Antagonistic Microorganisms

Antagonistic microorganisms are microorganisms that are able to inhibit the growth or activity of other microorganisms through various mechanisms, such as competition for nutrients or production of antimicrobial compounds. The study of antagonistic microorganisms has gained significant attention in recent years due to the increasing prevalence of antibiotic resistance and the need for alternative approaches to controlling microbial growth. In this literature review, we will explore the different types of antagonistic microorganisms, their mechanisms of action, and their potential applications in various fields.

Types of Antagonistic Microorganisms

There are several types of antagonistic microorganisms, including bacteria, fungi, and viruses. The most common types of antagonistic microorganisms are bacteria, which can produce various antimicrobial compounds to inhibit the growth of other bacteria or fungi. For example, Bacillus subtilis is a soil bacterium that produces antibiotics such as bacitracin, polymyxin, and subtilin, which are effective against a broad range of pathogenic bacteria and fungi (Kremer et al., 2018). Similarly, Streptomyces species are well-known for their ability to produce various antibiotics, such as streptomycin and tetracycline, which are widely used in human medicine (Schneider et al., 2012).

Fungi are also known to produce a wide range of antimicrobial compounds, such as polyketides, terpenes, and peptides. One example is the fungus Penicillium chrysogenum, which produces the antibiotic penicillin, one of the most widely used antibiotics in the world (Demain, 2014). Other examples include Trichoderma spp. and Aspergillus spp., which are known to produce antifungal compounds and have potential applications in agriculture as biocontrol agents against plant pathogens (Contreras-Cornejo et al., 2016).

Viruses are another type of antagonistic microorganism, although their mechanisms of action are quite different from those of bacteria and fungi. Viruses can infect and kill specific bacteria, known as bacteriophages, and have been explored as a potential alternative to antibiotics for controlling bacterial infections (Pires et al., 2016). For example, the bacteriophage T4 has been shown to be effective against antibiotic-resistant strains of Escherichia coli (Wright et al., 2009).

Mechanisms of Action

Antagonistic microorganisms can inhibit the growth or activity of other microorganisms through various mechanisms. One common mechanism is competition for nutrients, where antagonistic microorganisms outcompete other microorganisms for essential nutrients, such as carbon, nitrogen, and phosphorus. This reduces the availability of nutrients for other microorganisms and can slow or halt their growth (Kremer et al., 2018).

Another mechanism is the production of antimicrobial compounds, which can be either bactericidal or bacteriostatic. Bactericidal compounds kill bacteria outright, while bacteriostatic compounds inhibit their growth without killing them. Antimicrobial compounds can be produced by antagonistic microorganisms either as secondary metabolites or as part of their primary metabolism (Demain, 2014).

Some antagonistic microorganisms can also produce enzymes that degrade the cell walls of other microorganisms. For example, some Bacillus spp. produce chitinases, which degrade the chitin in the cell walls of fungi (Schneider et al., 2012). Other enzymes produced by antagonistic microorganisms include proteases, lipases, and cellulases, which can break down proteins, lipids, and cellulose, respectively (Contreras-Cornejo et al., 2016).

Applications

Antagonistic microorganisms have potential applications in various fields, including agriculture, medicine, and biotechnology.

Antagonistic microorganisms are used as biological control agents to control plant diseases. These microorganisms can compete with pathogenic microorganisms for nutrients and space, and they can also produce antimicrobial compounds that inhibit the growth of pathogens. For example, the bacterium Bacillus subtilis is used to control fungal pathogens in crops.

Antagonistic microorganisms can be used to prevent the growth of spoilage and pathogenic microorganisms in food. They can be added to food products to prevent spoilage, extend shelf life, and improve safety. For example, lactic acid bacteria are used in the production of fermented foods like yogurt and cheese.

Antagonistic microorganisms can be used in bioremediation to clean up environmental pollutants. These microorganisms can degrade or transform toxic substances into harmless compounds. For example, the bacterium Pseudomonas putida is used to degrade petroleum products in contaminated soil and water.

Antagonistic microorganisms can be used to prevent and treat infectious diseases. They can compete with pathogenic microorganisms for resources and produce antimicrobial compounds that inhibit their growth. For example, probiotics containing beneficial bacteria like Lactobacillus and Bifidobacterium are used to prevent and treat gastrointestinal infections.

Overall, antagonistic microorganisms have various applications in different fields, and their use can provide many benefits, including improved crop yields, safer food products, cleaner environments, and better health outcomes.