Sustainable and biodegradable packaging created from algae and bacteria grown on a new feedstock is the end goal of a research project led by The University of Sheffield.
In the first phase of this project, the researchers showed that specific strains of algae and bacteria can be grown on a type of wastewater called leachate using sunlight.
Now in the second phase of this project - having secured a £1.64m grant from the Engineering and Physical Science Research Council (EPSRC) - the researchers are aiming to optimise the production of cellulose and a polymer called polyhydroxyalkanoate (PHA) in the cells of the algae and bacteria, respectively.
As part of this, the researchers have recently submitted a research paper outlining a new screening method that enables efficient comparison of thousands of combinations of bacteria and algae.
After the microbes have been grown on the industrial leachate, the cellulose and PHA will be extracted by a team led by Professor Tom Welton at Imperial College London. They will use novel ionic liquids and look to recycle these to further improve the environmental benefits of the system.
The biopolymers will be turned into film coatings by Dr. Chaoying Wan, based in the Warwick Manufacturing Group, for uses such as packaging. This packaging could then be used by many industries, including the leachate producer itself for packaging plants and compost etc.
For this specific project, the researchers have sourced the leachate from one of the biggest horticulture companies in the UK, Freeland Horticulture.
Using the new bio-based packaging would allow the company a more sustainable alternative to petroleum-based plastic packaging with compostable capability, while helping to ‘recycle’ its waste into a useful product.
This comes in the context of the increasing need for sustainability across all industries, with a phasing out of single use petroleum-based plastic packaging often discussed as part of the solution.
Indeed, microalgal cellulose also has good barriers to moisture and oxygen, and so can be a good alternative to using plastics in food packaging - in fact it has many possible future uses, and the project is partnered by Unilever for commercial testing.
This is not the researcher’s first project in this area, having previously worked with a number of different companies, but this is the first instance they’ve looked at the entire process in one project.
There are challenges, however, including optimising cultivation to enhance biopolymer levels in the cells whilst the cost of the downstream process is another factor to consider. Therefore, Professor Sol Brown is also part of the project and will develop a techno economic model of the process.
"I’m really chuffed to have such a strong team working on this project, and to be showcasing how defined cultures of algae and bacteria can be used to convert waste effluents from being an environmental burden into a rich source of resources.
"It’s been 8 years since we initially started looking at how to create synthetic microbial consortia for industry, with quite a few upturned eyebrows on the way! And here we are, taking it several steps further in one project.
"This is just one example of how future manufacturing can be circular, rather than the “cradle to grave” options that dominate now. And let’s face it, the opportunities to recover resources from our waste are endless.”
Dr Jagroop Pandhal
Lead Researcher