Potentially probiotic acetic acid bacteria isolation and identification from traditional dairies microbiota

Abstract

Among probiotics, acetic acid bacteria (AAB) can be used as preservative agents because of their high fermentation and acidification activities. This study aimed to isolate, identify and biologically characterise Acetobacter strains from traditional Iranian dairy products. Acetobacter strains were identified by catalase assay, Gram staining, and combined repetitive sequence-based PCR [(GTG)(5)-PCR fingerprints] and 16S rDNA gene sequencing. We identified eight strains belonging to four species, including Acetobacter aceti, Acetobacter indonesiensis, Acetobacter cibinongensis and Acetobacter syzygii. The molecular techniques could be used as an effective and rapid alternative tool to identify and characterise dairy-associated AAB. Primary probiotic assessments, including low pH and high bile salt tolerance tests, antagonistic activity test against pathogens, and antibiotic susceptibility confirmed the probiotic properties of these AAB, particularly A.cibinongensis 34L strain, which was isolated from curd. Therefore, this strain can be introduced as novel candidate probiotics that could be used in the food industry.