生物工程下游技术一.ppt

第一章 生物反应器Bioreactor Section One Bioreactor A bioreactor is a vessel in which is carried out a chemical process which involves organisms or biochemically active substances derived from such organisms. Bioreactors are commonly cylindrical, ranging in size from some liter to cube meters, and are often made of stainless steel. Bioreactor design is quite a complex engineering task. Under optimum conditions the microorganisms or cells will reproduce at an astounding rate. The vessels environmental conditions like gas (i.e., air, oxygen, nitrogen, carbon dioxide) flow rates, temperature, pH and dissolved oxygen levels, and agitation speed need to be closely monitored and controlled. One bioreactor manufacturer, Broadley-James Corporation, uses vessels, sensors, controllers, and a control system, digitally networked together for their bioreactor system. 1. Introduction Crude medicinal preparations that were aqueous or alcoholic extracts of plant materials were known for centuries to practitioners of the indigenous methods of medicine. The pain-killing salicylates and antimalarial compounds extracted from the bark of certain trees are notable examples of older medicines. Similarly, animal organs such as the pancreas, placenta, and the urine of pregnant females have been a source of hormones for therapeutic use. Until recently, human albumin was manufactured from pools of human placenta collected from Third World countries. But the high risk of virus contamination from unidentified donors of placenta and the impracticality of identifying the donors, forced the discontinuation of this process. Today, plasma from unpaid donors is the major source of albumin and the risk of transmission of viruses calls for extensive purification including the use of dedicated virus removal and inactivation steps to render the product safe for human use. Although crude preparations from plant or animal sources are still used as medicinals in some parts of the world, modern medici