Question

Calculate the time it will take to increase the cell number from 104 CFU/ml to 108 CFU/ml assuming a generation time of 1.5 h.

Answer 1

Answer:

Bacterial growth is a complex process involving numerous

anabolic (synthesis of cell constituents and metabolites) and

catabolic (breakdown of cell constituents and metabolites)

reactions. Ultimately, these biosynthetic reactions result in

cell division as shown in Figure 3.1 . In a homogeneous rich

culture medium, under ideal conditions, a cell can divide

in as little as 10 minutes. In contrast, it has been suggested

that cell division may occur as slowly as once every 100

years in some subsurface terrestrial environments. Such

slow growth is the result of a combination of factors

including the fact that most subsurface environments are

both nutrient poor and heterogeneous. As a result, cells are

likely to be isolated, cannot share nutrients or protection

mechanisms, and therefore never achieve a metabolic state

that is efficient enough to allow exponential growth.

Most information available concerning the growth of

microorganisms is the result of controlled laboratory studies

using pure cultures of microorganisms. There are two

approaches to the study of growth under such controlled

conditions: batch culture and continuous culture. In a batch

culture the growth of a single organism or a group of organisms, called a consortium, is evaluated using a defined

medium to which a fixed amount of substrate (food) is

added at the outset. In continuous culture there is a steady

influx of growth medium and substrate such that the amount

of available substrate remains the same. Growth under both

batch and continuous culture conditions has been well characterized physiologically and also described mathematically.

This information has been used to optimize the commercial

production of a variety of microbial products including antibiotics, vitamins, amino acids, enzymes, yeast, vinegar, and

alcoholic beverages. These materials are often produced in

large batches (up to 500,000 liters) also called large-scale

fermentations.

Explanation: