Propionibacterium spp

Lactose is readily fermented by lactic acid bacteria, especially Lactococcus spp. and Lactobacillus spp., to lactic acid, and by some species of yeast, e.g. Kluyveromyces spp., to ethanol (Figure 2.27). Lactic acid may be used as a food acidulant, as a component in the manufacture of plastics, or converted to ammonium lactate as a source of nitrogen for animal nutrition. It can be converted to propionic acid, which has many food applications, by Propionibacterium spp. Potable ethanol is being produced commercially from lactose in whey or UF permeate. The ethanol may also be used for industrial purposes or as a fuel but is probably not cost-competitive with ethanol produced by fermentation of sucrose or chemically. The ethanol may also be oxidized to acetic acid. The mother liquor remaining from the production of lactic acid or ethanol may be subjected to anaerobic digestion with the production of methane (CH4) for use as a fuel several such plants are in commercial use. 

Swiss-type cheeses are ripened at about 22°C for a period to encourage the growth of Propionibacterium spp. which use lactic acid as an energy... 

Fermentation of lactic acid to yield propionic acid, carbon dioxide, acetic acid, and succinic acid is important for proper eye formation and flavor development in Emmental, Gruyere, and Swiss-type cheese varieties. This fermentation is associated with Propionibacterium spp. subspecies of Propionibacterium freudenreichii are of greatest significance. These organisms can also be used for industrial production of vitamin Bi2 and propionic acid. 

During cheese production lactose is converted to lactic acid by starter lactic acid bacteria (LAB). Any unfermented lactose is converted to d- and L-lactate by nonstarter lactic acid bacteria (NSLAB) and racemization, respectively. Lactate can be oxidized by LAB in cheese to acetate, ethanol, formic acid, and carbon dioxide at a rate dependent on oxygen availability (McSweeney, 2004). Other pathways include conversion to propionate, acetate, water, and carbon dioxide by Propionibacterium spp. carbon dioxide and water by Penicillium spp. yeasts and butyric acid and hydrogen by Clostridium spp. The rate of lactose metabolism influences proteolysis and flavor formation (Creamer et al., 1985 Fox et al., 1990). 

Skin Staphylococcus spp. (e.g., S. epidermidis) Streptococcus spp. Corynebacterium spp. Propionibacterium spp. Enteric bacilli (some sites) Acinetobacter spp. (Coccobacilli) ... 

Cheeses Lactobacillus buchneri, L. bulgaricus, L. plantarum, L. easel, L. acidophilus, L. arabinosae. Streptococcus faecium, S. mitis. Bacillus macerans, Propionibacterium spp. Histamine, cadaverine, putrescine, tyramine, tryptamine... 

The lipase/esterase of Pediococcus spp. has received little attention. Tza-netakis and Litopoulou-Tzanetaki (1989) found only weak esterase and lipase activities in a number of strains of P. pentosaceus of dairy origin by means of the API-ZYM system. Bhowmik and Marth (1989) found esterase activity in six strains of P. pentosaceus but none in two strains of P. acidilac-ticL The lipases of Propionibacterium shermanii studied by Oterholm et al. (1970) were optimally active at pH 7.2 and 47°C on tributyrin the enzymes showed a high preference for tripropionate and tributyrin and were inhibited by Hg and Na2HAs04 but not by pCMB or EDTA. Some esterase activity was observed but the enzyme was more active on emulsified than on soluble substrates. 

Acne itself is a disorder of the pilosebaceous follicles and these follicles as well as the adjacent skin surface are well populated with micro-organisms. Three micro-organisms have been implicated in 2icnc - Propionibacterium acnes, Staphylococci spp. and Pityrosporum ovale-With the former being the most important. However, micrococci, sarcina and yeasts are also present and a change in their population may predispose the patient to acne (Holland and Cunliffe, 1979). 

Lactobacillus and Propionibacterium strains were evaluated by El-Nezami et al. (2002) regarding their ability to remove seven Fusarium toxins (trichothecenes) from solution. Results showed that L. rhamnosus GG and Propionibacterium freudenrei-chii spp. shermanii JS were able to bind 18-93% of the deoxynivalenol, diacetoxy-scirpenol, and fusarenon in solution, while L. rhamnosus LC-705 removed 10-64% of deoxynivalenol and diacetoxyscirpenol from liquid medium. When comparing the ability of lactic and propionic bacteria to remove toxin from solution, Niderkom, Boudra, and Morgavi (2006) found that deoxynivalenol and fumonisin removal was strain specific, and that in general propionic acid bacteria was less efficient than lactic acid bacteria. The best results were achieved with L. rhamnosus for ranoval of deoxynivalenol (55%), Leuconostoc mesenteroides for fumonisin Bi (about 82%), and L. lactis for fumonisin B2 (100%) (Niderkom et al., 2006). 

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