On a future field trip to Mount Royal, I imagine opening up my lunch box to find a small forest of fried insects flavoured with MSG and curry powder. On the side are some salmon rice balls. Noting I missed some greenery, I grab some grass and sprinkle it onto my rice balls.
As a child, I always dreamed of tasting different types of bark and wild plants. Maybe it鈥檚 just human nature to want to put things into our mouths. While there鈥檚 no safe way for me to consume bark without upsetting my stomach, researchers studying digestion in animals might one day find a way to confer superhuman digestive abilities on people.
In modern farming, there is in adding enzymes such as hydrolases to animal feed to aid digestion. Cattle and pork feed is composed of plant material, the cells of which have cell walls brimming with cellulose. For humans, cellulose would be considered to be fiber because we cannot digest it. Many animals, however, are blessed with bacteria in their gut that produce hydrolases, enzymes, that with the aid of water break fiber down into digestible components. Cellulase, for example, breaks cellulose down into glucose that can then be absorbed into the bloodstream to be used as a nutrient.
While both cows and pigs are capable of digesting these rigid plant cells鈥攃ows being more efficient due to the many bacteria in their multi-chambered stomachs鈥攏evertheless adding cellulases to their feed has been shown to yield benefits such as:
1) A increase in milk production in cows
2) Increased body weight gain in pigs
These benefits alone are impressive enough to turn heads. But now for the interesting part. have found that less might actually be more! In some cases, lower levels of cellulase led to better digestibility than higher doses. Just a bit more enzyme, and poof you have a whole new set of digestive superpowers.
What makes this even more exciting is the growing interest in engineering bacteria that can live in the human gut and produce these enzymes on site. While the cellulase production may be minimal, it may be just right for the anticipated benefits. Those benefits mean deriving more nutrients from plant-based foods and possibly easing hunger in the world.
Genetic engineering of microorganisms to produce specific organic products like enzymes may sound like science fiction, but it is already widely used in the pharmaceutical industry to produce insulin and antibiotics. Most genetic engineering efforts aim to improve the yield of a desired product. This process can be compared to sending a yellow sticky note with 鈥淣OW, MORE!鈥� written on it in an email to our bacterial friends, instructing them to prioritize production. Sometimes we also include a blueprint in the email, so they know exactly what to make. In scientific terms, this means inserting a gene (the blueprint) into a plasmid vector (the email), along with genetic edits (the sticky note) that signal how strongly it should be expressed.
Similar to the beneficial bacteria in yogurt, cellulase producing microorganisms can be engineered to survive in the gut microbiome and help us absorb more nutrients from plant-based products. Moreover, have also found that the gut plays a valuable role in overall health, surprisingly even through a supportive relationship with the brain. In rodents, short chain fatty acids (SCFAs) produced by microbial fermentation of digested plant material have been shown to enhance health. Therefore, cellulase producing microbes have the potential to improve human physical health and reduce food waste by improving digestion.
Although this technology sounds promising, there are still several challenges to consider like the ethics and impact. First, much of the research has been conducted in rodents, so results may not fully translate to humans. Second, because the gut microbiota is complex and essential to health, it is necessary to understand how genetically modified bacteria could impact the native microbial community before introducing them.
While there are still many hurdles to overcome, we may soon be able to snack on grass and bark, thanks to our newly found digestive superpowers. Until then, let鈥檚 not forget to pack some real vegetables in our lunch box!
@ShonaHanaishi
Shona is a third year (U3) Life Science student. He is passionate about understanding the little things that make up our daily lives, and enjoys sharing fun facts that surprise and brighten the days of others.
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