Benefits of microorganisms to humans:
Microorganisms are involved in the production of food or are directly edible.
Examples: - Various types of yeast (a type of fungus): Used for the production of beer, bread, and cheese.
spirulina is a blue green algae used as
SCP (single cell protein) in human beings for their protein source.
It may come as a surprise but there are several billion times more bacterial cells inside your body than there are human cells. They make up the human flora. Luckily, some live in a mutualistic relationship to you. That is, they receive something (generally nutrients) from you, but also give something in return. The presence of bacteria also inhibits the growth of potentially pathogenic bacteria (usually through competitive exclusion).
Provided the normal flora remains balanced, you are less likely to become ill with pathogenic bacteria. Everyone has small amounts of potentially pathogenic bacteria included in their normal flora. S.aureus and S.pyogenes remain on the skin quite harmlessly as part of the normal flora until your immunity is depressed and the skin is broken. I do not consider E.coli an exception to any rule (as previously mentioned in this answer) - any type of bacteria can be harmful to someone with lowered immunity. Most strains of E.coli are perfectly harmless and in fact protect you against the more harmful enteric pathogens as part of the normal intestinal flora.
Examples: - Gut bacteria: synthesize vitamins such as folic acid, vitamin K and biotin, and they ferment complex indigestible carbohydrates.
We have vastly developed or discovered direct uses for microorganisms in recent years. Modern biotechnology is often associated with the use of genetically altered microorganisms such as
E. coli or yeast for the production of substances like synthetic insulin or antibiotics. Using the same process, a multitude of drugs are manufactured relatively cheaply, including human growth hormone, clotting factors for hemophiliacs, fertility drugs, erythropoietin and other drugs.
Biotechnological advances in agriculture also require the help of microorganisms. Transgenic plants can increase yield, reduce vulnerability to environmental and pathogenic stresses, improve taste and appearance and produce novel plant substances. To create transgenic plants, a vector,
Agrobacterium, is required to transfer genetic material into the plant host.
Micro-organisms also naturally have desired products or effects. These include substances that fight human pathogens, insecticidal properties, and bio-degradation properties, to name a few.
In fact, advances in the understanding of biological phenomena, the science of biology that facilitates medical, agricultural, and food advances, are not possible without model microorganisms including:
E. coli,
B. subtilis, Phage λ, Tobacco mosaic virus, and
S. cerevisiae to name a few.
As humans are eukaryotes, our genome is extremely difficult to truly decode due to processes such as exon shuffling, the genetic "junk" and likely dozens of other observed aspects of our genome.
Naturally, many people with genetic defects need a constant supply of medicines (diabetics will be used from here on out in this section). Creating insulin in a lab was very difficult before the onset of cDNA, which (long story made really really short) is placing the human insulin gene into yeast or another simple eukaryote. Thankfully, all eukaryotic cells "know" how to process our genome and human hormones can be made
in vivo in laboratories in greater quantity than ever before
Microbes are involved in cycling vital elements such as carbon and nitrogen, breaking down wastes and dead organisms into simpler substances plants can use in photosynthesis. Other species are at the base of the food chain, especially in aquatic ecosystems. Even pathogens have a role in controlling the populations of their host species. Microbes are used to digest oil from oil spills.