The disclosure is directed to a method for recovering products from a fermentation broth. The disclosure relates to the use of dehydration to recover products which have close boiling points, such as ethanol and isopropanol, from a fermentation broth. In an embodiment, the recovery of product is completed in a manner that minimizes stress on the microbial biomass present in the fermentation broth, such that it remains viable, at least in part, and may be recycled and reused in the fermentation process, which may result in increased efficiency in the fermentation process. The dehydration reactor may be used downstream of a distillation vessel and converts products such as ethanol and isopropanol into ethylene and propylene. The ethylene and propylene can be used to prepare a component of a fuel or can be polymerized. To minimize stress on the microbial biomass the distillation vessel may be under vacuum.