Improving sustainability of fruit and vegetable processing industry by sub-product transformation

Few years ago, the prices of bulk agricultural raw materials such as wheat, rice or corn have been low because of increasing agricultural yields. This tendency has drastically changed, with competition between biomass for food vs for chemicals or biofuels, becoming a societal issue. According to OECD/FAO the demand for agricultural products is expected to remain firm and crop prices to remain above pre-2008 period. On the other hand up to 25% of fruit and vegetable production is lost or wasted during agriculture and post-harvest activities in Europe. Therefore new approaches are needed to reduce the environmental impact of waste and to produce feedstock's for industry. The implementation of the innovative cascading concept of the European project TRANSBIO for valorisation of sub-products from fruit and vegetable processing industry will improve sustainability of fruit and vegetable production as well as reduce competition between biomass for food vs industrial applications. TRANSBIO characterized and selected appropriate sub-products followed by appropriate pre-treatment and hydrolysis strategies to produce value-added compounds such as food ingredient and platform chemical succinic acid, biopolymer polyhydroxybutyrate (PHB) and enzymes for detergents. TRANSBIO investigated three fermentation strategies; submerged fermentation (bacteria, yeasts) and solid state fermentation (filamentous fungi). Molecular screening procedures for selection of PHB producing bacterial candidate strains were established and PHB production on sub-product hydrolysates was implemented. From by-products 692 yeast isolates could be obtained, including two yeasts able to produce higher amounts of succinic acid without any fermentation optimization. Afterwards fermentation optimization and down-stream processing implementation took place. Solid state fermentation using filamentous fungi could be implemented and enzymes for detergents obtained. Potential of by-products for biogas production could be proven.