(438f) Advances in Centrifugal Separation in Biotechnology

Wallace Woon-Fong Leung

Mechanical Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong

Abstract

Centrifugal separation has been used to recover recombinant protein after fermentation using, respectively, bacteria, mammalian cells and yeast as host cells. The separation is being tuned to the special requirements for each process. For example, for mammalian cells are highly sensitive to shear due to absence of a cell wall as with yeast or bacteria. High shear in the feed acceleration can lead to lysing of the cell thereby spoiling the entire batch. We will discuss possible provision whereby this can be minimized. For bacterial cells, the protein is produced inside the cell and the bacteria have to be lysed before the separation by centrifugation. Separation followed by reslurrying/washing are required. The issue is to how to effectively separate and purify the protein before downstream purification by the column. For yeast processing, the requirement is to extract to high yield with minimal processing. Typically, a two-stage separation is required to warrant high yield. In addition to protein harvest, there are numerous biotech separation processes that require high yield, high purity, high concentration of the solid phase, solid-free centrate liquid, etc. Technological advancement in the continuous centrifuges, such as the disc nozzle centrifuges, and semi-continuous centrifuges, such as the intermittent disk and the tubular centrifuges are also discussed. The decanter is also used to process bioproducts, especially the waste stream. Flocculation can be used to enhance separation. The optimal floc size and minimum polymer dosing are of great interest. Various challenges and opportunities will be discussed in the presentation.

Biography of Wallace Woon-Fong LEUNG

Prof. Wallace W-F Leung received his MS and ScD both in Mechanical Engineering from MIT. For the past 40 years, he has worked on filtration and separation from ultrafiltration of protein solution, centrifugation of process stream, vacuum filtration of minerals, to air filtration. For 18 years, he was with Bird/Baker Hughes as Senior Research Scientist and Director of Process Technologies directing centrifugal separation/filtration. Earlier, he has worked for Gulf Oil and Schlumberger on flow in petroleum reservoirs. For the past 14 years, he is Chair Professor of Innovative Products and Technologies at The Hong Kong Polytechnic University. Wallace’s research interest is in centrifugation of bioprocesses. Besides, he is also interested in applications of nanofiber technologies in separating nano-aerosols, renewable energy (photovoltaics, hydrogen production using water spliting), clean air and water (photocatalysis), and health technologies (wound dressing).

He is well known in the world for his work in centrifugation. He is author of the 1998 McGraw-Hill book “Industrial Centrifugation Technology” and 2007 Elsevier/AP book “Centrifugal Separation for Biotechnology”. He has 36 US patents on centrifugation and 13 US patents on other technologies.

Dr. Leung is a fellow of American Institute of Chemical Engineers, American Society of Mechanical Engineers, American Filtration and Separations Society, Hong Kong Institute of Engineers, and Hong Kong Academy of Engineering Sciences. He is the Chairman for the World Filtration Congress in 2004 (New Orleans) and 2020 (San Diego). He is also Chairman for the International Delegation on Filtration 2016-2020 with 12 member countries, overseeing the world Filtration Congress and promoting filtration and separation activities worldwide.