Jessica M. M. Adams

Oat β‐glucan provides health‐benefitting properties, with the ratio of subunit trimers to tetramers the main identified molecular difference between this and other grain‐derived β‐glucans. This ratio change causes alterations in the viscosity and gelling potential of the β‐glucan, which in turn affects cholesterol uptake and conversion. This study compares both the physical variables (grain dry weight, width, length) and the ratio and total yield of trimer and tetramer units in developing winter oat (Mascani) grain over two harvest years. Results found the grain weights and widths correlated through the development stages, with length increasing earlier in the development, matching developmental studies in wheat grains. Within the total β‐glucan fraction, the yield followed the trend for grain weight, with the β‐glucan ratio between the composite subunits highly conserved from the beginning of grain formation. β‐Glucan yields were shown not to differ between grains taken from locations across the whorls of the panicle or between the grain types (primary or secondary) within the spikelets, showing composition consistency despite developmental differences. To widen the significance of this work, the yields and ratios of β‐glucan trimer and tetramer were also assessed in 46 different mature oat grain varieties (excluding Mascani). These were found to have a reduced trimer:tetramer ratio correlation ( R ² = 0.84; in Mascani‐only studies R ² = 0.99–1), showing limited diversity between accessions. All spring oat varieties had a lower trimer:tetramer ratio than seen in the Mascani grain initial studies, a positive breeding attribute. A further correlation was seen between trimer:tetramer ratios, grain size and nitrogen, with lower β‐glucan ratios associated with larger grains and lower nitrogen content. Collectively, findings from this study identify useful trait variation for future breeding programme selection considering enhanced health benefits.

Marine macroalgae, microalgae, and associated microorganisms are increasingly recognised as valuable sources of bioactive compounds with applications across biotechnology and health. The environmental and ecological conditions they inhabit shape their metabolite diversity, leading to the production of high-value compounds such as sulphated polysaccharides, lipids, pigments, phenolics, and peptides. These compounds exhibit conserved biological activities that underpin potent antioxidant, anti-inflammatory, cytotoxic, and pro-regenerative effects with strong potential for translation. Although external factors drive rich metabolite diversity, continual variation can also lead to translational constraints including heavy-metal accumulation, inconsistency in extract composition, and regulatory complexity. This review examines the environmental drivers of metabolite diversity and the functional potential of bioactives derived from marine algae. We focus on their translational application within four areas of growing interest: nutraceuticals, cosmetics, regenerative medicine, and oncology, where emerging evidence suggests their promise as next-generation bioactive ingredients and therapeutic leads. In addition, insights from Irish and Welsh Small and Medium Enterprises (SMEs) are collated to identify key bottlenecks in commercialisation and the requirements for effective marine biodiscovery pipelines. We consider the importance of controlled cultivation, standardised analytics, preclinical testing platforms, and collaborative innovation ecosystems and highlight the need for coordinated scientific, technical, and regulatory advances to unlock the full translational potential of marine-derived compounds.

Integrating hydrothermal carbonization (HTC) and anaerobic digestion (AD) has the potential to improve energy conversion efficiency (ECE) of biomass with low energy density and high moisture content. This study aims to assess the influence of alkali metals and chlorides by comparing seawater and distilled water as a HTC reactant medium, treating Fucus serratus across a range of processing temperatures (150 °C, 200 °C and 250 °C). All HTC-AD integration options improved ECE of F. serratus compared to AD alone. ECE of F. serratus was similar across temperatures of 150 °C (84–88%) and 200 °C (75–77%) regardless of seawater or distilled water usage. However, HTC processing at 250 °C yielded a greater ECE from F. serratus using distilled water (78%), compared to seawater (57%), due to a higher hydrochar yield and biomethane generation from the process water. Higher HTC processing temperatures significantly reduced slagging and fouling propensity of hydrochars by selectively removing problematic alkali metals. This creates a compromise between process energetics and favourability of hydrochar properties in large-scale conversion systems. Overall, HTC of F. serratus in seawater at 250 °C produces hydrochar suitable for combustion, process water that generates biomethane during AD (168.4 mL CH₄/g COD) and a net energy-positive process (energy return on energy investment EROI = 1.53).

