-Glucuronidase (EC 3.2.1.139) of family GH 115 from Scheffersomyces stipitis is a valuable enzyme for
the modification of water-soluble xylan into insoluble biopolymers, due to its unique ability to act on
polymeric xylans. The influence of growth rate on the production of -glucuronidase by recombinant
Saccharomyces cerevisiae MH1000pbk10D-glu in glucose-limited fed-batch culture was studied at 14 and
100 L scale. At and below the critical specific growth rate (crit) of 0.12 h−1 at 14 L scale, the biomass
yield coefficient (Yx/s) remained constant at 0.4 g g−1 with no ethanol production, whereas ethanol yields
relative to biomass (keth/x) of up to 0.54 g g−1 and a steady decrease in Yx/s were observed at > 0.12 h−1 .
Production of -glucuronidase was growth associated at a product yield (k˛-glu/x) of 0.45 mg g−1 , with
the highest biomass (37.35 g/L) and -glucuronidase (14.03 mg/L) concentrations, were recorded during
fed-batch culture at or near to crit. Scale-up with constant kLa from 14 to 100 L resulted in ethanol
concentrations of up to 2.5 g/L at = 0.12 h−1 . At this scale, -glucuronidase yield could be maximised at
growth rates below crit, to prevent localised high glucose concentration pockets at the feed entry zone
that would induce oxido-reductive metabolism. This is the first report where recombinant production of
-glucuronidase (EC 3.2.1.139) by S. cerevisiae was optimised for application at pilot scale.