Evaluation of Rhodotorula growth on solid substrate via a linear mixed effects model
2011
Krulikovska, T.,Vysoka Skola Chemicko-technologicka, Prague (Czech Republic). Ustav Kvasne Chemie a Bioinzenyrstvi | Jarosova, E.,Skoda Auto Vysoka Skola, Mlada Boleslav (Czech Republic) | Patakova, P.,Vysoka Skola Chemicko-technologicka, Prague (Czech Republic). Ustav Kvasne Chemie a Bioinzenyrstvi
The growth of Rhodotorula glutinis and Rhodotorula mucilaginosa was studied under optimal and stress cultivation conditions at 10 deg C and 20 deg C for 14 days. The method of image analysis was used to determine the size of colonies. The linear mixed effects model implemented in the statistical program S-PLUS was applied to analyse the repeated measurements. Two-phase kinetics was confirmed and the mean growth rates in the second linear phase under various stress conditions were estimated. The results indicated a higher growth rate of R. mucilaginosa than was that of R. glutinis under all cultivation conditions. The highest growth rate was observed during the cultivation of R. mucilaginosa in media with 2% of NaCl at 20 deg C. The impact of neglecting the fact that repeated data are not independent and using the classical regression model instead of the mixed effects model was demonstrated through the comparison of the confidence intervals for the parameters based on both approaches. While the point estimates of the corresponding parameters were similar, the width of the confidence intervals differed substantially.
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