The application of auxiliary phases in fermentation technology has been demonstrated for many years. The roles of auxiliary phases in integrated bioreactor designs can be versatile, and include providing protection of the biocatalyst from inhibitory substrate or metabolite concentrations as well as separation of products in situ. These functions can afford enhanced productivity, simplified product recovery and purification, and lower overall energy expenditures. In the past, considerable attention has been focused on the use of immiscible organic liquids as recovery phases, resulting in the development of a full compliment of strategies and tools useful for such designs. Alternatively, the use of solid polymer resins as recovery phases has been explored, albeit to a significantly lesser extent. As such, equivalent algorithms have yet to be developed for these designs. Here we explore the potential use of polymeric resin as in situ product recovery (ISPR) devices as applied to n-butanol fermentation by Clostridium acetobutylicum ATCC 824. We provide considerable focus on the characterization of resin materials to better understand how their composition influences performance in the present study, as well as how polymer chemistry and bulk properties can be tuned to produce ideal materials for future applications. We have demonstrated that our ISPR design can dramatically improve n-butanol production while simplifying product purification protocols and drastically reducing recovery costs.