfactant characterizations conducted were: 1) interfacial surface tension (IFT), 2) emulsification index (E-24), and 3) biosurfactant structure. The biosurfactant activity from the CTAB-resistant strain (KG7') had 3.3 folds higher IFT reduction with increasing production yield (Y-p/x) up to 2.6 folds (18.75 +/- 1.53 mg/10(8) CFU) compared to wildtype (WT) (7.07 +/- 0.89 mg/10(8) CFU). The KG7', which was resistant at 4.5 ppm CTAB (KG7'b), was stable after the extension of the ALE process and had higher biosurfactant activity than WT. The structural properties of WT and mutant biosurfactants were both belong to the lipopeptide class. As a result, the ALE offers a potential tool for enhancing bacterial biosurfactant production.

Automated summary

Through adaptation laboratory evolution (ALE), biosurfactant productivity can be improved, with CTAB-resistant strains showing higher yields and activity compared to wildtype strains.