Science

Plastic-eating "super-enzymes": the key to the ecological crisis?

By: Krisha Veera

Once prized for their durability, plastics now clog up oceans and pile up in heaps on land. Plastics take around 450 years to degrade in the ocean and even after this, they only break down into microplastics, remaining harmful to the environment. Hence, when scientists in Japan discovered bacteria that could “eat” plastic, the race to develop the most effective plastic-devouring bacteria began.

The bacterial strain discovered can decompose a type of plastic called polyethylene terephthalate (PET). However, its efficacy isn’t nearly high enough to mitigate the tens of millions of tons of plastic waste that enter the environment every year. To make these naturally-occurring bacteria useful, scientists bioengineered the bacteria and increased its decomposition speed to a matter of weeks. In October 2020, this process was improved further by extracting two enzymes from this bacteria and combining them to produce a “super enzyme.”

The super enzyme combined the PETase and MHETase enzymes, allowing the breakdown of plastic up to six times faster than the previously bioengineered bacteria. The implications of this super enzyme are huge for recycling PET. PET is a type of plastic used in single-use drink bottles, carpets, and clothing, which naturally takes hundreds of years to degrade in the environment. With the super enzyme, it can be broken down into its building blocks in only a few days.

These breakthroughs make it possible to see the super enzymes in industrial-scale facilities, used on piles of landfill-bound plastic or on the mountains that accumulate in oceans and rivers. However, large-scale commercial use of plastic-eating microorganisms is still years away, since their release in the environment could create additional unpredicted issues. Furthermore, the enzymes discovered and bioengineered have only been able to digest one type of plastic—PET. There are several major commercial types of plastic, such as polypropylene, which is used to make containers, and high-density polyethylene, which is used in shampoo bottles and milk jugs.

Additionally, the super enzyme doesn't degrade the plastic back to its core elemental building blocks (such as carbon and hydrogen), it breaks down the plastic into components that companies can reuse to create more plastic. Other concerns include the risk of releasing chemical additives stored in plastic products and the potential unknown side-effects of releasing genetically engineered microorganisms into nature. Hence, the large-scale commercial use of plastic-eating enzymes is still years away.

Apart from the bacteria found by scientists in Japan, several other organisms which can decompose plastic have been found. Scientists have reported a fungus that has been degrading plastic at a waste disposal site in Islamabad, Pakistan. In March 2020, German scientists discovered bacteria strains that could degrade polyurethane plastic while collecting soil from a brittle plastic waste site in Leipzig. Furthermore, tiny wax worms also have the ability to chomp through plastics such as polyethylene using the bacteria in their guts. Mealworms also possess this capability; around 3,0004,000 mealworms can break down a Styrofoam coffee cup in about a week.

Even with the recent discoveries of plastic-eating microorganisms, the fight against plastic pollution remains dependent on switching to reusable alternatives, ensuring that non-recyclable plastic waste ends up in a landfill rather than in the environment, and using biodegradable materials when possible.

Photo: Chokniti Khongchum

Photo: Lucien Wanda

Science

The dangers and unethical practices of animal testing

By: Navam Thind

We’ve all heard of animal testing, right? The harsh practices and experiments that are done on animals to test products for humans. But what actually happens at the laboratories where animals are subjected to cruel operations, and why has animal testing actually increased over the past few years? The term animal testing refers to the procedures performed on live animals for research purposes, and to test the safety of consumer products, such as cosmetics. Some common animal procedures include: exposure to chemicals or drugs, food and water deprivation, and many more. The most common types of animals used in these unethical experiments include mice, rabbits, guinea pigs, hamsters, and monkeys. Animal testing is more common than many might think, since it’s legally required for many of the products that we use. For example, there are 10 000 animals killed for every new pesticide chemical tested. According to the Humane Society International, more than 115 million animals worldwide are used in laboratory experiments every year. In Canada, the number of animals being tested on increased to 5 million in the year 2020.

