Growth-Kinetics of Top and Bottom Cultures of Saccharomyces Spp in A Chemostat Using Sugarbeet Molasses

AbstractGrowth kinetics were evaluated for three yeast strains of the genus Saccharomyces. Two topfloating strains, SF 115 and SF 116 and one flocculant yeast SF 104 were analyzed in pure and mixed cultures in 1‐liter continuous fermentation experiments in a chemostat. Growth was monitored for 72 h at 30°C in a medium containing sugarbeet molasses and 1.0 g/liter each of NH4H2PO4 and urea. SF 115 and SF 116 were found to have lower μmax values of 0.290 and 0.296 h−1, respectively, than SF 104, which had a μmax of 0.364 h−1. The two top‐floating yeasts (SF 115 and SF 116) demonstrated greater affinity for the substrate and utilized substrates at a greater rate. They have K8 values of 4.03 × 10−3 M and 3.798 × 10−3 M, respectively, compared to 9.06 × 10−3 M for SF 104. A mixed culture of SF 116 and SF and SF 104 was found to have a μmax of 0.426 h−1 with a Ks of 6.924 × 10−3 M. SF 115 grown in mixed culture with SF 104 exhibited a μmax of 0.473 h−1 with a Ks of 7.975 × 10−3 M. In both cases, the SF 104 was the dominant microbe in mixed culture systems.