CHAPTER 8: Green Downstream Processing in the Production of Enzymes

Green chemistry is the key to sustainable development. The use of enzymes is undoubtedly an ideal choice toward “greening” chemical reactions. However, a real green catalyst is one produced by technologies that integrate reduced impact on the environment as a performance criterion for the design of all production steps, including the downstream ones. As enzyme concentration in fermentation broth is often very low, concentration methods are required, which include precipitation, and a more advanced method, ultrafiltration. Ultrafiltration operates under mild conditions, promoting lower denaturation, deactivation and/or degradation rates of highly labile products. In recent decades, new purification technologies, such as two-phase systems, membrane separation and immune purification, have been studied. Additionally, old methods, such as chromatographic techniques, have been reformulated for more integrated use. A radically different approach to overcome the limitations associated with packed bed chromatography is to use synthetic microporous or macroporous membranes as chromatographic media. As for two-phase systems, they are based on the partition principles of the proteins in a two-phase aqueous system. Extractive fermentation is an emerging technique that involves the use of aqueous two-phase system based in situ fermentation processes.