ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Valorisation to biogas of macroalgal waste streams: a circular approach to bioproducts and bioenergy in Ireland

Silvia Tedesco and Joseph Stokes

Faculty of Science and Engineering, School of Mechanical Engineering, Manchester Metropolitan University, Manchester, UK

E-mail: silvia.tedesco3@mail.dcu.ie

Abstract: Seaweeds (macroalgae) have been recently attracting more and more interest as a third generation feedstock for bioenergy and biofuels. However, several barriers impede the deployment of competitive seaweed-based energy. The high cost associated to seaweed farming and harvesting, as well as their seasonal availability and biochemical composition currently make macroalgae exploitation too expensive for energy production only. Recent studies have indicated a possible solution to aforementioned challenges may lay in seaweed integrated biorefinery, in which a bioenergy and/or biofuel production step ends an extractions cascade of high-value bioproducts. This results in the double benefit of producing renewable energy while adopting a zero waste approach, as fostered by recent EU societal challenges within the context of the Circular Economy development. This study investigates the biogas potential of residues from six indigenous Irish seaweed species while discussing related issues experienced during fermentation. It was found that Laminaria and Fucus spp. are the most promising seaweed species for biogas production following biorefinery extractions producing 187–195 mL CH₄ gVS⁻¹ and about 100 mL CH₄ gVS⁻¹ , respectively, exhibiting overall actual yields close to raw un-extracted seaweed.

Keywords: Integrated biorefinery; Macroalgae; Methane; Biogas; Anaerobic digestion; Algal residues

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-016-0005-7

Chemical Papers 71 (4) 721–728 (2017)