Avaliação da ação antimicrobiana do extrato pirolenhoso neutralizado e bidestilado

Abstract

Wood vinegar (WV) is a co-product generated in the pyrolysis process of plant biomass that can have a range of applications. Among these applications, it is used as an antimicrobial agent. However, there are statements that limit the antimicrobial action that EP performs only to the fraction of organic acids present in its chemical composition, raising doubts as to its efficiency as a whole. Thus, the objective of this research was to evaluate the antimicrobial activity of WV, test the influence of its pH on this activity, evaluate the chemical composition of this product and record images of scanning electron microscopy (SEM) of microbial cells. Antimicrobial evaluations to determine the Minimum Inhibitory Concentration (MIC) were performed in vitro by the broth microdilution method. For the Minimum Bactericidal and Fungicide Concentrations (MBC and MFC) the agar growth method was used. The chemical composition of WV and its concentrate was determined by gas chromatography and mass spectrometry and the SEM images were obtained with the aid of an electron microscope (Pfeiffer Vacuum – D-35614 Assiar). Statistical analyzes were performed using regression analysis using the R software (version 4.1.3). The results obtained showed that even at neutral pH, WV proved to be effective as an antimicrobial, proving that its action is not limited to a single class of compounds, but to all of them. However, the increase in neutralization influenced the WV concentrations required for the inhibition of the evaluated microorganisms. Both WV obtained from B. vulgaris and E. urograndis played a satisfactory antimicrobial role, inhibiting the development of all tested microorganisms. SEM images demonstrated that WV influences the morphology of the cell wall of microorganisms, resulting in alterations in its structure. It is concluded that these products are promising for the development of effective antimicrobial alternatives. However, further studies are needed to confirm its use, highlighting the need for in vivo tests.