FROM AGRI-FOOD WASTE TO HIGH-VALUE COMPOUNDS VIA GREEN TECHNOLOGY APPROACHES

In the framework of sustainable biocatalysis and circular bioeconomy, this thesis explores the development of innova:ve enzyma:c strategies for the valoriza:on of agri-food by- products into high-value compounds. Four complementary approaches were pursued, each focusing on process intensifica:on, enzyme engineering, and biocatalyst immobiliza:on to maximize efficiency, scalability, and environmental sustainability. First, a co-immobilized mul:-enzyme system combining a commercial α-rhamnosidase and an extremophilic β-glycosidase was implemented for the efficient hydrolysis of citrus ru:nosyl flavonoids, achieving >99% conversion in con:nuous flow under zero-waste condi:ons. Second, soybean glycosides were converted into bioac:ve aglycones and lipophilized deriva:ves through a dual strategy involving hydroly:c and esterifica:on reac:ons under flow, thus improving their physicochemical proper:es for applica:ons in food, pharmaceu:cal, and cosme:c sectors. Third, an integrated process was designed for the recovery of phlore:n from apple pomace, employing an extremophilic glycosidase immobilized on bacterial cellulose films, where both substrate and support were derived from the same biomass, reinforcing the concept of feedstock circularity. Finally, a self-sufficient biocatalyst combining an ene reductase and a glucose dehydrogenase was developed for the selec:ve bioreduc:on of cinnamaldehyde, achieving high conversion and opera:onal stability under con:nuous flow, with in situ NADH regenera:on. Overall, this research provides new insights into the exploita:on of extremophilic enzymes, immobiliza:on strategies, and flow biocatalysis for the sustainable produc:on of bioac:ve molecules, highligh:ng their poten:al industrial relevance in the food, cosme:c, and pharmaceu:cal sectors.