Fed-batch production of a soluble beta-1,4-galactosyltransferase with Saccharomyces cerevisiae

A feedback-controlled fed-batch process for the recombinant production of a soluble human beta-1,4-galactosyltransferase (NdrGal-T) with Saccharomyces cerevisiae was developed and scaled up to the pilot scale. A 5000 U NdrGal -T fermentation run was performed on a 300 l scale. Indirect feedback contr ol of the glucose feeding with RQ data at a set-point of RQ = 1.1 resulted in higher NdrGal-T activities (30 U/l) than direct feedback control of gluc ose with on-line flow-injection analysis (9 U/l). This increase in final ac tivity of NdrGal-T by a factor of 42 compared to published data makes the f ed-batch production of glycosyltransferases with a Saccharomyces cerevisiae expression system competitive with cell-culture systems. (C) 1999 Elsevier Science Inc. All rights reserved.