Method for producing L-carnitine from crotonobetaine using a two stage continuous cell-recycle reactor

摘要

L(-)-carnitine is synthesized from crotonobetaine, crotonobetaine salts or derivatives in an ecologically advantageous manner by immobilizing cells of Escherichia coli 044 K74 on ceramics, glass beads or polyurethane disks in a two stage continuously operating cell recycle reactor containing a reaction medium. The medium preferably contains between 25 mM and 1 M crotonobetaine and at least 50 mM fumarate. Growing or resting cells of E. coli are retained in the reactor by micro or ultrafiltration membranes which are arranged as a flat membrane module or hollow fiber module. A first stage contains a reactor tank and a second stage contains an external recirculation loop connected to the tank for feeding the reaction medium through a filter unit. L-carnitine is synthesized under anaerobic conditions to produce a reaction medium containing L-carnitine and unreacted crotonobetaine. The reaction medium is transferred through the recirculation loop to the filter unit to produce a filtrate containing L-carnitine and a residue containing unreacted crotonobetaine and cells. The residue is recirculated to the reactor tank.