When various autoclaved microbial
cells suspensions (exogenous elicitors) were
added to Catharanthus roseus cell cultures, its
growth was inhibited but 5¢-phosphodiesterase
(PDase) production was stimulated. The greatest
effect was with autoclaved Alteromonas macleodii:
the dry cell concentration decreased from 13
to 10.9 mg/ml while PDase production increased
from 0.022 to 0.235 U/ml. A combination of
A. macleodii (as exogenous elicitor) and 0.1%(w/
v) alginate oligomers (AO: acting as both
endogenous elicitor and scavenger of active oxygen
species) minimized the cell growth inhibition
but enhanced PDase production (0.474 U/ml)
about 20 times higher than the control (no addition).
The method for the preparation of mixed
alginate elicitors with high activities containing
exogenous elicitor (autoclaved A. macleodii),
endogenous elicitor (AO), and trans-4,5-dihydroxy-
2-cyclopenten-1-one was developed. The
mixed alginate elicitors significantly promoted
PDase production (2.67 U/ml) by C. roseus, and
the productivity was increased 120-fold compared
to the control without cell growth inhibition.