Chapter 7 Innovative separation methods in bioprocessing J. A. ASENJO, Biochemical Engineering Laboratory, Department of Food Science and CHAUDHURI, School of Chemical Engineering, University of Bath, Bath BA2 7AY UK 7.1 INTRODUCTION Discoveries and achievements in modern biology and recombinant dna technology in the last few years have resulted in the development of a number of new therapeutics for human use such as insulin, human growth hormone(hGH), tissue plasminogen activator (tPA)for cardiac disease, erythropoietin(EPO)and hepatitis B vaccine and thus the possibility of their industrial large-scale production. This poses a tremendous challenge for the chemical and biochemical engineer in terms of developing efficient separation processes for these new proteins. As they are intended for human use the levels of purity required are of the order of 99.9% or 99.98% or even higher(depending on dosage)and they have to be separated from a very large number of contaminants, other proteins nucleic acids, polysaccharides and many other components present in the cell culture or cell lysate used to manufacture these proteins. Competitive advantage in production depends not only on innovations in molecular biology and other areas of basic biological sciences but also on innovation and optimisation of separation and downstream proc esses The main issues important for the development of novel separation techniques to give mproved resolution, simplicity, speed, ease of scale-up and possibly continuou operation are presented and discussed. The assessment of the state of the art as well as promising future developments concentrate on the separation and purification of proteins from complex mixtures. The present trend to develop techniques that exploit fundamental physicochemical principles more efficiently is emphasised. This includes the analysis of the physicochemical properties of proteins such as pl, charge as a function of pH, biological affinity (including metal ion and dye affinity), hydrophobicity and size and itsChapter 7 Innovative separation methods in bioprocessing J. A. ASENJO, Biochemical Engineering Laboratory, Department of Food Science and Technology, The University of Reading, Reading RG6 6AP, UK and J. B. CHAUDHURI, School of Chemical Engineering, University of Bath, Bath BA2 7AY, UK 7.1 INTRODUCTION Discoveries and achievements in modern biology and recombinant DNA technology in the last few years have resulted in the development of a number of new therapeutics for human use such as insulin, human growth hormone (hGH), tissue plasminogen activator (tPA) for cardiac disease, erythropoietin (EPO) and hepatitis B vaccine and thus the possibility of their industrial large-scale production. This poses a tremendous challenge for the chemical and biochemical engineer in terms of developing efficient separation processes for these new proteins. As they are intended for human use the levels of purity required are of the order of 99.9% or 99.98% or even higher (depending on dosage) and they have to be separated from a very large number of contaminants, other proteins, nucleic acids, polysaccharides and many other components present in the cell culture or cell lysate used to manufacture these proteins. Competitive advantage in production depends not only on innovations in molecular biology and other areas of basic biological sciences but also on innovation and optimisation of separation and downstream proc￾esses. The main issues important for the development of novel separation techniques to give improved resolution, simplicity, speed, ease of scale-up and possibly continuous operation are presented and discussed. The assessment of the state of the art as well as promising future developments concentrate on the separation and purification of proteins from complex mixtures. The present trend to develop techniques that exploit fundamental physicochemical principles more efficiently is emphasised. This includes the analysis of the physicochemical properties of proteins such as PI, charge as a function of pH, biological affinity (including metal ion and dye affinity), hydrophobicity and size and its