Several different cultivation systems for the production of halophyte biomasses were successfully demonstrated in the AQUACOMBINE project: greenhouse growth optimisation and cultivation, free-land cultivation, hydroponics cultivation, and aquaponics cultivation, and halophyte plant materials were delivered for the pilot and demonstration scale biorefinery trials. The cultivation trials carried out in the AQUACOMBINE project have given new insights into the optimal growing conditions for the four species, optimal harvesting time for the biorefinery biomasses, and the use of Salicornia europaea in aquaponics systems.
For the biorefinery development the following processes were optimized in the first reporting period of the project: phytochemical (polyphenols) extraction and stabilization, green protein extraction, xylo-oligosaccharides (XOS) production from residual biomass fibers, and biogas and biochar from the residual biomass fractions from all processes. In the last reporting period, the biorefinery processes were scaled up. The demonstration-scale multistep cascade extractor was delivered at AAU November 2023 completing the full AQUACOMBINE biorefinery, and the proof-of-concept trials were carried out in November and December 2023. The best cascade combination showed that the amount of total phenolic content was increased with 95 % and the total flavonoid content in the extract was increased approx. 200% compared to traditional Soxhlet extraction. Polyphenol-rich extracts, green protein, and XOS were delivered for the cosmetic production and the fish feeding trials, and several papers were published reporting the bioactives composition of S. ramosissima, T. pannonicum and C. maritimum including antioxidant capacity and inhibition activities against enzymes linked to diseases such as neurodegenerative diseases (e.g. Alzheimer’s disease), hyperpigmentation, type 2 diabetes, obesity, and acne.
A skin cream, face serum, hair shampoo, and body wash were developed with the S. ramosissima extracts, and safety assessment and stability tests were carried out. A cream cheese was formulated with ground S. ramosissima and a yoghurt was formulated with S. ramosissima extract. The products were evaluated in consumer sensory tests with good evaluations. Six experimental diets containing Salicornia biomass/extracts and two control diets were formulated, produced, and used in shrimp (P. vannamei) and European seabass feeding trials. The inclusion of S. ramosissima extracts showed that genoprotection properties play a role the presence of genotoxic challenges, probably promoting a proper activation of DNA repair pathways under challenging scenarios. The fibre residues were successfully used for the production of biogas and biochar at scale-up conditions.
For the aquaponics, a scale-up flexrack unit for turbot aquaculture as well as four aquaponic units (covering 120 square meters) for the cultivation of S. europaea using effluent water from the turbot system, was demonstrated. Along with this, three tanks in the steelhead aquaculture units were stocked with steelhead juveniles and data was produced on the two fish systems.
TEA and LCA were finalised for the AQUACOMBINE processes. For the biorefinery, polyphenol extraction from lignified biomass, protein extraction from green biomass, organosolv process, biogas and biochar production were considered for the capacity of 2000 tons/year biomass input. The estimated total capital investment and production costs amount to €16.9 M and €6.6 M/year respectively. The expected minimum net profit from products (extracts, biochar, heat, and electricity from biogas) is estimated as €10.5 M/year. Also, the sensitivity analysis was made for the different capacities of the biorefinery, and it was found that the biorefinery profit increases with increased capacity, but it is still possible to make a profit for the small capacity (the capacity of 2000 tons/year of biomass).
The AQUACOMBINE project has received a lot of attention in this final period of the project and main dissemination and exploitation achievements include Stakeholder meetings, Scientific Advisory Board meetings, development and establishment of European Saline Farmer Association, the second batch of practice abstracts refined and used for dissemination purposes, Website re-design, developed Roadmap for exploitation, and a Handbook for lessons learned designed and used for dissemination.
