Jm. Obon et al., L(-)-CARNITINE PRODUCTION WITH IMMOBILIZED ESCHERICHIA-COLI-CELLS IN CONTINUOUS REACTORS, Enzyme and microbial technology, 21(7), 1997, pp. 531-536
Escherichia coli 044 K74 was able to biotransform trans-crotonobetaine
to L(-)-carnitine in continuous packed-bed reactors with cells immobi
lized in glass beads or polyurethane foams. Fumarate was added to the
medium used for growth to increase both the carnitine production rate
and carnitine yield. Although high productivities close to 2 g l(-1)h(
-1) were obtained with both supports carnitine yields of 26% are still
low for its large-scale application. Biotransformation rates with imm
obilized resting cells took place to the same extent as that with grow
ing cells, but enhanced the carnitine yield; however after a week of c
ontinuous L(-)-carnitine production the biotransformation capacities d
iminished due to a progressive cell washout. The reactors with immobil
ized resting cells completely recovered the L(-)-carnitine production
rate after feeding the systems with complex medium for 12 h. Continuou
s reactors with immobilized resting cells look promising for bioconver
sions when run under continuous production/regeneration cycles. (C) 19
97 Elsevier Science Inc.