Avaliação do crescimento bacteriano em inibidores de incrustações

Abstract

A series of complex procedures are used to extract oil, aiming to extract the maximum of these reserves. Many of these oil recovery techniques rely on well stimulation by fluid injection and are classified as enhanced oil recovery (EOR) methods. These assist in breaking the hydrocarbon chains by improving the fluidity of the oil and gas to the wellhead, with recovery of up to 40% of the total oil in the reservoir. However, many of these compounds contain carbon, nitrogen and phosphorus, among other elements that serve as substrate, as stimulants or as inhibitors factors for microorganisms' growth that cause damage such as scale and corrosion. Phosphonates are a chemical class widely used as scale inhibitor. The aim of this work is to verify microbial strains capable of using phosphonate-based additives as a nutrient source leading to their degradation. The microorganisms selected for the experiment were Pseudomonas ATCC 27583, Pseudomonas aeruginosa and Shewanella algae, both of environmental origin. To do so, the composition of the ideal culture medium was established for each microorganism, as well as the concentration of inoculum to be used and the concentration of the additive used in the tests. Then, the microbial growth was monitored under the determined culture conditions, in the presence and absence of phosphonate. The tests were performed in a 96-well microplate reader (Biotec® - Synergy2). In each well, 100 μl of medium was added to the inoculum under different assay conditions. The equipment was configured to perform the reading at wavelength of 600 nm, with 40-minute reading intervals. The results showed different degrees of growth of the three microbial species, depending on the composition of the medium and the phosphonate used. Moreover, the use of the additives as a source of nutrient (phosphorus, nitrogen and carbon) was observed for each species.