ABSTRACT
The separation of products from other bioreactor constituents is often a difficult and costly step in large-scale industrial bioprocesses. Particularly when products or by-products have an inhibitory effect on the production rate, their continuous selective removal generally leads to significantly increased conversion rates and improved overall process economics. A selective removal of ethanol from the fermentor and its simultaneous concentration can be achieved by a membrane process referred to as pervaporation. This chapter describes the fundamentals of this process and its application in ethanol recovery using a composite hollow-fiber membrane and illustrates its economics in a brief cost analysis. Pervaporation is a membrane separation process that combines the separation of volatile components from a liquid mixture by evaporation and permeation. In addition to pervaporation there are other membrane processes, such as micro-filtration or membrane distillation, that can be utilized in a continuous fermentation of ethanol.
