Substrate Cage™ products are research tools for the life sciences designed to facilitate the development of bioconversion processes using insoluble polymeric materials. Insoluble polymers including plant cellulosic, crustacean shell, man-made plastics, and other polymeric waste materials are potentially valuable sources of carbon-based chemicals. Recent advances in the use of biological systems to convert cellulose feedstocks into biofuels have allowed an otherwise unusable material to become commercially important. Similar bioconversion processes for municipal waste disposal are being commercially implemented. These advances are making it increasingly clear that polymeric materials, traditionally discarded as waste, can now be used to recover commercially valuable products.

Many of the potentially useful polymeric materials are insoluble in aqueous solutions. However, most bioconversion processes, which ultimately rely on enzymes produced by microbes to catalyze the chemical transformations, are performed in aqueous conditions. Thus, there is an inherent incompatibility between the polymer material (the substrate) and the reaction conditions. This incompatibility encumbers the methods used to experimentally measure the conversion of the polymeric substrate into derivative chemicals (the products) thereby increasing the costs and slowing the progress of developing commercially viable processes. In effect, the presence of the insoluble material in the reaction mixture interferes with the ability to measure the products formed. The Substrate Cage™ is designed to eliminate this impediment by containing the insoluble material in a small containment device that allows for the free flow of microbes or enzymes into and out of the cage, and thus access to the substrate but retains the insoluble material so that it does not interfere with the subsequent measurement of the bioconversion processes.