Factors that Affect Bacterial Growth

There are many factors that affect bacterial growth. Before we go over these factors we must however understand the bacterial growth curve. The Lag phase is when the bacterial cell increases in size, the Log phase is when the cells increase in number, the Stationary phase is when cells begin to die off and finally the Decline phase is when the number of dead cells exceeds the number of cells being made.

This brings us to one of the obvious factors that affect bacterial growth which is space and resources available. If a cell is growing in artificial media and uses up all of the nutrients quickly then that will affect it’s growth rate. This means that that growth depends on the quality and availability of resources which we will consider later on.

Another factor we must first consider is whether the bacterial cell is able to live in humans or live in other environments. Whether or not the microbe affects humans all bacterial cells have optimum conditions at which they grow. For example, human pathogens grow optimally when the pH of the media is around 7 and the temperature is between 35 to 37 degree Celsius. Some bacterial cells grow better in acidic or basic environments others may only grow in extremely warm temperatures. Microbes will therefore better when they are in their optimum environment.

To continue atmospheric requirements is also a factor that affects bacterial growth. If the bacteria is an anaerobe, which means it does not need oxygen to grow, it will grow better in an environment that lacks oxygen. Some cells require a certain percentage of carbon dioxide in order to grow at maximum potential. If a bacteria does need oxygen, they’re considered to be aerobes.
It is also important to consider the nutrients the bacteria needs in order to continue multiplying.  The nutrients come in various sources including carbon, nitrogen and various inorganic ions. These are all factors that ensure the growth of the cell. Water is also very important for the growth of microbes and for every living organism. Specific growth factors may also be required such as blood or specific type of protein. If an organism requires many of these specific growth factors they may be considered “fastidious”.

To finish the main factors that affect bacterial growth are resource availability, metabolism, temperature, pH, atmosphere and nutrients. There are numerous bacteria with specific requirements and it is important to remember that not all bacteria grow in the same conditions.