Lactic acid bacteria cultivation media

Successful cultivation of microorganisms for growth and identification requires use of various types of media, either liquid (referred to as hroths) or solid by inclusion of agar. For winemakers, a growth medium may he as simple as diluted sterile grape juice for the activation and expansion of yeast starter cultures or as complicated as that necessary to grow lactic acid bacteria. 

One drawback in using small-porosity filters is premature plugging or clogging. Some suspensions used in media are hazy or cloudy (e.g., the liver extract used in media for the cultivation of lactic acid bacteria) and these can quickly clog a 0.45 pm membrane. In these cases, it may be necessary to prefilter through Whatman no.l filter paper or centrifuge the medium or ingredients to remove haziness or cloudiness prior to sterile filtration. 

The media outlined for the cultivation of lactic acid bacteria are the apple juice Rogosa medium (King and Beelman, 1986) and the tomato juice-glucose-fructose-malate medium (Izuagbe et al., 1985). These media use either apple juice or tomato juice serum to provide the so-called tomato juice factor (Section 2.3). Liver extract or concentrate has a number of vitamins that improves bacterial growth and is available from Sigma Chemical Company. Both media can be made selective against Sac-charomyces by the addition of cycloheximide. 

Gluconobacter growing on GYCM over time (3 to 5 weeks) produces water-soluble brown pigments, which are not seen in the case of any similarly cultivated Acetobacter species. Grown on this medium, Acetobacter will produce clear zones or halos around colonies because the acid being produced will neutralize the CaCOs. Unlike the lactic acid bacteria, acetic acid bacteria are obligate aerobes and so it is necessary to use spread plates. 

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