Area and Volume Phase Ratio

The most common approach in organic-aqueous biphasic systems is to operate with a continuous aqueous phase, which prevents the occurrence of extreme pH spots, with a volume phase ratio up to 0.4 [35]. An adequate selection of the organic-aqueous volume phase ratio allows for high interfacial areas. The influence of the volume phase ratio in the interfacial area (a) can be predicted according to Equation 1. 

More detailed information on the values used for parameters termed z3 can be found elsewhere [40]. 

In systems used in biphasic biocatalysis, maximum interfacial area is observed for a volume fraction of the organic phase close to that observed for phase inversion, which occurs within a 0.4 to 0.7 range. Extreme values of the volume fraction of the organic phase, under 0.1 or over 0.9 should also be avoided, since phase separation is poor and makes product recovery difficult. 

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