EXPERIMENTAL APPROACH TO THE INDUCTION OF NONCULTURABLE STATE OF LACTOCOCCUS LACTIS - Biochemistry and Biotechnology: Research and Development - page 45

Chapter 7
E XPERIMENTAL A PPROACH TO THE I NDUCTION OF
N ONCULTURABLE S TATE OF L ACTOCOCCUS L ACTIS
Yu. D. Pakhomov, 1, * S. K. Belus, 1 L. P. Blinkova, 1
L. G. Stoyanova 2 and E. A. Ustyugova 2
1 Mechnikov Research Institute of Vaccines and Sera RAMS. Moscow, Russia
2 Lomonosov Moscow State University, Biological Faculty,
Department of Microbiology. Moscow, Russia
A BSTRACT
Long-term exposure of microbial populations to physical, chemical and biological
stresses and their combinations causes formation of viable but nonculturable (VBNC)
cells. Detection of VBNC in the environment, food, and living organisms is a problem of
high medical and biological significance.
We have studied 3 bacteriocin producing strains of Lactococcus lactis ssp. lactis
(194, 729 and MGU). Obtained data show that the examined strains are capable of entry
into VBNC state within 2 weeks under carbohydrate starvation stress. However, synthesis
of antimicrobial compounds (bacteriocins) remained unaltered.
Keywords: Nonculturable, Lactococcus lactis, VBNC, carbohydrate starvation
I NTRODUCTION
Long-term exposure of microbial populations to physical, chemical biological stresses
and their combinations causes formation of viable but nonculturable (VBNC) cells. These
cells lose the ability to reproduce and slow down their metabolism to ensure survival of the
population through the stress period. VBNC state is known for a wide variety of
microorganisms. These include members of Escherichia , Vibrio , Klebsiella , Salmonella ,
Shigella , Legionella , Pseudomonas , Lactococcus and many other genera (Byrd J.J. et al.,