text: The fermentation processes used in alcohol production is commonly maintained in low oxygen conditions, under a blanket of carbon dioxide, while growing yeast for biomass involves aerating the broth for maximized energy production. Despite the bactericidal effects of ethanol, acidifying effects of fermentation, and low oxygen conditions of industrial alcohol production, bacteria that undergo lactic acid fermentation can contaminate such facilities because lactic acid has a low pKa of 3.86 to avoid decoupling the pH membrane gradient that supports regulated transport.