A renewable cyclic monoterpene obtained from citrus peel, limonene is widely used as a fra-grance, nutraceutical ingredient, antibacterial, biopesticide, and green extraction solvent. Indus-trial demand largely exceeds supply. After reviewing recent advances in the recovery of limonene from citrus peel and residues with a particular attention to benign-by-design extractive processes, we focus on the latest results in its dehydrogenation to p-cymene via heterogeneous catalysis.

Is the production of the “AnchoisFert” organic fertilizer via the circular economy process based on omega-3 lipid extraction of milled anchovy fillet leftovers with citrus limonene followed by mild drying economically and technically viable? This study answers this question and identifies the main obstacles, chiefly of economic and organizational nature, to be overcome prior to commercialization of this new organic fertilizer. Along with non-variable and proven efficacy, successful competition with conventional organic and inorganic fertilizers requires affordable cost and regular supply. This, inter alia, requires to establish new and mutually beneficial relationship between bioeconomy firms and fish processing companies.

Anchovies are amid the largest fish catch worldwide. The anchovy fillet industry generates a huge amount of biowaste (e.g. fish heads, bones, tails) that can be used for the extraction of several potentially valuable bioproducts including omega-3 lipids. Following the extraction of valued fish oil rich in omega-3, vitamin D₃ and zeaxanthin from anchovy fillet leftovers using biobased limonene in a fully circular process, the solid residue was used as starting substrate for the production of biogas by anaerobic digestion. The results first reported in this study demonstrate good potential energy recovery of the anchovy sludge of about 280 mL_CH4∙g_VS^-1. Due to unbalanced C/N ratio typical of marine biowaste, co-digestion with a carbon rich substrate is recommended.