Macroalgal extracts offer an alternative option to increase crop yields and plant performance whilst reducing reliance on inorganic chemical fertilisers. Macroalgae have high concentrations of bioactive compounds capable of enhancing crop growth, stress tolerance and pest resistance. This study investigated whether seasonal variation in the chemical composition of three brown seaweeds Ascophyllum nodosum , Fucus serratus and Fucus vesiculosus affected plant growth in Arabidopsis thaliana , Beta vulgaris and Lactuca sativa through different extract concentrations. Crops were treated with 1:20, 1:50 and 1:100 dilutions from macroalgal extracts and compared to controls tap water, deionised water and one commercial macroalgae-based fertiliser made from A. nodosum . Dry weight assessment results revealed that moderately diluted dosages had better effects on plant growth than concentrated dosages, showing that the most suitable concentrations of all macroalgae extracts are 1:50 for Arabidopsis ; no trend was detected in B. vulgaris or L. sativa growth. Overall, there were peaks of increased plant growth when treated with extracts harvested in June and August, which correlates with fertility peaks in commercial brown macroalgae in the wild. These results suggest that the optimal harvest for A. nodosum , F. serratus and F. vesiculosus for plant stimulant products should occur between May and August at sustainable harvest levels. Soil respirometry trials using the extracts showed no differences in CO ₂ fluxes between the macroalgal species, different harvesting seasons, or correlation with plant biomass. It is therefore likely that macroalgal extracts impact the plant directly and produce minor impact on soil microbiota. Thus, these results support the use of macroalgal fertilizers as a low-cost and environmentally friendly alternative to chemical fertilisers.

Ulvan is a green macroalgal cell wall polysaccharide that has tremendous potential for valorisation due to its unique composition of sulphated rhamnose, glucuronic acid, iduronic acid and xylose. Several potential applications such as production of biofuels, bioplastics and other value-added products necessitate the breakdown of the polysaccharide to oligomers or monomers. Research on ulvan saccharifying enzymes has been continually increasing over the last decade, with the increasing focus on valorisation of seaweed biomass for a biobased economy. Lyases are the first of several enzymes that are involved in saccharifying the polysaccharide and several ulvan lyases have been structurally and biochemically characterised to enable their effective use in the valorisation processes. This study investigates the whole genome of Vibrio sp. FNV38, an ulvan metabolising organism and biochemical characteristics of a PL24 ulvan lyase that it possesses. The genome of Vibrio sp. FNV38 has a diverse CAZy profile with several genes involved in the metabolism of ulvan, cellulose, agar, and alginate. The enzyme exhibits optimal activity at pH 8.5 in 100 mM Tris–HCl buffer and 30 °C. However, its thermal stability is poor with significant loss of activity after 2 h of incubation at temperatures above 25 °C. Breakdown product analysis reveals that the enzyme depolymerised the polysaccharide predominantly to disaccharides and tetrasaccharides.

Intensive agricultural practices and poor management of organic waste have adverse effects on aquatic ecosystems, where excessive macroalgal proliferation can occur to form ‘green tides’, with negative environmental, ecological and socioeconomic impacts. One novel method for converting a problematic material into a valuable resource is to use excess algal biomass as a feedstock for biochar production. With a high elemental composition, such a resource might be suitable to redress soil deficiencies and to ameliorate soil fertility. Green macroalgae from the Ulva genus, in bladed (predominantly U. rigida), tubular (predominantly U. prolifera) and mixed morphological (U. rigida and U. prolifera) phenotypes, were used to produce biochars. A pot trial within a controlled-environment chamber was carried out to determine the effects of amending high- and low-fertilizer compost with algal biochars (applied at 0, 0.5, 1, 2 and 5% w/w) on the growth rate of Arabidopsis thaliana. A commercial wood-based biochar was used under similar treatments as a control. Weekly imaging and final harvest weights provided additional growth data; composition data including ultimate and proximate analyses, pH, Brunauer–Emmett–Teller (BET) surface area and hydropyrolysis of the dried macroalgae and algal biochars were also conducted. Significant enhanced growth in seedlings grown with biochar amendment were not observed in high- or low-fertilizer compost, and the addition of algal biochars at 5% w/w to high-fertilizer soil significantly reduced plant growth. Elemental analysis revealed that the algal biochars contained high quantities of alkaline elements including sodium. It was hypothesised that salinity was the primary factor affecting plant growth at higher biochar application rates, despite the algae being sourced from an estuarine environment. Biochar provenance and composition is highly significant: using the catch-all term ‘biochar’ ignores both the range of materials and composition that could be used to create it and its subsequent impact within the soil. HIGHLIGHTS Graphical Abstract