Why seaweed may be our next secret weapon in the fight against plastic pollution

Photo credit: Adobe Stock/mivod

Plastic pollution has become an alarming problem all over the world. A 2015 study Posted in Scientific journal predicted that by 2025, around 100 to 250 million tonnes of plastic waste could enter our oceans each year.

The problem also triggered the United Nations (UN) to issue a global resolution to end plastic waste, adopted by representatives of 173 countries.

However, even if all drastic measures were put in place to stop plastic production tomorrow, we would still have around 5 billion tons plastic waste in landfills and the environment.

Research has shown that plastic can disintegrate into microplastics – particles ranging from 1 nanometer (nm) to less than 5 micrometers (mm) – with various shapes, densities, and mechanical and chemical properties.

Due to their small volume and large area, microplastics can absorb pollutantscausing chronic toxicity when consumed and accumulated in organisms.

For decades, scientists have looked to nature to tackle the plastic problem. Combined with global strategic action to slow plastic production, we could prevent future plastic disasters.

Microalgaefor example, are the most promising natural candidate capable of destroying microplastics. It is a single-celled species that exists individually or in chains or groups. Depending on the species, their size can range from a few millimeters to hundreds of micrometers.

Growing microalgae is simple because it does not require fertile soillarge amounts of fresh water and pesticides compared to other aquaculture crops.

Microalgae are also able to grow rapidly. Open pond culture has been one of the oldest and easiest ways to grow microalgae on a large scale. Some people also use photobioreactors – bioreactors used in a closed system to increase the culture of microalgae.

How microalgae work

Interaction between microalgae and plastic can significantly change the properties of the plastic, including its biodegradation, alteration of plastic density and sinking behavior. Additionally, microalgae can take over, congregate and stick to microplastics on their surface, whatever their size.

There are four stages of plastic biodegradation. The first is the attachment of microalgae to plastic surfaces. This triggers the biodegradation process and changes the surface properties.

The second is biodeterioration. Microalgae secrete specific enzymes, essential for the biodegradation of plastic.

The third is the biofragmentation process. At this stage, the plastic material loses its mechanical stability and becomes brittle.

The final stage is the assimilation process, where microbial filaments and water begin to penetrate the plastics, causing the plastic to break down and be used by microorganisms.

Studies have reported successful examples of algae-based plastic biodegradation, particularly for polyethylene (commonly used in fibers for clothing or bottles), low-density polyethylene or LDPE (used in plastic bags). plastic) and bisphenol A or BPA (chemicals to harden plastic). One of these studies calculated a 58.9% decrease in carbon composition in their LDPE sample.

More action is needed

As the largest archipelago country, Indonesia has a sea area of ​​over 6.4 million square kilometers and vast freshwater lakes that have immense potential for growing microalgae.

Microalgae could be a viable solution to the plastic problem in Indonesia – the world’s second largest ocean plastic polluter, according to to a 2015 study.

Further research is essential to further analyzes of the interactions between microalgae and microplastics and their effects to support this initiative. So far, studies of microalgae in Indonesia focus only on its potential as a source of green energy or its ability to become a substitute material for plastic.

To prevent plastic-related disasters, we also need to improve plastic recycling and reuse strategies. Regulations and policies must comply National Marine Debris Action Plan 2018-2015 which highlights Indonesia’s waste management, reducing or substituting plastic use, redesigning plastic products and packaging, doubling plastic waste collection rates, and expanding plastic waste collection facilities. waste disposal.

This article is republished from The conversation under Creative Commons license. Read it original article.

Bryce K. Locke