生物分离工程3细胞破碎08.ppt.Convertor.doc

生物分离工程 （三） 细胞破碎 细胞破碎的方法 机械方法 物理方法 化学方法 生物方法 等。 Summary 概述 Bioseparations usually begin with the separation of biomass from broth .The separation commonly uses filtration or centrifugation as described in Chapters 1 and 2. In many cases, the desired product is in the broth. Antibiotics, are commonly in the broth; so are extracellular enzymes, many polysaccharides, and most amino acids. In all these cases, the separated broth can be treated to isolate and purify the product, as a byproduct. 生物分离的第一步是将生物机体从发酵液中分离，通常使用过滤和离心等方法，这在第一、二章中已有陈述。大多数情况下，抗生素，胞外酶，一些多糖，及氨基酸等目标产物存在于在发酵液中。在上述过程中，需被分离的发酵液可被看作一种副产物来处理，以此分离和纯化产物。 In some cases, the products of interest are not in the broth but are in the biomass. In particular, most proteins produced in quantity by genetically manipulated bacteria are not excreted into the broth, but are precipitated within the cell. Lipids and some antibiotics are also trapped in the biomass. In a few cases, like baker’s yeast, the desired product is the cell mass itself. In a few others, desired products like steroids can be extracted without rupturing the cells. In many cases, the product is trapped in the biomass: It is intracellular. 有些目标产物不在发酵液中，而是存在于生物体中。尤其是由基因工程菌产生的大多数蛋白质不会被分泌到发酵液中，而是在细胞内沉积。脂类物质和一些抗生素也是包含在生物体中。还有一些目标产物就是细胞本身，如面包酵母。还有，产物如类固醇不必通过细胞破碎提取。大多数情况下，产物还是包裹在生物体内，属胞内产物。 Releasing this trapped material usually involves rupturing the cell wall, and is the subject of this short chapter. The methods of cell rupture have largely been developed in biochemistry, and hence are of small scale. Their application to the larger scale operations implied by genetic engineering is speculative. The equipment which is used is not designed for biotechnology. 使胞内产物释放出来一般需要破碎细胞壁，这也是这一章的主题。细胞破碎的方法在生物化学领域中得到了很广泛的运用，但多数在小规模生产中，在大规模生产尤其是基因工程中应用极少。 In this chapter, we begin by reviewing the structure of the cell wall. We then consider the methods for cell rupture most likely to be useful at larger scales. These methods, listed in Table , are conveniently sp