The production of extracellular inulinase (\-1,2-d-fructan fructanohydrolase, EC 188.8.131.52) was studied in fed-batch cultures of the yeast Kluyveromyces marxianus CBS 6556 at 30 and at 40° C. At both temperatures, the final biomass concentration exceeded 100 g·l-1 and more than 2 g enzyme. L-1 of culture supernatant was produced. The biomass yield on O2 at 40° C was substantially lower than at 30°C. Nevertheless, at 40° C a growth rate of 0.20 h-1 could be maintained for a longer period than at 30° C. The unexpected higher O2-transfer rate at 40°C is probably due to a lower viscosity of the culture broth. The 40°C fermentation took only 33 h as compared to 42 h at 30° C. These results indicate that K. marxianus is a promising host for the extracellular production of heterologous proteins under the control of the inulinase promoter.
ASJC Scopus subject areas
- Applied Microbiology and Biotechnology