Fanny Lalegerie1, and Dagmar B. Stengel1
1Botany and Plant Science, School of Natural Sciences, Ryan Institute for Environmental, Marine and Energy Research, University of Galway, Galway, Ireland
Marine macroalgae are highly diversified organisms whose productivity and associated chemical composition vary greatly according to environmental fluctuations. Seaweed physiology is impacted by gradients in abiotic factors at different spatial (i.e. from few centimeters to several kilometers) and temporal (e.g. tidal, seasonal, inter-annual) scales, and responses are additionally subjected to climate change. This complex natural variability needs to be considered from a valorisation perspective since steady biomass production and composition are key in ensuring sustainable exploitation of natural populations, without modifying the key ecosystem services that macroalgae provide. A specific objective of the BlueBio Cofund project MINERVA (‘Marine Innovation using Novel Enzymes for waste Reduction and Valorisation of Algal Biomass’) is thus to assess and optimise natural seaweed biomass for subsequent integration into efficient biorefinery processes across diverse industrial sectors. To this end, seasonal screening of total phenolic content (TPC), pigment composition and antioxidant capacity of Irish macroalgal species was undertaken to identify local biomass with highest potential. Methodological comparisons were carried out to identify and apply most relevant protocols for the assessment of natural variability. In addition, for the commercial species Ascophyllum nodosum (Phaeophyceae, Ochrophyta), temperature responses were evaluated by Pulse-Amplitude Modulated (PAM) chlorophyll fluorescence, CO2-absorption and O2-evolution, and related to antioxidant capacities. Results highlight the effect of environmental change on algal physiology and associated chemical composition for specific high-value applications, and particularly the effect of climate change in the context of long-term sustainable exploitation of macroalgae.