Microbes are tiny organisms too small to be seen without a microscope, yet they have an enormous impact on human life and industry. This group includes bacteria, fungi (like yeasts and molds), archaea, protists, and viruses, found everywhere from deep-sea vents to the human gut. For centuries, humans have unknowingly harnessed their biochemical power. Modern microbiology allows us to intentionally select and engineer these natural tools for specific applications, transforming fields from medicine to manufacturing.
Microbes in Food and Beverage Production
The controlled use of microbes in food processing, known as fermentation, is one of the oldest forms of biotechnology. These organisms convert carbohydrates into organic acids, gases, or alcohol, changing the food’s flavor, texture, and shelf life. Lactic acid bacteria (LAB), such as Lactobacillus species, are responsible for the sourness and preservation of many dairy and vegetable products. They convert milk sugars into lactic acid, which causes proteins to coagulate, yielding yogurt, cheese, and buttermilk.
In alcoholic beverages and bread production, yeast plays the dominant role. The species Saccharomyces cerevisiae metabolizes sugars to produce ethanol and carbon dioxide. Carbon dioxide causes bread dough to rise, while ethanol is the desired product in beer and wine making. Fermentation also inhibits the growth of unwanted spoilage organisms by creating an acidic or alcoholic environment, increasing food safety and stability.
Microbes in Medicine and Therapeutics
Microbes are directly responsible for creating powerful tools to combat disease, namely antibiotics. Many antibiotics are naturally produced by fungi and soil bacteria to compete with other organisms. For instance, the original penicillin was discovered from the fungus Penicillium.
The majority of natural antibiotics, including streptomycin and tetracycline, are sourced from bacteria belonging to the genus Streptomyces. Scientists cultivate these organisms in large-scale fermenters to isolate and purify the antimicrobial compounds that kill harmful bacteria.
Modern medicine utilizes microbes as biological “factories” through recombinant DNA technology. By inserting human genes into fast-growing microorganisms, scientists instruct them to produce human proteins for therapeutic use. For example, Escherichia coli and Saccharomyces cerevisiae are genetically engineered to produce human insulin. This process allows for the mass production of highly pure, non-animal-derived human insulin, first approved in 1982. Microbes are also used in many vaccines, either as attenuated or killed versions of pathogens, or as production hosts for specific microbial components that trigger an immune response.
Microbes for Environmental Restoration
Microbes offer a powerful, natural solution for cleaning up contamination through bioremediation. This technique uses naturally occurring or introduced microorganisms to break down environmental pollutants into less harmful substances. Oil spills, which consist of complex hydrocarbon chains, are often tackled by oil-degrading bacteria like Alcanivorax and Pseudomonas.
These specialized microbes consume hydrocarbons as a food source, converting them into harmless byproducts like carbon dioxide and water. Microbial activity is sometimes enhanced through bioaugmentation (adding specialized cultures) or biostimulation (adding nutrients to encourage existing microbes). Wastewater treatment facilities rely entirely on massive microbial communities to function, breaking down organic waste in sewage before the water is returned to the environment.
Microbes in Industrial Manufacturing
Beyond food and medicine, microbes are widely employed in industrial manufacturing to produce commercial goods and materials. A primary application is the large-scale production of enzymes, which are biological catalysts used in many processes. Bacteria and fungi are grown in bioreactors to produce enzymes like lipases and proteases, which are added to laundry detergents to break down stains.
Microbial processes are also leveraged to create sustainable alternatives to petrochemical products. Certain bacteria, when stressed, synthesize and store polymers called polyhydroxyalkanoates (PHAs) as energy reserves. Extracted PHAs are biodegradable bioplastics, offering an environmentally friendlier substitute for traditional plastics in packaging and medical applications. Fermentation by various microbial strains is also used to manufacture organic acids like citric acid for food flavoring, or solvents like acetone and butanol for chemical synthesis.