title: Yarrowia lipolytica growth under increased air pressure: influence on enzyme production.
abstract: 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.
authors.affiliation: IBB-Institute for Biotechnology and Bioengineering, Centre for Biological Engineering, Universidade do Minho, Campus de Gualtar, Braga, Portugal.
authors.forename: Marlene
authors.initials: M
authors.lastname: Lopes
authors.forename: Nelma
authors.initials: N
authors.lastname: Gomes
authors.forename: Manuel
authors.initials: M
authors.lastname: Mota
authors.forename: Isabel
authors.initials: I
authors.lastname: Belo
mesh_terms: D019149:Bioreactors / Q000382:microbiology*; D018929:Cell Culture Techniques / Q000379:methods; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D015966:Gene Expression Regulation, Fungal / Q000502:physiology*; D008049:Lipase / Q000378:metabolism*; D011312:Pressure; D013482:Superoxide Dismutase / Q000378:metabolism*; D025062:Yarrowia / Q000201:enzymology* / Q000254:growth & development*
chemical_list: D013482:Superoxide Dismutase; D008049:Lipase