Prospecting of Antimicrobials for the Control of Leuconostoc mesenteroides and Lactobacillus fermentum

Considering that the ethanol production industry constantly faces bacterial contamination in its fermentative process, especially by gram-positive lactic acid bacteria, the objective of this study was to evaluate 12 compounds from the oxadiazole class and 12 compounds from the hydrazone class against these microorganisms. The compounds were obtained from a partner university and prepared on antibiogram disks at concentrations of 1 and 3 mg/mL, using dimethyl sulfoxide (DMSO). The bacteria used were of the genus Leuconostoc mesenteroides and Lactobacillus fermentum, acquired from national collections in lyophilized form and replicated in BHI culture medium. Subsequently, the bacteria were inoculated onto Petri dishes containing Mueller–Hinton agar using the streak method, followed by the addition of diffusion disks containing the antimicrobials. Ampicillin and actidione were used as positive control treatments, while disks soaked in DMSO served as negative controls. All treatments were performed in four replicates. It was concluded that the tested compounds from the hydrazone and oxadiazole classes do not exhibit antimicrobial activity at the evaluated concentrations against L. mesenteroides and L. fermentum bacteria.