Going green with algae plastic
Like a living bottle, the image showed how the plastic shrunk down. A caption explained that it was the work of an Icelandic product designer named Ari Jónsson. The form seemed to morph from an ordinary bottle shape to a shrunken shell and then the secret behind it was revealed: a tiny water plant, the sludgy, slimy algae that is so unwelcome in swimming pools.
And while this image has made waves online, algae plastic had a more humble beginning. “The idea started in Brittany, France when scientists decided to find a novel way to use the mass of green algae (Ulva) that had washed ashore during a ‘green tide’” said Deborah Robertson-Andersson, a marine biology lecturer from UKZN. The mysterious deflation of the bottle might be the work of a gelatine-like substance called agar which is used in all types of commercial and industrial processes. “Agar can only be used as long as it stays saturated with moisture, otherwise it would shrivel and collapse,” said Environmental consultant, Nicus Durieux. And while the algae bottle depicted is believed to be an agar-based bottle, algae plastic can be formed into a more durable plastic as well. “Depending on the thermal and mechanical processes used in the bio-plastics manufacturing process, you can make the algae do whatever you want,” said Robertson-Andersson, “the algae and its oils are broken down into smaller particles to create granules which are made into bio plastic through heating and mechanical processes,” she said.
While conventional plastics take 200-600 years to break down, algae plastic, like hemp plastic can disintegrate far more quickly. “Algae plastic could biodegrade within 12 weeks,” said Robertson-Andersson. In addition to this, conventional fossil fuel plastic releases Greenhouse gas during production while algae is a “carbon sink,” said Duriex. This means that algae absorbs carbon dioxide, making the tiny plant a welcome addition to any production process. “Each pound (0,45kgs) of algae will consume about two pounds (0,9 kgs) of carbon dioxide,” said Robertson Andersson. Growing algae gets another green light because it does not compete with food crops like other bio diesel or bio oil alternatives that are grown on land although harvesting enough algae may not come naturally. “The biggest limitation of commercial algae production, in terms of seeking a replacement for crude oil derived plastic, is that oil producing species or strains must be cultivated,” said Durieux. Growing algae for agar plastic production is a viable option in South Africa since the right kind of algae is a shore option off the coasts. “Species of commercial red seaweeds are Gracilaria, Gelidium and Pterocladia ,” said Duriex and while theses do occur in South Africa, good sunlight, oxygen, water CO2 levels and temperature are all factors that effect algae growth. However, growing algae quickly enough to produce plastic might be possible since it grows so quickly, reaching maturity, within days or weeks depending on the type of algae.
But, these environmentally friendly alternatives won’t become a reality if consumers aren’t buying it. However, the labour intensive harvesting of seaweed would create jobs in coastal areas that are seeing a job drop on the tail of the reported fish stock slump. “Until we can find something that can compete with crude oil in terms of production cost and won’t impact on our global food production, the best way to reduce the environmental impacts of plastic are to reuse and recycle as much as possible,” said Durieux summing it up with two of the three ‘R’s’ of recycling: reduce, reuse and recycle.