A. Fang et al., UNEXPECTED ENHANCEMENT OF BETA-LACTAM ANTIBIOTIC FORMATION IN STREPTOMYCES-CLAVULIGERUS BY VERY HIGH-CONCENTRATIONS OF EXOGENOUS LYSINE, Applied microbiology and biotechnology, 44(6), 1996, pp. 705-709
L-Lysine is known to stimulate production of beta-lactam antibiotics b
y Streptomyces clavuligerus via provision of the lysine breakdown prod
uct, L-alpha-aminoadipic acid, which is a limiting precursor. Previous
investigations utilized levels of 10-20 mM L-lysine as an addition to
chemically-defined media resulting in 50-100% improvement in antibiot
ic production. We were surprised to note that as the concentration was
further increased, the organism responded by producing even higher ti
ters of antibiotics. The optimum concentration of 100 mM L-lysine yiel
ded an approximate 500% increase in production with only minor effects
on growth. DL- and D-Lysine also exerted enhancements suggesting the
presence of a lysine racemase or some other route from D-lysine to L-a
lpha-aminoadipate in this organism; D-lysine was considerably less pot
ent than DL- or L-lysine.