Downstream processing in the biochemical production of butanol, ethanol and acetone has predominately been implemented with conventional separation methods, such as various types of distillation and extraction. By means of the exceedingly efficient approach to process synthesis based on process graphs (P-graphs), the current work explores the merit of retrofitting the system for downstream processing by incorporating adsorption. It has given rise to a novel paradigm to efficiently plan for optimal retrofitting through the resynthesis of processing system in general and downstream processing system in biochemical production in particular.