In-line and selective phase separation of medium-chain carboxylic acids using membrane electrolysis.

We had extracted n-caproate from bioreactor broth. Here, we introduced in-line membrane electrolysis that utilized a pH gradient between two chambers to transfer the product into undissociated n-caproic acid without chemical addition. Due to the low maximum solubility of this acid, selective phase separation occurred, allowing simple product separation into an oily liquid containing ∼90% n-caproic and n-caprylic acid.