The effect of n-dodecane addition on oxygen transfer in stirred bioreactors for Saccharomyces cerevisiae broths

Abstract

The previous works on simulated and P. shermanii broths were continued and developed for Saccharomyces cerevisiae broths. The obtained results indicated the considerable increase of k?a in the presence of n-dodecane as an oxygen-vector, but the magnitude of this effect had to be correlated with the biomass characteristics, especially with hydrophobicity. Due to the higher affinity of yeast cells for hydrocarbon droplets, increase of the oxygen mass transfer rate was lower than that recorded for simulated broths or bacterial suspensions.Prethodna istrazivanja, koja su se bavila simulacijom P. shermanii suspenzije nastavljena su i u ovom radu prime-njena na suspenziji Saccharomyces cerevisia. Dobijeni rezultati ukazuju da je moguce znacajno uvecanje zapreminskog koeficijenta prenosa mase k?a u prisustvu n-dodekana kao "kiseonicnog vektora", ali se intenzitet uvecanja mora korelisati sa karakteristikama biomase, posebno njenom hidrofobnoscu. Zbog velikog afiniteta celija kvasca ka kapima ugljovodonika, povecanje prenosa mase kiseonika je nesto manje nego sto je zabelezeno u slucaju simulacionih fermentacionih medijuma ili suspenzija bakterija.