Despite the growing evidence that it is time for change, many laboratories have relied on animal testing as the default method for decades. It is often argued that because animal experiments have been used for centuries and progress has been made in terms of medicine and consumer products, animal testing must be necessary. New science reviews show that research using animals correlates very poorly to real human patients. In fact, this data demonstrates that animal studies fail to predict real human outcomes in 50-90% of cases. This is mostly because other species rarely suffer from the same diseases that are found in humans. The National Institutes of Health state that 95 out of 100 drugs that pass in animals fail in humans.

Animal testing has, in fact, been increasing over the past few years. According to CBS News, the use of animals in experiments has increased nearly 73% in the past 15 years. This is because many of the animals used in these procedures die, without producing sufficient results. Thus, more and more animals keep getting tested. Most of the animals used in tests, such

Photo: Ricky Khara

as mice, rats and birds aren’t defined as ‘animals’ in the Animal Welfare Act. The Animal Welfare Act is the main law in the US that regulates the treatment of animals in research. Because of this, the use of small animals in testing keeps increasing. Many organizations working to end animal testing, such as PETA, The John Hopkins Center for Alternatives to Animal Testing, and Americans for Medical Progress. Many groups are researching alternatives to testing on animals by running tests using human cells and tissues. For instance, in Brazil and South Korea, it is illegal for a company to conduct animal experimentation if an approach without testing animals is available. Animal experiments are a major part of medical history, but we need to move past testing on animals and turn to quality research and modern technology.

Photo: Matthew Henry

Stress - a hidden friend

By: Varchas Varma

We experience stress every single day. Big things like school, social life, our future, or incredibly minute details in our lives, like remembering an assignment due tomorrow right before you go to bed, all result in stress. But if we endure stress multiple times every day, why haven’t we gotten used to it yet?

Under stress, your body releases the hormone known as adrenaline, a key tool in the process of stress. Your body knows itself better than you do, which means it will always release enough of the adrenaline hormone to make you feel ‘stressed’. It is possible to do certain exercises to reduce these symptoms or even completely avoid them, but that might not be the most beneficial decision in the long run.

Stress is an instinct. Think carefully about why we stress and the symptoms we feel. For example, there is a huge test you’re about to take. Your heart beats faster, your breathing quickens, you feel increasingly anxious, and you are thinking about nothing other than the test. All of these symptoms are, in actuality, pushing your body into a hyper-state. You breathe faster to bring in more oxygen, your heart beats faster to allow your muscles and brain to think and move quicker, and your anxiety heightens your awareness while you focus on the task at hand. With no context as to what stress is, these symptoms may feel detrimental, but they are actually trying to help you.

A study conducted in 2010 had 60 students complete a mock-exam, half of whom were told “People think that feeling anxious while taking a standardized test will make them do poorly,” while the other half were told “recent research suggests that stress doesn’t hurt performance on these tests and can even help performance. People who feel anxious during a test might do better…. If you find yourself feeling anxious, simply remind yourself that your stress could be helping you do well.” This changed mindset in students had a drastic effect on their test scores. Students who viewed stress as a positive process scored much better on the test while those who were told to fear stress scored worse.

For the majority of people, at least in my case, we have been told to suppress our stress or to simply ignore it. However, this attitude does more harm than good.

So what can we do with this newfound mindset? How does viewing stress positively help our lives? Well, let's go back to our previous example about a huge test. Learning how to embrace the symptoms of stress instead of fighting them will help you stay more focused and more awake leading to and during the test, and be better adjusted to the ‘stressful’ environment. In our previous example of remembering an assignment before bed, the adrenaline rush from stress would instantly wake us up. As our heart beats faster and blood rushes into our muscles quicker, it eliminates any fatigue we once had, aiding us in finishing the task at hand.

Stress is an inherent part of our bodily systems. Changing our attitude towards it and embracing its positives can, if done properly, vastly improve our mental and physical health.