Bacteria; they’re not all bad!

Bacteria are found pretty much everywhere on the Earth, be it the ocean, acidic hot springs, soil, Antarctica and even 11 000 m deep down in the Marianas Trench. Much has been documented about bacteria and their role in various diseases such as tuberculosis, pneumonia and cholera, as well as causing food poisoning.

Yet, the importance of bacteria seems to be overlooked by the general public, as the press is largely focused on the pathogenic (disease causing) bacteria. As bacteria can’t speak for themselves, I’ll talk on their behalf about how important they are to us.

Now, you may think that plants and trees provide the oxygen available for us to breathe in, but credit must be given to the ‘Cyanobacteria’- in particular the family of Prochlorococcus. This bacterium is the one of the most abundant species in the world, with 1ml seawater containing up to 100 000 cells. Part of the Cyanobacteria uses CO2 to make itself sugars whilst releasing oxygen, much like plants. Up to 20% of the oxygen in the atmosphere is made by these organisms that are just 0.00006cm in length.

The growth of plants and crops requires not only light, water and CO2, but also nitrogen. The problem isn’t a lack of nitrogen; it’s just that plants can’t use the atmospheric version to their advantage. Nitrogen fixing and nitrifying bacteria solve this issue, converting nitrogen into a more functional form, allowing proteins to be made in the plant. This has huge impacts on agriculture and food production and also for the cycling of nitrogen in the atmosphere.

Cheese lovers will be glad to know that bacteria get a very honourable mention as well. Lactobacilli use the lactose in milk and convert it into lactic acid causing the coagulation of milk proteins into curds. They also play a part in the ripening stage of cheese production, helping flavour the cheese. The vinegar you splash on your chips is made by ‘Acetic acid bacteria’- they use ethanol as a food source to produce the main ingredient acetic acid. So whether it’s balsamic or malt, both will have exploited these bacteria.

One of the most crucial uses of bacteria is in genetic engineering. By introducing foreign genes into a DNA molecule the gene products can be made by inducing growth of the bacteria and secretion of the gene product. Type 1 diabetics the world round rely on insulin injections to control their blood glucose levels, and that insulin is now produced as a result of this ‘Recombinant DNA Technology’. Human Growth hormone is also produced in the very same way.

We can also harvest antibiotics from certain groups of bacteria, such as Streptomyces. Their importance is not understated, a staggering 200,000 tonnes are used a year. B12 which affects DNA synthesis can be made by Pseudomonas denitrifcans to make supplements outside of the human gut, allowing vegetarians and vegans to forgo the eating of meat but still gain the vitamin.

These examples are by no means an exhaustive list; bacteria play many more roles in shaping our world. I hope that their importance is not overshadowed by their negative press as we should be truly amazed at what they can achieve to help humans.

“What you see is that the most outstanding feature of life’s history is a constant domination by bacteria”– Stephen Jay Gould

 

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