Thermomechanochemical (TMC) fractionation by twin-screw extrusion is a versatile and compact process, working at low liquid/solid ratios and able to provide simultaneously solid and liquid fractions. The use of TMC process for fertilizers production from fish by-products is an innovative approach which makes it possible to recover not only fertilizers (proteic fractions) but also highly valuable lipids to reach a Zero-waste process. TMC process has been developed during the Sea2Land project to transform fish byproducts in the presence of enzymes into bio-based fertilizers (BBF).
The process scheme implemented in the Atlantic Area includes the following technological units:
(i) Grinding technologies, (ii) Continuous TMC fractionation by twin-screw extrusion / Enzymatic Hydrolysis, (iii) Downstream processing (separation technologies, concentration).
All these technologies are combined to recover products with agronomic value and to find a specific valorization for lipids. Trials were achieved using an Evolum HT53 (Clextral) at a feeding rate of 150-200 kg/hr in by-product i.e. heads and fishbones from Steelhead truit. Working at 200 kg/h (65 kg/hr DM), the complete process provides 89 kg/hr solid BBF (25 kg/h DM ; 57% Proteins/DM), 129 kg/hr aqueous proteic hydrolysate (16 kg/h DM ; 61% Proteins/DM) and 24 kg/hr lipids.
Further information: “Extrusion” in Green Food Processing Techniques: Preservation, Transformation and Extraction, Publisher:
Elsevier (2019) DOI: 10.1016/B978-0-12-815353-6.00010-0
“Twin-Screw Extrusion: A Key Technology for the Biorefinery” in Biomass Extrusion and Reaction Technologies:
Principles to Practices and Future Potential, ACS Symposium Series (2018) / DOI: 10.1021/bk-2018-1304.ch002
Fig.1: Example of extrusion screw profile
Fig 2: Evolum HT53 (Clextral) twin screw extruder
Authors: Candy Laure & Raynaud Christine / CATAR
– Download this practice abstract –