Interest in the physiology of lactic acid bacteria has been
stimulated by the industrial importance of these bacteria and
the potential use of genetic engineering in strain optimization.
For metabolic investigations, a defined growth medium
for these bacteria is desirable which (i) supports growth at a
reasonably high rate and (ii) allows for exponential growth
over a wide range of cell concentrations. Lactococcus lactis
has numerous growth requirements (8, 10, 13), which complicates
the formulation of a suitable growth medium for
these bacteria. The complex media MRS (5) and M17 (14) are
extensively used but are often unsuitable for physiological
studies, e.g., when a well-defined growth medium is required.
Presently many investigators use a defined growth
medium described by Otto et al. (11) and modified by
Poolman and Konings (12) which supports the growth of L.
lactis at reasonably high specific growth rates. Yet, this
medium contains virtually all building blocks for biosynthesis
of macromolecules, which complicates the study of
metabolic pathways. Here we show that a combination of
eight building blocks, all of which are amino acids, is
sufficient for growth of derivatives of L. lactis subsp. lactis
NCDO 712.