FOAM BEHAVIOR OF BIOLOGICAL MEDIA .4. HANSENULA-POLYMORPHA CULTIVATION FOAMS

The surface tension σ and foaminess Σ of (a) unlimited, (b) substrate limited, and (c) oxygen transfer limited growth media of Hansenula polymorpha were measured using methanol, ethanol or glucose as a substrate. The time dependence of σ can be described by the Avrami-Überreiter relationship: log (2.3 log V)=n log t+log b, where V = (σO - σeq/(σt - σeq, and σO, σt and σeq are σ at tM=0, tM=t and tM→∞ (equilibrium value). The constants n and b are functions of the fermentation time tF as long as the growth is unlimited but they are constant in the state of limited growth. With glucose substrate, the foaminess Σ can be presented as a definite function of the time, tDG, which is necessary to attain σeq. With alcohol as a substrate no definite Σ (tDG) function was found. © 1979 Springer-Verlag.