The project aims to develop a new cost-competitive and environmentally friendly bionanocomposite material based on the combination of a polyhydroxybutyrate (PHB) matrix with new chemical, structure produced by new fermentation culture technology with two types of nanofibres,cellulose whiskers and lignin-based, in order to have a true alternative to engineering materials in two main sectors: household appliances, computers & telecommunications. To fulfil this global objective, current limitations of PHB polymers and their composites will be overcome using a synergic combination of different approaches: •A tailor-made PHB biopolymer structure obtained using new fermentation culture conditions, i.e, by synergic combination of different media and precursor feedings (specific sugar blends) obtained from hydrolyzed bio-mass, being able to select a structure to provide a PHB with enhanced functionalities (improved thermal and chemical properties, cellulose compatibility, processing, higher impact,..) in comparison with commercial ones. •To improve the cost competitiveness of PHB biopolymer by optimization of the fermentation process (increasing yield) and the use of lingo-cellulose biomass and other industrial by-products as fermentation feedstock. It will be no competition with food supply. •Development of cellulose whiskers and lignin nanofibres using enzymatic production routes with new functionalities (antimicrobial, flame retardant and self-assembly) from wood waste. •Compounding of new PHB with a synergic combination of both types of nanofibres and long natural fibres, using the planetary multi-screw extruder for improved nanofibres distribution, reducing thermal degradation,improve matrix-nanofibre interphase and introduction of coupling agents by reactive extrusion. •Development of multilayer structures (co-extrusion and co-injection) in order to obtain multifunctional material properties to improve the final performance of plastic parts in select sectors.