Bacteria, lactic acid location

Lactic acid bacteria synthesise a range of different polysaccharides, defined by their location in the cell. Some are located intracellularly and are used as energy or carbon sources others are cell wall components and some are located outside the cell wall. The latter are called extracellular polysaccharides (EPs) and are either associated with the cell wall as a slime capsule, or secreted into the environment. Many lactic acid bacteria such as Lactobacillus delbrueckii subsp. bulgaricus, Streptococcus thermo-philus and Lactococcus lactis subsp. cremoris produce EPs. 

Sometimes fermentors must be drawn off before the ideal tannin concentration has been attained. This operation is recommended for stuck fermentations (Section 3.8.1). For reasons already mentioned (Section 3.8.3), these is the risk of development of lactic acid bacteria in sugar-containing musts with inactive yeasts. The volatile acidity would consequently increase dramatically. Drawing off the juice is a means of eliminating the majority of the bacterial population located in the pomace. Sulfiting can be effected at the same time (3 g/hl). This operation may, of course, delay mal-olactic fermentation, but the sulfur dioxide concentration should be calculated to allow the alcoholic fermentation to restart while blocking bacterial activity. 

Mitochondria and unicellular organisms. Bacteria have no mitochondria. Being of mitochondrial size, the bacterium has to function as its own mitochondrion its plasma membrane, although it lacks aristae, has to attempt to carry out as many as it can of the complex activities of eukaryotic mitochondria. Hence many of the typical enzymes of eukaryotic mitochondria are located in the bacterial plasma membrane (De Ley and Docky, i960 Mitchell and Moyle, 1956a). In particular, the enzymes of the tricarboxylic acid cycle are found there. More than 90% of the cell s succinic, malic, lactic, and formic dehydrogenases, as well as the cytochrome oxidase, are present in the plasma membrane of typical bacteria, e.g. Staphylococcus aureus and Micrococcus lysodeikticus (Mitchell, 1961,1963). 

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