Microbial growth, the multiplication of microorganisms, is influenced by a variety of environmental factors. These factors can either support or inhibit the growth of microorganisms and include temperature, pH, humidity, and the presence of nutrients and water.
Temperature is a major factor that affects microbial growth. Most microorganisms have a temperature range in which they can grow and multiply, known as the "optimal growth temperature." For example, mesophilic microorganisms grow best at moderate temperatures between 20-45°C, while thermophilic microorganisms require higher temperatures of around 50-80°C to grow. Outside of their optimal temperature range, the growth rate of microorganisms decreases, and they may become inactive or even die.
The pH of the environment is also important for microbial growth. Most microorganisms prefer a neutral pH around 7, but some are adapted to grow in more acidic or basic environments. For example, acidophilic microorganisms can grow in environments with a pH as low as 1, while alkaliphilic microorganisms can grow in environments with a pH as high as 10. If the pH of the environment is outside of the range that a microorganism can tolerate, its growth will be inhibited.
Humidity, or the amount of water vapor in the air, is another factor that affects microbial growth. Most microorganisms require a certain amount of moisture to grow, and the optimal humidity will depend on the specific microorganism. If the environment is too dry, the growth of microorganisms may be inhibited, while excessively humid environments can lead to condensation and the growth of mold and other fungi.
Finally, the presence of nutrients and water are essential for microbial growth. Microorganisms require a source of energy and raw materials to grow, and these are typically provided by the nutrients in their environment. Water is also necessary for microbial growth, as it is required for many of the chemical reactions that take place within the cells of microorganisms. Without sufficient nutrients and water, the growth of microorganisms will be impaired.
In summary, environmental factors such as temperature, pH, humidity, and the presence of nutrients and water play a significant role in the growth of microorganisms. Understanding these factors can help us to better control and manage the growth of microorganisms in various settings, such as in the production of food and beverages, the treatment of wastewater, and the control of diseases.
What environmental factors affect microbial growth?
What is a compatible solute? They would prefer to grow in the presence of oxygen, however, since aerobic respiration generates the largest amount of energy and allows for faster growth. Apart from that, it is important to understand these factors especially in an industrial set up where a huge amount of biomass is needed. Some species of bacteria, remain viable at a temperature of liquid air -190°C and of liquid hydrogen -253°C. Physical Factors that Control Microbial Growth. Similarly, drugs, chemicals, temperature, and light are among the external environmental factors that can determine which genes are turned on and off, thereby influencing the way an organism develops and functions. During short periods of cooling, these species die quite rapidly. Sudden transfer from a concentrated to a weak solution, or to distilled water, may cause plasmolysis i.
What environmental factors can influence microbial growth?
Many microorganisms remain viable at low temperature and viruses are especially resistant to low temperatures. The maximum growth temperature usually reflects the inactivation of one or more key proteins in the cell. Cooler locations tend to slow growth of microbes, as seen when food is refrigerated to keep it safe to eat longer. Aerotolerant anaerobes can also grow in the presence or absence of oxygen, exhibiting no preference. Anaerobic bacteria can grow very well in absence of oxygen and elaborate the toxin which is responsible for the pathogenic effect. What are different environmental factors that affect human health assignment? Nonetheless, a few exceptional microbes actually prefer to grow at very high temperatures or very low temperatures. This rapid division leads to a rapid increase in the population size Figure 3c.
These include several species of Thiobacillus, and several genera of the archaea including Sulfolobus. Every microbe has unique nutritional requirements depending on the types of molecules it is capable of making for itself. Most microbes grow optimally within a certain temperature range dictated by the ability of proteins within the cell to function. Intrinsic factors are those that are characteristic of the food itself; extrinsic factors are those that refer to the environment surrounding the food. The growth of microorganisms can be slowed down or completely stopped by altering the environmental growth factors. For example, high temperatures affect the living cell structures causing death; pathogenic bacteria are capable to produce infection or toxin according to the presence or absence of oxygen. In this situation, one parent cell produces a single daughter cell by a process called Saccharomyces cerevisiae, a yeast used to make bread, is a budding yeast.
