The effects of fermentation conditions on yeast cell debris particle size distribution during high pressure homogenisation
Authors
 Received:
DOI: 10.1007/BF00369846
 Cite this article as:
 Siddiqi, S.F., Bulmer, M., Ayazi Shamlou, P. et al. Bioprocess Engineering (1995) 14: 1. doi:10.1007/BF00369846
Abstract
Experiments were performed to characterize the particle size distribution of bakers' yeast cells during high pressure homogenisation. Results were obtained for mechanically agitated batch and continuously grown cultures under a range of operating conditions. It was found that the dependency of cell debris size distribution on the number of passes through the homogeniser and the homogeniser pressure was independent of the cell properties and culture conditions, but for a fixed pressure and number of passes the extent of disruption was strongly affected by the operating conditions in the fermenter. The entire cell debris size distributions were successfully simulated using the mean and variance of the distributions and a previously published model equation which related these parameters to the operating pressure and number of passes through the homogeniser.
List of Symbols
 k

breakage coefficient in Eq. 1
 d

cell diameter
 d _{50}

median diameter of homogenate size distribution
 d _{50} ^{⋆}

dimensionless d _{50} defined as \(\frac{{d_{50_{N = 0} }  d_{50} }}{{d_{50_{N = 0} } }}\)
 D

dilution rate
 F(d _{NP})

cumulative undersize distribution (volume basis)
 N

number of passes
 P

total pressure
 P _{threshold}

threshold pressure
 ΔP

(PP _{threshold})
 w

Boltzmann parameter, Eq. 4
 w^{⋆}

dimensionless standard deviation defined as \(w^ \star = \frac{{w_{N = 0}  w}}{{w_{N = 0} }}\)
Greek Letters
 α

exponent in Eq. 1
 β

exponent in Eq. 1