What are the requirements for bacterial growth?
There are several factors contributing to bacterial growth, of which these can be very specific to different types of bacteria, but in general it is as follows.Nutrients is the most important factor, since without it, bacteria simply cannot grow. In a laboratory, nutrients is normally supplied in nutrient media (liquid = broth, solid = agar gel). Media provide key nutrients such as water, a source of carbon, a energy source and a source of nitrogen. Growth factors are also required, such as vitamins. Temperature is another key factor for bacterial growth. Bacterial metabolism is regulated by enzymes, which have optimum temperatures they work at. For mammalian pathogens this is around 37oC. pH is one of the other key factors contributing to bacterial growth. Most bacteria favour slightly alkaline conditions (pH 7.4). However, likewise with temperature, these values can fluctuate depending the specific favourable conditions for different types of bacteria. Oxygen, is the final key factor for bacterial growth. Many microorganisms require oxygen for metabolism and are known as obligate aerobes. Some grow best in presence of oxygen but can survive without it and are called facultative anaerobes. Others cannot grow in the presence of oxygen and are obligate anaerobes.
