Study of the drop size frequencies in a microbial growth system with an aqueous-organic culture medium: Lipase production from Candida rugosa

The influence of the drop size of oleic acid on extracellular lipase production by Candida rugosa was studied. The specific interfacial area was determined under different experimental conditions and the drop populations obtained were compared on the basis of the Kruskal-Wallis statistical test. Lipase production was found to increase with increasing drop size of the disperse phase, i.e. when the microorganism grew at a low stirring rate (300 rpm). Enzyme production in two bioreactors of different volume, viz. Biostat E (5 1) and Bioflo III (1 1), was also compared. The two bioreactors were found to yield similar enzyme activities provided the same initial oleic acid drop size was used. This allows the establishment of a specific criterion for adaptation to a different scale or bioreactor, and for the mathematical modelling of the process.