The ratio of the ingoing volume flow rate ()
and the culture volume (). In continuous fermentation, a measure of a rate at which the existing medium is replaced with fresh medium,
is the reciprocal of the hydraulic retention time
().
Source:
PAC, 1992, 64, 143
(Glossary for chemists of terms used in biotechnology (IUPAC Recommendations 1992))
on page 152
)
and the culture volume (
). In continuous fermentation, a measure of a rate at which the existing medium is replaced with fresh medium, 
is the reciprocal of the hydraulic retention time
(
).