[Variability of plasmid profiles and properties of lactococcus in the process of cultivation and storage under different conditions]
2007
Krotovich, A.E. | Belyasova, N.A. | Masilevich, A.A.,Belarus State Technological Univ., Minsk (Belarus)
Research results of phenotypic and genetic variability of six starter cultures of Lactococcus lactis ssp. lactis in the process of their storage and cultivation were presented. It was shown that in the certain conditions of lactococcus storage and cultivation they demonstrate very high degree of morphological, biochemical and genetic variability. It was presumed that the observed variability could serve as the adaptive response to stress conditions. Development of morphological and biochemical bacterial segregates accumulated in Lactococcus lactis took place because of the rearrangement of cell-specific genes. Research results showed that cryoscopy in milk with cryoprotector as well as in glycerin proved to be the most effective methods of lactococcus storage which lowered the metabolism rate. Lactococcus lactis bacteria responded to the stress impact by various ways: change of morphological features, physiological or biochemical characteristics. Lactococcus lactis cultures differed in stability of features inheritance and genetic determinants. Some cultures possessed high variability and were hardly applicable for production processes; the other cultures inherited the features more steadfastly even in the storage conditions by subculturing method. Research results proved that in the conditions of industrial production it would be advisable to realize the process of lactococcus cultures preparation to the fermentation processes after lactococcus plansifter in the solid medium and realization of clone selection according to industrially valuable indices
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Эту запись предоставил National Academy of Sciences of Belarus