Evaluation of Growth Kinetics and Biomass Yield of Baker's Yeast on Potato Flour

Abstract

The study aims to evaluate the growth kinetics of two different Baker's yeast (S. cerevisiae) strains and to establish regression models for predicting and optimizing the growth conditions of the strains. Two yeast strains of S. cerevisiae: one was a Commercial Strain (CS) and another was isolated from traditional dry wine residue from the Madhupur region, Bangladesh (MS), were used in the study. The effects of four different factors, viz., time, temperature, agitation, and the concentration of potato powder were assessed. The performance of the growth of the strains was monitored using three responses, like OD at 600 nm, ethanol production, and biomass yield (g·L^-1). A fractional factorial design (2^4-1) was used to generate the experimental trials, as well as to analyze the data to design a geometrical representation. The highest value of optical density, ethanol, and biomass production for S. cerevisiae (CS) were 1.439, 6.56 (g·L^-1), and 0.39 (g·L^-1), respectively, and for S. cerevisiae (MS) were 0.645, 0.621 (g·L^-1), and 0.23 (g·L^-1), respectively. The best conditions for biomass production were at 1% potato powder concentration, a temperature of 30 °C, and agitation at 150 rpm. By using a regression model, it can be said that for two-factor interactions, potato powder concentration with time and time with agitation had the significant effects, but three-factor interactions had no significant effect on the experiment. By establishing regression models from the obtained data, prediction and optimization of the strains' growth conditions can be easily done.