Cascade valorization of olive leaf biomass in CENER BIO2C

Among several developments, at the moment CENER is intensively focused with a consortium of partners on the complete valorization system for olive leaf, based on Smart Dynamic Multi-Valorization-Route Biorefinery for the cascade valorization of the olive leaf biomass according to its physicochemical composition, particularly modulated by specific pretreatments to produce target products for high value sectors: food, feed, health, cosmetic, pharma and chemical industries.

Globally, 4.5 million tons of olive leaves are produced every year by the olive oil industry, a key industry in southern Europe and along the Mediterranean basin. This biomass represents a challenge for both the farmers and the whole olive oil industry since it needs to be removed from the field and olive oil mills to avoid environmental and economic concerns.

In order to complete valorisation of this underexploited raw material, the OLEAF4VALUE project, which is a three-year research and innovation action (RIA) funded by the European Union (H2020 -JTI-BBI), is focused on the development of a complete olive leaf upcycling system, with a consortium composed of sixteen partners: six Research Technology Organisations (RTOs), seven Small and Medium Enterprises (SMEs), and three Large Enterprise (Les), from nine different countries throughout Europe (Germany, Italy, Netherlands, Norway, Portugal, Slovenia, Spain, Switzerland and UK).*

The focus is the cascade valorisation of the olive leaf biomass according to its physicochemical composition, particularly modulated by specific pre-treatments to produce target products. Advanced green extraction and isolation technologies are being used to sequentially separate all fractions and compounds of value, with a zero-waste approach. Enzymatic biotransformation and nanoencapsulation technologies are applied to develop tailor-made prototypes according to end user market needs from high value sectors such as food, feed, health, cosmetic, pharma, and chemical industries.

In further detail, CENER is applying its own developed novel pretreatment technologies for hemicellulose and lignin valorization in exhaust leaves for the separation of XOS (soluble hemicellulose) main stream by acidic/basic pre-treatments, as well as for the reaction and fractionation of lignin main stream to produce antioxidants by thermal oxidative depolymerization continuous process.

So far, exhaust leaves from previous valorizations routes such as polyphenols, triterpenoids  and fermented leaves have been tested with pre-treatment trials for the conversion of hemicellulose and lignin into XOS and bio-aromatics. Preliminary findings were published for the Consortium in the “Intermediate report on the hemicellulose and lignin derivatives main stream and side stream valorisation route-5” (D2.5) last December 2022. CENER is facing the last trials with fermented olive leaves produced by NATAC and INGECOR and final results will be reported next June 2024.

On that sense, in one hand the valorisation of exhausted olive leaves by pre-treatment for hemicellulose hydrolysis in order to produce XOS have been tested as a prebiotic stream by employing different types of microorganisms showing a positive growth confirming the substrates are a prebiotic source.

On the other hand, the antioxidants production from lignin enriched fractions, exhausted solids from the cascade valorization approach, shown an activity similar to a natural extract such as rosemary extract.

With this novel pretreatment technologies for hemicellulose and lignin valorization, on top of research starting at low TRLs, CENER aims to overcome one of the key challenges in the process of developing new bioproducts resulting from the transition period in which a technology under development is envisaged as promising, but too new to validate its commercial potential.

*NATAC BIOTECH SL (NATAC), OLEICOLA EL TEJAR NUESTRA SENORA DEARACELI S COOP AND (OET), INGECOR AGROFORESTAL SL (IGC), INNORENEW COE CENTER ODLICNOSTI ZA RAZISKAVE IN INOVACIJE NA PODROCJU OBNOVLJIVIH MATERIALOV IN ZDRAVEGA BIVANJSKEGA OKOLJA (INNO), FUNDACION CENER (CENER), INSTITUTO POLITECNICO DE BRAGANCA (IPB), BIOCHEMIZE SL (BCZ), UNIVERSITA DEGLI STUDI DI FIRENZE (UNIFI), NIZO FOOD RESEARCH BV (NIZO), MARTIN-LUTHER-UNIVERSITAET HALLE-WITTENBERG (MLU), HAVFORSKNINGSINSTITUTTET (IMR), MIBELLE AG (MBL), EURIZON SL (Innovarum), ZERO EMISSIONS ENGINEERING BV (Zero-E), NNFCC LIMITED (NNFCC), MOWI FEED AS (MOWI).