chapter4 细胞破碎

TABLE 4.0-1. Chemical Cell Disintegration Techniques
Method Chemical Technique Osmotic shock Principle Osmotic rupture of membrane Cell wall digested , providing disruption Stress Gentle Cost Cheap Examples Rupture of red blood cells Egg lysosyme
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
Ultrasonication
Harsh
Expensive
Cell suspensions at least on a small scale Large scale treatment of cell suspensions,
Homogenization (orifice type)
Harsh
Moderate
Lipid dissolution
Organic solvent dissolves in cell wall
Moderate
Cheap
Alkali treatment
Saponification of lipids solubilizes membrane
Harsh
Cheap
表 4.0-1. 细胞化学破碎法
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，这在第二、三章中已有陈述。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。
方法
技术
原理
效果
成本
举例
化学法
渗透冲击
酶消化法 增溶法 脂溶法 碱处理法
渗透压破坏细胞
细胞壁被消化，使 细胞破碎 表面活性剂溶解细 胞壁 有机溶剂溶解细胞 壁并使之失稳 碱的皂化作用使细 胞壁融解
温和
温和 温和 适中 剧烈
便宜
昂贵 适中 便宜 便宜
血红细胞的破 坏
胆盐作用于大 肠杆菌 甲苯破碎酵母 细胞
In this chapter, we begin in Section 4.1 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 4.0-1, are conveniently split into two groups, described as “chemical” and “mechanical.” In the chemical methods detailed in Section 4.2, the cell membrane is ruptured by osmotic pressure, dissolved by detergents, or enfeebled by organic solvents. These chemical cases are often gentle so that the products are not irreversibly denatured even while the cells are ruptured. Scale-up is easy: If we want to treat 10 times the biomass, we need to use 10 times as much chemical.
methods described in Section 4.3 are dominated by homogenization and by ball mill grinding. In both cases, cells are broken by high mechanical shear. Heat generation is a problem and scale-up is obscure: If we find that a method works at a laboratory scale, we often have little idea how it will work at a large scale. As a result, this part of the chapter is more a guide to planning experiments than a synopsis of engineering analysis. 4.3节机械法主要有匀浆法和研磨法。这两种方法中，细胞通过高的机 械剪切力被破坏。热量的产生是该法的一个缺点，而且不容易规模放 大:如果一种方法可以在实验室规模下操作，我们并不知道这种方法是 否在大规模生产中可行。所以，这部分内容仅作为实验的指导，而不 是工程分析。
机械法
匀浆法（片型）
研磨法 超声波法 匀浆法（孔型）
细胞被搅拌器劈碎 适中
细胞被研磨物磨碎 适中 用超声波的空穴作 适中 用使细胞破碎 须使细胞通过的小 剧烈 孔，使细胞受到剪 切力而破碎 细胞被玻璃珠或铁 剧烈 珠捣碎
适中
便宜 昂贵 适中
动物组织及动 物细胞
细胞悬浮液小 规模处理 细胞悬浮液大 规模处理 细胞悬浮液和 植物细胞的大 规模处理
Grinding
Cells ruptured by grinding with abrasives
Cells broken with ultrasonic cavitation Cells forced through small hole are broken by shear
Moderate
Cheap
※ 4.1 Cell Membranes
细胞膜
At this point, we pause briefly to explore the physical structure of microbial membranes and the complexity of the problems which we face. At present, knowledge of this general structure does not provide a direct guide to methods of cell rupture. In the future, it may. As a result, we feel that a synopsis has merit. In this synopsis, we emphasize Gram-negative procaryotes. 本节主要探寻细胞膜的物质结构及我们所面对的几个复杂问题。现在所
4.1节回顾一下细胞壁的结构。从中可知，在大规模生产中，细胞破碎方 法是十分有用的。我们很容易将这些方法划分为两大类，化学法和机械 法，表4.0-1中已经列出。化学法我们将在4.2节作详细介绍，有渗透冲 击法、表面活性剂增溶法或有机溶剂溶解法。这些化学法较温和，细胞 破坏后产物也不会不可逆的变性，规模也容易放大：如果需要处理10倍 量的生物有机体，只需要加入10倍的化学药品剂量。
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。
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。
Chapter 4
Cell Disruption
第四章 细胞破碎
※ 4.0 Summary
概述
※ 4.1 Cell Membranes 细胞膜
※ 4.2 Chemical Methods