Mixed culture cultivations

In many cases, microbial life in nature develops into zones within which communities are dominated by one or a few functional groups, such as aerobes, sulfate reducers, or methanogens. Distinct zoning is characteristic, for example, of microbial mats (Konhauser, 2007), hot springs (Fouke et al., 2003), marine sediments and freshwater muds (Berner, 1980), contaminated aquifers (Bekins et al., 1999), and pristine groundwater flows (Chapelle and Lovley, 1992). Communities develop as well in laboratory experiments, when microbes are cultivated in pure or mixed culture. 

Figure 7.14. Biogenic decomposition and/or incorporation of MeHg by incubation experiments with mixed algae and bacterial cultures from the North Sea (MeHg" and a mixed culture of cultivated algae and bacteria were added to ocean water samples) (47).

Mathys S, Meile L, Lacroix C. Co-cultivation of a bacteriocin-producing mixed culture of Bifidobacterium thermophilum RBL67 and Pediococcus acidilactici UVAl isolated from baby faeces. / Appl Microbiol. 2009 107(1) 36—46. 

If lactose-fermenting P. shermanii is used, cheese whey can be used as a substrate. From the whey containing 12% of dry substances, only 50% of lactose is utilized by P. shermanii, producing 1.6-2.2% solution of propionic acid (Bodie et al., 1987). In the combined batch culture, composed of P. shermanii and Lactobacillus casei, lactose is completely utilized and a 3% solution of propionic acid is produced in 52 h. When the medium is partially replaced during cultivation, a 4.5% solution of propionic acid is obtained by raising the concentration of dry substances in the whey up to 18% the production is increased up to 6.5% in mixed culture. For industrial production it is advisable to add a reducing agent to the medium (see above. Chapter 3), then the ratio of propionic to acetic acid will be increased (Emde and Schink, 1990). 

As a leaven for bread a mixed culture of Lactobacillus brevis TKK 105-6-1 and P. acidipropionici TKK 114-3-1 was used after three days of combined cultivation at 30 C in the medium containing hydrolyzed wheat flour, yeast extract and mineral salts (Javanainen et al., 1987) the pH of the culture was adjusted to 5.0-5.8 by adding calcium carbonate (20 g/1). Almost... 

Plant tissue culture technique provides completely controlled conditions to elucidate the growth and physiology of the cells and to study host-parasite interactions at the cellular level. There exists probably single paper on this interesting technique in ergot research on cultivation of C. fusiformis on a Pennisetum typhoides cell culture. The authors (Roy and Kumar, 1985) established the methodology and studied nutritional demands of the mixed culture with respect to the growth and alkaloid production. 

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