Abstract
A novel fed-batch approach for the production of L-phenylalanine (L-Phe)
with recombinant E. coli is presented concerning the on-line control of
the key fermentation parameters glucose and tyrosine. Two different
production strains possessing either the tyrosine feedback resistant
aroF(fbr) (encoding tyrosine feedback resistant DAHP-synthase
(3-desoxy-D-arabinoheptusonate-7-phosphate)) or the wild-type aroF(wt)
were used as model systems to elucidate the necessity of finding an
individual process optimum for each genotype. With the aid of tyrosine
control, wild-type aroF(wt) could be used for L-Phe production achieving
higher final L-Phe titers (34 g/L) than the aroF(fbr) strain (28 g/L)
and providing higher DAHP-synthase activities. With on-line glucose
control, an optimum glucose concentration of 5 g/L could be identified
that allowed a sufficient carbon supply for L-Phe production while at
the same time an overflow metabolism leading to acetate by-product
formation was avoided. The process approach is suitable for other
production strains not only in lab-scale but also in pilot-scale
bioreactors. (C) 2002 Wiley Periodicals, Inc.
Users
Please
log in to take part in the discussion (add own reviews or comments).
