Current methods of growing bacteria in large fermenters to produce high quantities of bioplastics are expensive because glucose is used as a starting material.
The Polyhydroxyalkanoate (PHA) group of polyesters is synthesized by bacteria as an energy source when their carbon supply is plentiful.
Poly 3-hydroxybutyrate (PHB) is the most commonly produced polymer but it is expensive because glucose is used as a starting material for the bacteria to produce the PHB.
Improved quality of PHB combined with low production costs would enable it to be used more widely used and compete with petroleum-based plastics.
Use as a starting material
The University of Wolverhampton researchers found waste cooking oil as a starting material reduced production costs and produced more PHB.
The bacterium Ralstonia eutropha H16 grew better in the oil over 48 hours and produced three times more PHB than current glucose methods, the UK-based team found.
Dr Iza Radecka, senior lecturer in microbiology at the University of Wolverhampton, told FoodProductionDaily.com using waste cooking oil would also reduce environmental contamination.
“Seeing all the food shops with oils that can be collected instead of the small shops where it is dumped in the drain, we wondered if we could use it and get a good result.
“We are reducing pollution and getting plastic to find a cheaper source that produces the best yield and material properties.
“We also looked at rape seed oil which is the common oil in the UK and olive oils but this was only preliminary data and needs more work.”
Scale-up
The next challenge is to do scale-up experiments, to enable the manufacture of bioplastics on an industrial level.
“To get oil from a shop to do lab scale experiments to industrial scale demand depends on what it will be produced for. You might only need a contract with one or two restaurants.
“Good quality polymers used for environmental applications are still more expensive but biodegradeable materials are environmentally friendly.
“We will try different organisms in yield and more materials to see the results in the same timeframe to see if we get more polymers.
“There has been interest already but it depends where it is from as the technology needs to be close to where you collect the oil to minimise transport costs for the local environment.”