D. Poncelet et al., MICROENCAPSULATION OF SILICONE OILS WITHIN POLYAMIDE POLYETHYLENIMINEMEMBRANES AS OXYGEN CARRIERS FOR BIOREACTOR OXYGENATION, Journal of chemical technology and biotechnology, 57(3), 1993, pp. 253-263
Silicone oils were microencapsulated within polyamide (nylon) membrane
s cross-linked with polyethylenimine. Solubility of oxygen within the
silicones, whether encapsulated or not, was approximately 6 mmol dm-3,
representing solubilities approximately 20-fold higher than that of o
xygen in water. The response time of oxygen transfer from the microenc
apsulated oxygen carrier was less than 2.5 s; a more precise measureme
nt was limited by the response time characteristics of the oxygen prob
e. Assuming that the bioreactor volume consists of 10-20 % (v/v) micro
encapsulated silicone oil, this represents an enhancement of the oxyge
n reservoir by a factor ranging from 4 to 7 and improvement in oxygen
transfer rates greater than 15-fold due to the greatly increased speci
fic surface area in comparison to conventional bubble aeration. Circul
ation of oxygenated silicone oils encapsulated within inert polymeric
membranes may provide an efficient alternative to bioreactor oxygenati
on with shear sensitive cell systems, or in fermentations with high ox
ygen requirements.