Microorganisms were completely unknown to science until 1676 when Antonie van Leeuwenhoek observed bacteria for the first time on a hand-crafted single-lens microscope. Another 200 years would pass before Louis Pasteur provided the first evidence supporting the germ theory of disease. In today’s world of disinfectants and pocket hand sanitizers it’s hard to imagine a time when bacteria were considered passive free-loaders and doctors didn’t feel the need to wash their hands. Today bacteria get a bad rep and while some of that is deserved – E. coli, MRSA and tuberculosis outbreaks are frequently in the news – many more species of bacteria are harmless or even beneficial to humans.
The Microbiome
Humans have co-evolved to a state of mutual interdependence with a diverse community of microbes. Each microbiota is and contains hundreds of different species. In fact there are ten times as many bacterial cells as human cells in the body and the microbiome – the collective genome of the host and its microbiota – is 100 times larger than the human genome alone. The beneficial effects of the microbiome are many; the gut microbiota in particular has a role in our development, nutrient uptake and metabolism, and immune defense.
Bacteria in the human gut provide us with functions that are not fully developed in humans. They help us to breakdown indigestible carbohydrates and synthesize vitamins such as folic acid and vitamin K from the food we take in. More efficient breakdown of nutrients also means efficient extraction of fat from the diet. Admittedly, this may be more of a disadvantage in the western world with its overabundance of deep-fried food items. Many studies are even looking into a potential link between the obesity. However, when food is scarce it would be helpful to have gut microbes that can give you the most bang for your buck.
It might seem that carrying such a high bacterial load would weaken the human immune system but in reality it is critical to normal immune development. The natural colonization of the gut by bacteria promotes tolerance of innocuous immunodeterminants by the immune system. This reduces the prevalence of allergic responses to food and environmental stimuli. Simply by competing for resources, a healthy microbiota can also protect the host against colonization by pathogenic species.
Bioremediation
Bioremediation is the process by which bacterial metabolism can be used to remove or reduce pollution. While bioremediation can occur naturally it can be induced or optimized through the genetic manipulation of bacteria. The generation of genetically engineered Deinococcus radiodurans – the most radiation resistant organism- can be used to detoxify ionic mercury found in radioactive waste. Hydrocarbon digesting bacteria can be used to clean up oil spills. Modified bacteria can greatly reduce the costs associated with the containment and clean-up of radioactive wastes, oil spills and other pollutants.
Other Industrial Uses
Many bacterial species are also used in the production of foods like cheese and wine – arguably the most important food groups. They can also be used for biological pest controls which are better for the environmental and human health than typical chemical based pesticides. can also be bioengineered for the production of therapeutic proteins, well-known example being insulin.
Though the emergence of new and antibiotic resistant pathogens poses a significant problem to our health, humans have developed a mutualistic relationship with many more species of harmless bacteria on an individual and an industrial level. Whether they aid in digestion or immune development, produce therapeutic compounds, clean up pollutants or just have a role in the production of wine, many types of bacteria are critical to human health.
