In the framework of a “zero waste” society and economy, the scientific community has witnessed and participated in an auspicious global plan aiming to the valorization of inedible and waste biomass; one of the most abundant and sustainable resources for the production of bio-fuels and bio-chemicals. In this context, the ReWardCHEM project aims to the use of residual biomass (e.g. straws, pruning, peels, mills residues) that are rich in hexose-based polysaccharides (HBP) (i.e. cellulose and/or starch), towards the production of high-added value bio-based chemicals with emphasis on organic acids, in particular gluconic and glucaric, applying innovative catalytic processes. Both acids are produced by the cascade oxidation of glucose and are included in the list of the top 12 ‘hot’ biobased chemicals that are considered as viable alternatives to their fossil-based counterparts. Furthermore, their global demand is predicted to increase the next decade due to their numerous applications in the pharmaceutical and polymer industries.