Exploring Marine Environments To Unravel Tolerance Mechanisms To Relevant Compounds

Production of biofuels and chemicals using microorganisms has been a research driver in the last decades. The approach started with the engineering of metabolic pathways for production of compounds of interest, but it was soon realized that tolerance to the compounds being produced was one of the major bottlenecks of this approach. Since then, tolerance engineering of microbial cell factories along with metabolic pathway engineering has been one of the main research focuses. Microorganisms with natural tolerance to relevant compounds, such as ρ-coumaric, glutaric and isobutyric acids were isolated from Iranian sediment samples. This was achieved by replica plating the strains on plates containing high concentrations of the mentioned compounds. Thirty-two samples were analyzed and 96 strains isolated. Isolates with high tolerance were grown in presence of high concentrations of the compounds of interest, HPLC analyses were performed in order to distinguish between compound-degrading and tolerant bacteria. This led to the identification of seven tolerant and non-degrading isolates, the most interesting ones belonging to the genera Bacillus and Pseudomonas. These will be studied using genomic and transcriptomic approaches to identify the tolerance mechanisms used. Exploring new ecological niches, as contaminated marine environments allows the identification of naturally tolerant bacteria to the compounds of interest and most likely to the discovery of new mechanisms of tolerance.