Controlled limited aeration and metabolic regulation during the production of ethanol from d xylose by pichia stipitis
Dellweg, H.; Rizzi, M.; Klein, C.
Journal of Biotechnology 12(2): 111-122
ISSN/ISBN: 0168-1656 DOI: 10.1016/0168-1656(89)90010-2
Under aerobic conditions Pichia stipitis CBS 5773 can grow on D-xylose with reduced specific growth rate, compared to D-glucose, but with comparable yield. In the absence of oxygen xylose is converted to ethanol and xylitol. Under conditions of controlled limited respiration ethanol production is increased whereas no xylitol is formed. With the aim of maximizing ethanol formation batch processes were performed with constant oxygen transfer rates by means of computer controlled stirrer speed. At a volumetric oxygen uptake rate (OUR) of 3.75 mmol l-1 h-1 the highest ethanol production production rate was found to be 0.12 g ethanol per g cell mass and hour at a product yield, Y of 0.39.