What are environmental factors that affect microbial growth?
How does temperature influence microbial growth? For instance, pathogens often grow best at normal body temperature, but slowly at cooler temperatures outside the body or when body temperature increases during a fever. The size of any unicellular microbe is limited by the capacity for the essential components of the cell to support its survival. If however the cells environment has a low aw there is tendency for water to flow out of the cell. Temperature affects the growth of bacteria by various ways. Halophiles, which require a NaCl concentration above 0.
Environmental Factors affecting Microbial Growth Apart from nutritional components growth of the microbes are also dependent on several environmental factors. Only certain species of pathogenic bacteria are very sensitive to low temperature e. For example, the integrity of the cell wall is impaired when cells become too large. Gonococci, meningococci, treponema, leptospira and phages are sensitive to dessication. Moisture Water is an essential component for the growth of the bacteria.
In the presence of oxygen, the same bacteria cannot produce such toxin and, hence, they are not pathogenic. The protoplasm cell substance of all living cells is, therefore, identical. Quick freezing of bacterial and viral suspension at a very low temperature provokes conditions at which crystals do not form and subsequent disruption of the microorganisms does not occur. These microbes, known as Even when nutrients are available and the temperature is right, many other environmental factors can influence the growth of microbes. The activities of microorganisms are greatly affected by the chemical and physical conditions of their environments. Oxygen and Nutrients Oxygen-enriched locations and areas with vital nutrients will cultivate more microbial growth than locations with reduced oxygen levels. Mechanisms of microbial growth Microbial growth refers to an increase in number of cells rather than an increase in cell size.
Different microorganisms require different environments for survival. Osmotic Pressure: Like other living cells, bacteria have a semipermeable cytoplasmic membrane which is subjected to osmotic pressure. Beyond size, microbes are incredibly diverse. May bacteria are able to produce several organic acids which reduce the pH of the medium and also restrict the growth of other bacteria. Microbes with different shapes divide similarly. One of the most critical factors for microbial growth is the availability of nutrients and energy. Bacteria withstand easily atmospheric pressure.
Molly Sargen is a PhD student in the Biological and Biomedical Sciences Program at Harvard Medical School. Above this temperature, cell functions fall sharply to zero. At least it is for microbes. How does pH affect the growth of bacteria? Vibrio cholerae loses its viability at a temperature of -32°C. The rate of growth or death of a particular microbial species is influenced by a variety of physical factors in its environment including temperature, osmotic pressure, pH, and oxygen concentration.
As long as the conditions are favorable, one cell produces two new cells in a continuous cycle. Each organism has a pH range within which growth is possible, and most have well defined pH optima. These microbes have a growth optima of 88-106 oC, a minimum of 65 oC and a maximum of 120 oC. Oxidising Agents: Chlorine is commonly used in decontaminating water, because chlorine acts on dehydrogenase, hydrolase, amylase, proteinase of bacteria; chloride of lime and chloroform are used as disinfectants. Many microbes including Escherichia coli, Salmonella enterica, and Listeria monocytogenes are unicellular, meaning they are made of only one cell. Just like any living thing, water is essential to the life of microbes.
Chapter 3. Factors that Influence Microbial Growth
In this situation water will pass into the cell, causing the cell to swell and increasing internal pressure. This information is for educational purposes only. Dessication in a vacuum at a low temperature does not kill bacteria, rickettsiae, viruses. The facultative anaerobes are the most versatile, being able to grow in the presence or absence of oxygen by switching their metabolism to match their environment. The result effect of overlapping factors determines the possibility of the growth of certain microorganisms. Although each factor affecting growth is considered separately in the following discussion, these factors occur simultaneously in nature. Temperature is the most important factor for the development of microorganisms.