lactobacillus acetotolerans lactobacillus acetotolerans lactobacillus acetotolerans (neo-latin 'vinegar-tolerating milk-bacillus') is a species of gram positive bacteria in the genus lactobacillus. discovered in rice wine vinegar, it has a very high tolerance for acetic acid. it can tolerate an acetic acid concentration of over 9% and a ph as low as 3.3. it is known to produce sour flavors in beer it invades, by producing lactic acid. lactobacillus acetotolerans scientific classification domain: bacteria phylum: bacillota class: bacilli order: lactobacillales family: lactobacillaceae genus: lactobacillus species: l. acetotolerans binomial name lactobacillus acetotoleransetsuzo entani, hiroshi masai and ken-ichiro suzuki, 1986