Factorial designs: an efficient approach to choosing the main factors influencing growth and hydrolase production by Tetrahymena thermophila

Abstract

A fractional factorial design with eight trials was applied to select and model the effects of major factors, individually and in combination, on improving Tetrahymena thermophila growth and enzyme production. Regulated pH at 6.8 and olive oil at 0.5% (v/v) showed positive effects on fermentation, and increased cell growth parameters including generation time and maximal population formation. Lipase and protease production were also improved by these factors and were favoured by cultivation of Tetrahymena in darkness. This statistical experiment offers a beneficial and rapid screening procedure to select the most effective combination of factors influencing fermentation processes.

Tetrahymena in the Laboratory: Strain Resources, Methods for Culture, Maintenance, and Storage

“…In a bioreactor under conditions of high cell density fermentation and cell retention, skim milk based medium has supported the culture of Tetrahymena at cell densities of more than 2.2 × 10 7 cells/ml, equivalent to 48 g dry weight (Weide et al, 2006). A more dilute skim milk based medium (MYE medium, 1%(w/v) skim milk, 1%(w/v) yeast extract) has also been successfully used in batch fermenters to support growth up to ~3 × 10 6 cells/ml (De Coninck et al, 2004). …”

“…0.001% (v/v) Sigma AntiFoam 204, A6426) should be added to the culture to minimize cell damage. Since aeration stimulates growth and maximizes final cell concentration, but excessive agitation can cause cell damage, overall conditions for each large scale culture unit must be optimized individually (De Coninck et al, 2004). …”

“…However, conditions for growing Tetrahymena in fermenters or bioreactors can vary considerably depending on instrument type and experimental design, and optimal settings need to be worked out specifically for each large scale set-up (De Coninck et al, 2004). …”

“…Secretion of functional human enzymes by tetrahymena thermophila. BMC Biotechnol, 6 , 19. j De Coninck, J., Leclercq, B., Exbrayat, J. M., and Duyme, F. (2004). Factorial designs: An efficient approach to choosing the main factors influencing growth and hydrolase production by tetrahymena thermophila.…”

Bio-statistical enhancement of acyl transfer activity of amidase for biotransformation of <i>N</i>-substituted aromatic amides

“…This organism was thus mesophilic in its requirement of temperature for the growth and production of ATA. In order to evaluate the cumulative effect of different operational variables and their respective influence on the response, it is very important to use an experimental design that could account for these interactions (Bhatia et al, 2013b;De Coninck et al, 2004;Xiao et al, 2007). Therefore, the optimization of culture conditions was carried out using response surface methodology (RSM), which resulted in a 25% increase in the production of the ATA of amidase.…”