«STUDY OF THE INFLUENCE OF QUORUM SENSING ON RHAMNOLIPIDS BIOSYNTHESIS BY Pseudomonas aeruginosa LBI 2A1 AND IMPROVEMENT OF THE PRODUCTION PROCESS

Abstract

Rhamnolipids (Rhls) are biosurfactants mainly produced by the bacterium Pseudomonas aeruginosa and which have high surface activity. The production of this surfactant is regulated by a cascade system of quorum sensing and physical-chemical environmental factors. The mutant strain P. aeruginosa LBI 2A1 has shown good results in the production of RLs with an increase of 70% compared to the wild strain when using hydrophobic sources. However, the site and type of mutation of this microorganism have not yet been investigated. This study can help in changing the scale to the industrial production of Rhls, which still has gaps related to low yield and high production cost. Understanding the bioprocess is essential to overcome these challenges, both on the micro scale - study of metabolism and responsible genes - and on the macro scale - influence of physicochemical parameters, development of mechanisms to control foam and feedbatch. Therefore, this research seeks to study the influence of quorum sensing on the biosynthesis of rhamnolipids by P. aeruginosa LBI 2A1 relating the genetics of the microorganism and environmental factors. And also, to improve the bioprocess in reactor using optimized conditions in order to contain the foam formation and to study the carbon flux. For this, the genetic alteration will be investigated by sequencing and subsequent intentional mutation in the wild strain. In the production of Rhls, different fatty acids will be used, in addition to a residual source from the fruit refinery. The process will be optimized with the aid of experiment design. The analyzes will rely on the aid of HPLC, LC-MS, GC-MS for quantification of metabolites and consumption of carbon source.