In Situ Recovery of Products - In many cases, the fermentation products are inhibitory to the product formation. In all such cases, removal of the product during the fermentation process, i.e., in situ recovery of the products, greatly increases product yields.

A number of methods have been successfully used for this purpose, which can be grouped into the following three broad groups:

(i) vacuum,
(ii) two phase systems and
(iii) dialysis.