Psychrophile Microorganisms: Adaptations To Low Temperatures In Microbial Life

Microbiology at the Temperature Frontier: Growth of Mesophile and Thermophile Bacteria Name : Minggu Menang Class : 19-A Anaerobic bacteria: bacteria that cannot use free O2 for respiration. Energy is obtained from the process of breaking down organic compounds without the use of oxygen called fermentation. Anaerobic bacteria can be divided into obligate anaerobes and facultative anaerobes. Obligate anaerobic bacteria can only live in the absence of oxygen. Oxygen is toxic to obligate anaerobic bacteria. Examples are Microccocus denitrificans, Clostridium botulinum, and Clostridium tetani. Facultative anaerobic bacteria, can live in the presence or absence of oxygen. Examples include Escherichia coli and Lactobacillus. Bacterial Growth Growth is the process of increasing the size or substance or mass of an organism, for example we macro creatures are said to grow when they increase in height, increase in size or increase in weight. In one-celled organisms, growth is more defined as colony growth, namely the increase in the number of colonies, the size of the colony is getting bigger or the substance or mass of microbes in the colony is increasing, growth in microbes is defined as an increase in the number of microbial cells themselves. Growth is an irreversible life process, meaning that it cannot be reversed. Growth is defined as an increase in the quantity of cellular constituents and structures of an organism that can be expressed by size, followed by increase in number, increase in cell size, increase in weight or mass and other parameters. As a result of the increase in size and cell division or increase in the number of cells, microbial population growth occurs. The term bacterial growth refers more to the increase in the number of cells rather than referring to the development of individual cell organisms. Bacteria have the ability to multiply exponentially because their reproductive system is transverse binary division, where each cell divides into two cells. Bacteria are cosmopolitan organisms that can be found in various places with various conditions in nature. Starting from the hot desert, to the frozen north pole we can still find bacteria. But bacteria also have certain temperature limits that they can survive, there are three types of bacteria based on their tolerance level to the temperature of their environment: 1. Psychrophile microorganisms are microorganisms that like to live at cold temperatures, can grow best at optimum temperatures below 20oC. 2.Mesophile microorganisms, which are microorganisms that can live optimally at moderate temperatures, have an optimum temperature between 20oC and 50oC. 3. Thermophile microorganisms, which are microorganisms that grow optimally or like at high temperatures, these microorganisms often grow at temperatures above 40oC, this type of bacteria can live in hot places even in hot springs this type of bacteria can be found, in 1967 in the yellow stone park found bacteria that live in hot springs with temperatures of 93-94oC. a. Heterotrophic Bacteria Heterotrophic bacteria are bacteria that live by obtaining food in the form of organic substances from their environment because they cannot compose the organic substances they need themselves. Organic substances are obtained from the remains of other organisms, waste, or substances contained in the bodies of other organisms. Bacteria that get organic substances from garbage, feces, carrion, and also food usually called as bacteria saprophytes. Bacteria These bacteria decompose organic substances contained in food into inorganic substances namely carbon dioxide, hydrogen, energy, and minerals. These bacteria function as decomposers and nutrient providers for plants. Important for composting, but detrimental if present in food because it causes food to spoil. The picture beside is the Escherichia coli bacteria found in the human intestine which also lives as a saprophyte. Without this bacteria, we would have difficulty passing stool. Other heterotrophic bacteria are parasitic bacteria, both parasitic on animals, plants, and humans. The need for organic substances is obtained from the host. These bacteria can cause illness so they are called pathogens. Examples of bacteria that live in humans are Clostridium tetani (the cause of tetanus), Mycobacterium tuberculosis (the cause of tuberculosis), and Mycobacterium leprae (the cause of leprosy). b. Autotroph Bacteria These bacteria can compose their own organic substances from inorganic substances so they are called autotrophic bacteria. The conversion of inorganic substances into organic substances is done in two ways, namely: - Uses light energy Light energy is used to convert inorganic substances into organic through the process of photosynthesis. Therefore, bacteria are known as bacteria that They live as photoautotrophs, so they are called photoautotroph bacteria. Examples of these bacteria are green bacteria and purple bacteria. Green bacteria contain green pigments. This pigment is called bacteriochlorophyll. Purple bacteria contain purple, red, or yellow pigments. This pigment is called bacteriopurpurin. Uses chemical energy Chemical energy is obtained when there is a breakdown of chemical substances from complex molecules into simple ones by releasing hydrogen. This type of bacteria is commonly referred to as chemoautotroph bacteria. For example, Nitrosomonas bacteria that break down NH3 into HNO2, water and energy. The energy obtained is used to organize organic substances. Another example is Nitrobacter as shown below.