24 research outputs found
Yarrowia lipolytica growth under increased air pressure: influence on enzymes production
Improvement of microbial cell cultures oxygenation can be achieved by the
increase of total air pressure, which increases oxygen solubility in the medium. In this
work, a pressurized bioreactor was used for Yarrowia lipolytica batch cultivation under
increased air pressure from 1 to 6 bar. Cell growth was strongly enhanced by the pressure
rise. Fivefold and 3.4-fold increases in the biomass production and in specific growth rate,
respectively, were observed under 6 bar. The increase of oxygen availability caused the
induction of the antioxidant enzyme superoxide dismutase, which indicates that the
defensive mechanisms of the cells against oxidative stress were effective and cells could
cope with increased pressure. The pregrowth of Y. lipolytica under increased pressure
conditions did not affect the lipase production ability of the cells. Moreover, the
extracellular lipase activity increased 96% using a 5-bar air pressure instead of air at 1-
bar pressure during the enzyme production phase. Thus, air pressure increase in bioreactors
is an effective mean of cell mass and enzyme productivity enhancement in bioprocess based
in Y. lipolytica cultures