SIMULTANEOUS ENZYMATIC-SYNTHESIS OF GLUCONIC ACID AND SORBITOL - CONTINUOUS PROCESS-DEVELOPMENT USING GLUCOSE-FRUCTOSE OXIDOREDUCTASE FROM ZYMOMONAS-MOBILIS
M. Silvamartinez et al., SIMULTANEOUS ENZYMATIC-SYNTHESIS OF GLUCONIC ACID AND SORBITOL - CONTINUOUS PROCESS-DEVELOPMENT USING GLUCOSE-FRUCTOSE OXIDOREDUCTASE FROM ZYMOMONAS-MOBILIS, Applied biochemistry and biotechnology, 70-2, 1998, pp. 863-868
The production of sorbitol and gluconic acid by isolated glucose-fruct
ose oxidoreductase (GFOR) from Zymomonas mobilis has been studied in a
convective, 100-mL loop reactor with tangential ultrafiltration Using
a dilution rate of 0.04/h and 5 kU/L GFOR, substrate conversion (3 M
sugar) in a single stage was >85%, and productivities of 126 g sorbito
l/(L.d) were obtained. At a constant recycle rate (3/min) and a membra
ne area of 50 cm(2), the dilution rates land thus productivities) were
however limited by a more than 30-fold reduction of the permeate flow
in the presence of high sugar and protein concentrations (5 g/L). Pro
tein was added, together with 10 mM dithiothreitol, to improve the sta
bility of GFOR during substrate turnover and crossflow filtration, thu
s leading to a stable operation of the enzyme reactor for at least 5 d
.