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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 [1]), direct and bulk (biomass), indirect and individual (colony counting), or indirect ...
The Gompertz curve or Gompertz function is a type of mathematical model for a time series, named after Benjamin Gompertz (1779–1865). It is a sigmoid function which describes growth as being slowest at the start and end of a given time period.
Figure 1: A bi-phasic bacterial growth curve.. A growth curve is an empirical model of the evolution of a quantity over time. Growth curves are widely used in biology for quantities such as population size or biomass (in population ecology and demography, for population growth analysis), individual body height or biomass (in physiology, for growth analysis of individuals).
In biology and biological engineering, the change in numbers of microbes due to asexual reproduction and nutrient exhaustion is commonly illustrated by a semi-log plot. Time is usually the independent axis, with the logarithm of the number or mass of bacteria or other microbe as the dependent variable. This forms a plot with four distinct ...
A portable embedded system for microbial concentration measurement in liquid and semi-liquid media using impedance microbiology has been recently proposed. [16] [17] The system is composed of a thermoregulated incubation chamber where the sample under test is stored and a controller for thermoregulation and impedance measurements.
Diauxic growth, meaning double growth, is caused by the presence of two substrates (usually sugars) on a culture growth media, when the microbial cells are capable of faster growth on one of these substrates. The faster-growth supporting substrate is consumed first, which leads to rapid growth, followed by a lag phase. [1]
Incubation follows a growth curve variable for every microorganism. Cultures follow a lag, log, stationary, and finally death phase. [6] The lag phase is not well known in microbiology, but it is speculated that this phase consists of the microorganism adjusting to its environment by synthesizing proteins specific for the surrounding habitat. [6]
Biological exponential growth is the unrestricted growth of a population of organisms, occurring when resources in its habitat are unlimited. [1] Most commonly apparent in species that reproduce quickly and asexually , like bacteria , exponential growth is intuitive from the fact that each organism can divide and produce two copies of itself.