Adaptive evolution of Bacillus subtilis for biosurfactant production

Abstract

Surfactins are surfactants produced by microorganisms that combine effective activity with low toxicity and high biodegradability. Compounds like this type have great industrial interest, especially in the green chemistry area. The green chemistry industry has grown in line with increasing concerns related to the environmental impacts of human actions. However, the productivity of natural strains of Bacillus subtilis, surfactin-producing bacteria, is insufficient for the economic viability of industrial production. And even attempts to optimize the production process have not been sufficient to reach the minimum required levels. Genetic approaches are necessary, but they come up against the obstacle of the microorganism's susceptibility to the biosurfactant, which ends up being toxic to cells when a threshold is reached. In this context, this project proposes the use of the adaptive evolution laboratory technique of B. subtilis to produce biosurfactants. In Brazil, a strain previously modified by rational design was exposed to different concentrations of surfactin, and the potential mutants were sequenced and they will be analyzed and characterized genetically using bioinformatics tools. With the help of techniques developed in the laboratory specializing in biosurfactants in Germany and the knowledge of the International Supervisor collaborating on this project, the mutations will be reproduced, through CRISPR-Cas9 genetic editing, aiming to build a bacterial chassis more resistant to surfactin. Scale-up in bioreactors will also be tested and improved. The proposed modifications are innovative, intending to make the production of surfactin more industrially viable, in addition to benefiting from closer partnerships with internationally renowned institutions in the area.