Continuous CultureIt is possible to

Continuous Culture

It is possible to have culture of bacteria in the exponential growth phase and hold them there. This is done by continuously adding more nutrients and remove wastes. This is done in a chemostat. Appendix 7 shows a chemostat.

Inputs to a chemostat are sterile media and sterile air. Outputs are spent media which contains waste products, some nutrients and some bacteria.

Flow rate of media and nutrient concentration are controlled. This allows control of the specific growth rate over a wide range. If the flow is too fast, the microorganisms cannot keep up. They leave the chemostat more rapidly than they are produced. Eventually they are all gone. This condition is called ‘washout’. If the nutrient flow is too slow, then it behaves much like a batch culture.

Batch culture means that the volume of media is constant and there is no media added or taken away.

Counting Microbial Cells

Microbial cells can be counted directly or cell count plating methods can be used.

In the direct count method a Petroff-Hauser counting chamber is used. This is glass slide that fits on the stage of a microscope. It has a small depression of known volume. There is a grid on the slide. By determining the number of organisms per square in the grid, an estimate of the number of microorganisms can be made.

There are a number of problems with this method.

1) Dead cells cannot be distinguished from live cells.
2) Small cells are difficult to see.
3) Precision is difficult to attain ภาษาไทย

ผลลัพธ์ (ไทย) 3:

连续文化这是一个有可能的细菌在指数生长培养中，他们知道这是持有和通过继续做了。nutrients和remove wastes adding更多。这是在一个chemostat Done。Appendix 7 A chemostat凝集。Inputs chemostat是到一个输出sterile sterile媒体和媒体的空气。这是花了一些nutrients废物产品，包括和一些细菌。营养浓度和流媒体的速率控制的术语。这是在一个特定的增长率的一个是的。如果range microorganisms流太快，不能跟上的。他们把更多的是比他们chemostat rapidly produced。他们都跑了。这是Eventually条件是被称为“washout营养流的。如果它是太慢，然后behaves多像一个批处理文化。这是批处理培养的体积是常数的媒体和媒体的taken离开或是无说。Counting Microbial Cells细胞可以是直接或Microbial counted镀方法可以是用细胞计数。直接计数的方法，在一个Petroff-Hauser counting室是用玻璃幻灯片。这是在这一阶段和适合。它有一个小凹陷。当已知体积的网格是一个由determining的幻灯片。在每平方organisms number of在一个网格，估计的microorganisms number of是可以做。有问题，这是一个与number of method。1）从细胞死亡是细胞distinguished不能生活。对小细胞2）是困难的人。一个困难是实现精密3语）