Growth Kinetics of Saccharomyces cerevisiae and Tape Yeast on the Cassava Pulp Fermentation and Its Granular Morphology Changes

Saccharomyces cerevisiae is the most commonly used yeast in the fermentation process on high starch/carbohydrate substrates, for example, cassava pulp, a by-product from the tapioca industry. In addition to the pure culture of S. cerevisiae, the fermentation process of cassava pulp can be done using tape yeast (a consortium of yeast, fungal and bacteria). The objective of this research was to study the growth kinetics of S. cerevisiae and tape yeast on cassava pulp fermentation and its granular morphology changes. The growth kinetics of Saccharomyces cerevisiae and tape yeast was observed through cells number, rate of starch degradation, rate of dietary fiber degradation, rate of cyanide degradation, and rate of protein formation; the granular morphology analysis was conducted with the scanning electron microscope (SEM). The research showed that the S. cerevisiae pure culture could grow better during cassava pulp fermentation compared to tape yeast, which is reflected by the logarithmic growth rate (up to 72 h versus 48 h) and causes changes in granular morphology. The difference in the growth rate between S. cerevisiae pure culture and tape yeast will cause a difference in starch degradation rate (73.02 mg/h versus 65.09 mg/h), dietary fiber degradation rate (87.33 mg/h versus 21.09 mg/h), cyanide degradation rate (92.57.10-2 ppm/h versus 97.49.10-2 ppm/h), protein formation rate (48.92 mg/h versus 50.08 mg/h).