Plastics production has been continuously growing for over 50 years. Demand of plastics from European converters reached 45 Mt in 2009, from which the main market share (40.1%) of overall demand was packaging. A recent study estimates that 250 kt of plastic are floating adrift in the oceans, representing a direct impact on marine fauna due to its ingestion or by becoming entangled in them. Plastics are also considered as a hazardous waste due to its ability to sorption of pollutants.
Replacing of conventional plastics by bioplastics has been advocated as an approach tht uses renewable biomass as raw material and/or facilitates their degradation at the end of a product lifetime. Microbially produced polyhydroxyalkanoates (PHA) are fully biodegradable biopolyesters that have attracted increasing attention due to its unique characteristic of being biocompatible, compostable thermoplastics and elastomers that can be produced from renewable resources. PHA are suitable for uses like packing material or medical devices. They can be processed into a vast number of products using conventional technologies. Many bacteria use PHA as energy and carbon storage when there is a carbon excess with respect to other nutrient in the medium. Despite the attractive advantages of bioplastic, its production cost cannot yet compete with the cost of petroleum-based plastics. PHA production cost is determined by the price of the carbon source used in the fermentation process and the downstream step. Therefore, the development of fermentation strategies and the search for cheap carbon sources are of special importance.
In the Biogroup, we are evaluating the integration of the production of PHA into first and second generation biorefineries. The production of PHA together with other bioproducts, such as biofuels and high-added value products would increase the economics and productivity of the biorefinery. For this purpose, we have evaluated the production of PHA from biological pretreated wheat straw and stillages coming from cereal-based ethanol plants using the halophilic bacteria Halomonas boliviensis. We have found that Halomonas is a versatile microorganism that is able to produce high PHA content from various carbon sources including volatile fatty acids, mono and disaccharides, starch and cellulose hydrolysates.
Projects
· Unlocking the potential of Sustainable BiodegradabLe Packaging (USABLE Packaging)
European Commission. Horizon 2020 Programme. Call: H2020-BBI-JTI-2018 (2019 - 2021)