Macroalgae (seaweeds) represent an emerging resource for food and the production of commodity and specialty chemicals. In this study, a single-step microwave process was used to depolymerise a range of macroalgae native to the United Kingdom, producing a growth medium suitable for microbial fermentation. The medium contained a range of mono-and polysaccharides as well as macro-and micronutrients that could be metabolised by the oleaginous yeast Metschnikowia pulcherrima. Among twelve macroalgae species, the brown seaweeds exhibited the highest fermentation potential, especially the kelp Saccharina latissima. Applying a portfolio of ten native M. pulcherrima strains, yeast growth kinetics, as well as production of lipids and 2-phenylethanol were examined, with productivity and growth rate being strain dependent. On the 2 L scale, 6.9 g L −1 yeast biomassa yield of 0.14 g g −1 with respect to the supplied macroalgaecontaining 37.2% (w/w) lipid was achieved through utilisation of the proteins, mono-and polysaccharides from S. latissima, with no additional enzymes. In addition, the yeast degraded a range of fermentation inhibitors released upon microwave processing at high temperatures and long holding times. As macroalgae can be cultured to food grade, this system offers a novel, potentially low-cost route to edible microbial oils as well as a renewable feedstock for oleochemicals.

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Bilberry presscake, a byproduct from juice production, contains abundant polysaccharides that can be recovered by thermal treatment. In this research, microwave hydrolysis and extraction were carried out using only water as the processing medium, thus ensuring all products (mainly saccharides) are suitable for food grade status applications. This research aims to propose an approach to fulfill multiple chemicals recovery, including anthocyanins, saccharides, proteins, and even inorganic salts. Statistical analysis suggested the conversion of bilberry presscake was accurately predictable (R 2 of 0.986) from conditions. Of the variables temperature, holding time, and solid content, the solid content affects conversion most significantly. A 30 min microwave hydrolysis gives mono-/disaccharides with a high total yield of 24.9%, which is more than three times the yield of a 24 h Soxhlet extraction (7.1%). The yield of rhamnose is particularly high (10.8%), most likely as a result of pectin degradation on microwave irradiation. In addition to the lab scale research, pilot scale microwave extractions are carried out with high conversion (especially glucose 4.4%, xylose 4.0%, and pectin 6.3%), suggesting the feasibility of low-temperature (95 °C) microwave hydrolysis of bilberry presscake for industrial application. With this preliminary study, it is believed microwave hydrolysis offers an efficient and green approach to convert bilberry presscake into value-added products for food industry and biorefinery.

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