The Adriatic Sea case will develop a biorefinery fed by wastes from mollusk and fish industries. The goal of this refinery is to obtain protein hydrolysates for plant biostimulation, nitrogenous fertiliser (chitin), biochar-compost composite, and soil liming agent. To this aim, enzymatic hydrolysis, chitin extraction, composting and pyrolysis will be investigated at lab- and pilot-scale.

The waste material is recovered from local industries of Ancona (Italy), such as Co.Pe.Mo. Cooperative Company, considered as a point of reference for all Italian fishing cooperatives. They sell shellfish species from the Marche Region such as mussels, clams, and murex. From their activities, they produce around 500 t·y-1 of mollusk wastes. Also Ittica del Conero Soc. Coop. has been operating for several years both in the marketing and processing of fish products from the Adriatic sea (tub gurnard, monkfish, hake, salmon, gilthead, cuttlefish, etc) and disposes of around 80 tons of by-products (viscera, bones, heads, etc) every year.

Mussel raw waste

From previous characterisations, it was found that wastes from mollusks consist of 20% of organic material (residual meat) and 80% of shells. Shells mainly are composed of  of inorganic material and they are rich in CaCO3 that will be used as a liming agent. This type of recovery would certainly be of interest, considering that the European median pH is 5.8 for Ap soil (0-20 cm topsoil) (Fabian et al., 2014). The organic part, together with the fish wastes, are rich in protein (more than 50% on dry basis) and will be used to obtain: i) protein hydrolysates through enzymatic extraction; ii) compost and biochar from the solid residue of the hydrolysis step. Chitin will be obtained from crustacean shells.

These products will be tested on site to analyse their quality and properties as fertilisers. The Adriatic case will also aim at the most efficient and profitable biorefinery scheme for fertiliser production in terms of economic revenues and environmental impacts.

Protein hydrolisates