To use all functions of this page, please activate cookies in your browser.
With an accout for my.bionity.com you can always see everything at a glance – and you can configure your own website and individual newsletter.
- My watch list
- My saved searches
- My saved topics
- My newsletter
Bacterial growth is process in which two clone daughter cells are reproduced by the cell division of one bacterium. Hence, local doubling of the bacterial population occurs. Both daughter cells from the division do not necessarily survive. However, if the number surviving exceeds unity on average, the bacterial population undergoes exponential growth. The measurement of an exponential bacterial growth curve in batch culture was traditionally a part of the training of all microbiologists; the basic means requires bacterial enumeration (cell counting) by direct and individual (microscopic, flow cytometry), direct and bulk (biomass), indirect and individual (colony counting), or indirect and bulk (most probable number, turbidity, nutrient uptake) methods. Models reconcile theory with the measurements .
Additional recommended knowledge
In autecological studies, bacterial growth in batch culture can be modeled with four different phases: lag phase (A), exponential or log phase (B), stationary phase (C), and death phase (D).
This basic batch culture growth model draws out and emphasizes aspects of bacterial growth which may differ from the growth of macrofauna. It emphasizes clonality, asexual binary division, the short development time relative to replication itself, the seemingly low death rate, the need to move from a dormant state to a reproductive state or to condition the media, and finally, the tendency of lab adapted strains to exhaust their nutrients.
Batch culture is the most common laboratory growth environment in which bacterial growth is studied, but it is only one of many. It is ideally spatially unstructured and temporally structured. Bacteria are presented with a single burst of nutrients and left to their own devices. In some experimental regimes, they are periodically removed to a new batch of nutrients. In the extreme case, this leads to the continual renewal of the nutrients. This is a chemostat aka continuous culture. It is ideally spatially unstructured and temporally unstructured, in an equilibrium state defined by the nutrient supply rate and the reaction of the bacteria. Related devices include turbidostats and auxostats.
Liquid is not the only laboratory environment for bacterial growth. Spatially structured environments such as biofilms or agar surfaces present additional complex growth models.
Bacterial growth can be suppressed with bacteriostats, without necessarily killing the bacteria. In a synecological, a true-to-nature situation, where more than one bacterial species is present, the growth of microbes is more dynamic and continual.
==This article includes material from an article posted on 26 April 2003 on Nupedia; written by Nagina Parmar; reviewed and approved by the Biology group; editor, Gaytha Langlois; lead reviewer, Gaytha Langlois ; lead copyeditors, Ruth Ifcher. and Jan Hogle.
|This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Bacterial_growth". A list of authors is available in Wikipedia.|