Author Archives: rebecca yang

Breaking Down Plastic, One Worm at a Time

A 2022 study by Sanluis-Verdes et al. has found that wax worm saliva is able to break down plastic in just a few hours.

The researchers collected saliva from Galleria mellonella worms and applied it to polyethylene (PE) films. After a few hours, the films had visibly deteriorated and analysis of the films determined that the plastic had oxidized and released additives, evidence that it had degraded.

Credit: Catherine Sheila

Generally, plastics require decades or even centuries to completely degrade through natural exposure to the environment. Because of humanity’s high consumption of plastic, simply dumping them in landfills or waterways only leads to an accumulation that smothers habitats and leaks toxic substances into the soil and water.

This makes finding a safe and quick way of breaking down plastic crucial for sustainable waste management.

Scientists in recent years have been particularly interested in biodegradation, in which naturally-produced enzymes from bacteria, fungi, or animals are used to decompose plastic.

However, scientists have only identified a handful of enzymes that are capable of this, and these enzymes still require years to degrade plastic. They are unable to accomplish the first step of degradation – oxidizing the polymer – and still rely on exposure to UV light and other environmental factors to do it, which usually takes years.

Currently known process of plastic degradation. Credit: Rebecca Yang

Sanluis-Verdes et al.’s experiment demonstrated that the enzymes in wax worm saliva are in fact able to accomplish this crucial step under normal physiological conditions – room temperature, neutral pH, typical background levels of UV – in just a few hours rather than years. The researchers identified an increased presence of ketones in the PE after only applying the saliva a few times, proof that it had been oxidized by the enzymes alone.

The researchers also tried to identify the enzymes responsible. They were able to pick out two enzymes in the saliva that had a significant effect on PE degradation. Until now, it was believed that bacteria in the gut of wax worms were primarily responsible for plastic degradation, but this discovery indicated that it was the wax worms themselves that oxidized and broke down PE enough for it to then be completely decomposed by bacteria. The researchers also noted that the two enzymes were functionally different from known bacterial enzymes. This suggests that there may be other methods of biodegradation than what is currently known for bacteria.

The exact mechanism will require further studies to determine. If this can be identified and if the enzymes involved can be easily extracted or mass produced, using the enzymes found in wax worms may become a feasible way to naturally and quickly manage plastic waste.

A Breakthrough in Nuclear Fusion

On December 5th 2022, scientists at the Lawrence Livermore National Laboratory (LLNL) in the United States successfully created the reaction that powers the sun – nuclear fusion ignition – for the first time in human history.

The announcement was made by the US Department of Energy on December 13th. Described as a “historic, first-of-its-kind” achievement, the event has excited the scientific community because of its potential as a clean energy source.

Inside the LLNL’s National Ignition Facility, where the experiment took place. Credit: LLNL

To achieve ignition, the scientists had constructed “the world’s most energetic laser”, consisting of 192 powerful laser beams. This laser was used on a small canister containing the compounds deuterium and tritium, causing the compounds to fuse together. The reaction generated 3.15 megajoules of energy from an input of 2.05 megajoules, a markup of 54%.

After over 60 years since researchers first began to study nuclear fusion, this result finally proved that controlled fusion that produces more energy than it consumes is possible.

Depiction of fusion: deuterium(D) and tritium(T) fuse to form the larger Helium(He) and release energy. Credit: US Department of Energy

Nuclear fusion is the process that allows the Sun to emit vast amounts of energy in the form of light and heat. It involves the joining of two atoms of a lighter element to form a heavier one, releasing energy in the process.

Compared to nuclear fission, which is how nuclear power plants generate energy, fusion is much more powerful. It is also much cleaner as it does not produce radioactive materials as a byproduct.

Because of this, many believe that nuclear fusion is a promising avenue for sustainable and eco-friendly energy in the future. However, there is still a long way to go until fusion can be viable for commercial use.

When asked to comment on the time needed, Kim Budil, the director of the LLNL, stated that “It’s probably two or three decades. Scaling from where we are today to what you would require for a power-generating plant is a pretty significant challenge.”

Director Kim Budil at the announcement of the achievement of ignition on December 13th, 2022. Credit: Mary Calvert/REUTERS

For the 8000 engineers, physicists, and chemists at the LLNL, this event is just the first step. Researchers will have to find ways to conduct nuclear fusion that are faster and cheaper, while also generating much more power. According to Budil, “What we need now is a scientific and investment strategy that allows us to make progress on all of these fronts simultaneously… [because] we need gain of a few hundred [megajoules] to make an energy system.”

Despite the many challenges ahead, Tim Luce, one of the leaders of the international fusion research project ITER, remains hopeful. “A result like this will bring increased interest in the progress of all types of fusion, so it should have a positive impact on fusion research in general,” he states.

A Breakthrough in Nuclear Fusion

Announced by the US Department of Energy on December 13th, this “historic, first-of-its-kind” achievement has excited the scientific community because of its potential as a clean energy source.

Inside the LLNL’s National Ignition Facility, where the experiment took place. Credit: LLNL

To achieve fusion ignition, the scientists had constructed “the world’s most energetic laser”, consisting of 192 laser beams, and aimed it at a small canister containing the compounds deuterium and tritium. They were able to generate 3.15 megajoules of energy from an input of 2.05 megajoules, a markup of 54%.

This result – more than 60 years after researchers first began to study fusion – proved that controlled nuclear fusion that produces more energy than it consumes is possible.

Depiction of fusion: deuterium(D) and tritium(T) fuse to form the larger Helium(He) and release energy. Credit: US Department of Energy

Nuclear fusion – the process that allows the Sun to emit vast amounts of energy in the form of light and heat – involves the joining of two atoms of a lighter element to form a heavier one, and in the process releases a lot of energy. Compared to nuclear fission, which is how nuclear power plants generate energy, fusion is much more powerful and also much cleaner as it does not produce radioactive materials as a byproduct.

For these reasons many believe that nuclear fusion is a promising avenue for sustainable and eco-friendly energy in the future.

However, there is still a long way to go until fusion could be viable for commercial use. When asked to comment on the time needed, Kim Budil, the director of the LLNL, stated that “It’s probably two or three decades. Scaling from where we are today to what you would require for a power-generating plant is a pretty significant challenge.”

Director Kim Budil announcing the achievement of fusion ignition in December 2022. Credit: Mary Calvert/REUTERS

Moving forward, the over 8,000 engineers, physicists, and chemists at the LLNL and researchers worldwide will have to find ways to conduct fusion ignition more quickly and cheaply, while also generating much more power. According to Budil, “What we need now is a scientific and investment strategy that allows us to make progress on all of these fronts simultaneously… [because] we need gain of a few hundred to make an energy system.”

~ Rebecca Yang