Effects of aeration on growth and on production of bacteriocins and other metabolites in cultures of eight strains of lactic acid bacteria.

In general, it is accepted that the production of bacteriocins in lactic acid bacteria cultures implies moderately to highly restrictive conditions regarding the availability of oxygen. However, the situation appears to be more complex, probably owing to the facultative anaerobic character of these microorganisms. By studying the culture of eight strains of lactic acid bacteria carried out in vessels with different loads of medium within an interval that determines linearly the minimum availability of oxygen, the existence of three types of behavior was highlighted: production increases (1) with the availability of oxygen, (2) with the restriction of this availability, and (3) toward both extremes of these conditions, diminishing in intermediate situations. These behaviors affected not only the production of bacteriocins, but also their metabolic character (in the Luedeking and Piret sense), as well as the production of other characteristic metabolites, such as lactic acid, acetic acid, and ethanol.