Extractive fermentation

Simultaneous extraction of fermentation products during the fermentation process itself. Extraction commonly employs organic solvents, and the integrated process frequently raises yields because it removes the problem of product inhibition, where accumulating product slows the microorganisms. The technique suits products that inhibit their own synthesis, such as organic acids and biofuels, improving productivity and simplifying recovery. Butanol and ethanol fermentations benefit most, since these solvents become toxic to the producing clostridia and yeasts at modest concentrations. Membrane-based pervaporation and adsorption on resins offer gentler alternatives to liquid solvents, avoiding emulsion and toxicity problems while continuously pulling product from the broth.