HOW IT WORKS
bacteria yeast microbiology bioremediation medicine microbes genetic engineering bioreactors

Our teeny tiny friends and their huge potential

Employee of the Month - Hire a Microbe to Do Your Work

Thought that microbes were only important for our health and making food for us? Turns out these little factories still have a lot more to offer.

We have learned that microbes can be beneficial to us when they are part of a healthy gastrointestinal microbiome or when they help make cheese. We also know that they can cause disease in a variety of ways. But what about less known roles that microbes play when they do our dirty work for us or act as our custom made factories? Humans use microbes to do many different jobs – some jobs can be carried out thanks to natural abilities, while other jobs require genetic engineering of microbes so that they can serve a particular purpose. Either way, as technology progresses and humans face more challenges, we get more creative with what we can get our little friends to do for us.

One example of using microorganisms to (quite literally) clean up our mess is bioremediation, in which microbes clear pollution in the environment for us (Fig. 1). In cases of oil spills, we introduce bacterial and fungal species known to be naturally oleophilic, which means that they love oil and will take up certain hydrocarbons to use as food. Researchers have isolated bacterial species that have shown great promise and are already being used for this purpose, such as Corynebacterium, Bacillus, Brevibacillus and Staphylococcus species [1]. This area of research has still not reached its full potential and there is still much work that needs to be done before microbes can be used to properly clean up petroleum spills and save ecosystems from such catastrophes.

image alt text

Fig. 1 Oil spills destroy entire ecosystems – what if microbes could save the day? Source

In addition to saving the environment, microbes are also used as little factories to synthesize molecules that humans require, such as vitamins. For example, vitamin B12 is required in humans for proper cellular function, yet we cannot produce it ourselves; we have to acquire it through our diet. Deficiency in this vitamin may result in devastating disorders, which is why many people supplement their diet with B12 tablets. But where do these tablets come from? Well, chemically synthesizing B12 from scratch requires over 70 steps and is not cost efficient, which rules it out for commercial manufacturing. However, it turns out that the most common alternative is taking advantage of microbial abilities by filling bioreactors with these bacterial cells (Fig. 2), where they can produce B12 that is then harvested and used to make B12 tablets. The top choices for this practice include Pseudomonas and Propionibacterium, which naturally produce high levels of this vitamin [2].

image alt txt

Fig. 2 An example of a commercial bioreactor (Source: Wikipedia)

Taking advantage of existing microbial abilities may sound like a no-brainer, but technology also allows us to engineer microbes so that they have added functions to help us in new and exciting ways. The ability to take human genes needed for production of insulin and express them in the bacterium Escherichia coli was a huge medical breakthrough in the late 1970’s. This was great news to patients suffering from diabetes, whose pancreases could not produce insulin, a hormone that is critical in maintaining proper blood sugar levels, and the absence of which may wreak havoc on the body (Fig. 3). Nowadays both E. coli and Saccharomyces cerevisiae are used to produce insulin to treat diabetes [3]. If the name Saccharomyces cerevisiae *sounds familiar, it might be because you’ve heard it in the context of “brewer’s yeast” or “baker’s yeast”. Both the bacterium *E. coli and this yeast have been studied by researchers for so long and so thoroughly that we now know them well enough to engineer these species so that they can act as our custom made manufacturing units.

image alt txt

Fig. 3 Diabetics needs insulin to regulate their blood sugar levels Source

Ecological disasters and human disease are only two of many different problems for which scientists are exploring creative microbial solutions. One major problem that we face today is with animal agriculture. Scientists are concerned by the impact that factory farms are having on greenhouse gas emissions, habitat destruction, water usage, and pollution [4]. In addition, moral issues regarding animal welfare arise from common husbandry practices. One approach for handling this conundrum is… you guessed it - get microbes to do it for us! Startup companies are working on expressing milk producing genes in baker’s yeast. Obviously we will not be milking little yeast cells – instead, imagine massive bioreactors full of yeast cells simply secreting a liquid that is identical to cow’s milk on the molecular level, but does not require the resources or the questionable practices associated with raising livestock. If you’d like to learn more about this exciting project, check out the video at the bottom of this news story!

How lucky are we, to live in a time when science continues to expand its limits, exploring ideas of using microbes as our little helpers? Such ideas were once thought to be crazy and are now an inseparable part of human life around the globe. As more knowledge is acquired regarding new microbial species as well as the funky abilities of familiar species, the more solutions we may find using our microscopic friends. These bugs may be tiny, but the potential they hold is pretty darn massive.

References

[1] Macaulay, Babajide Milton, and Deborah Rees. “Bioremediation of oil spills: a review of challenges for research advancement.” Annals of Environmental Science 8 (2014): 9-37.

[2] Hugenschmidt, S., Miescher Schwenninger, S. and Lacroix, C. (2011). Concurrent high production of natural folate and vitamin B12 using a co-culture process with Lactobacillus plantarum M39 and Propionibacterium freudenreichii DF13. Process Biochem, 46: 1063–1070. DOI:10.1016/j.procbio.2011.01.021

[3] Baeshen, Nabih A., Mohammed N. Baeshen, Abdullah Sheikh, Roop S. Bora, Mohamed Morsi M. Ahmed, Hassan AI Ramadan, Kulvinder Singh Saini, and Elrashdy M. Redwan. “Cell factories for insulin production.” Microbial cell factories 13, no. 1 (2014): 1.

[4] Hallström, Elinor, Annika Carlsson-Kanyama, and Pål Börjesson. “Environmental impact of dietary change: a systematic review.” Journal of Cleaner Production 91 (2015): 1-11.

More From Thats Life [Science]

Dialogue & Discussion