Ensiling of Saccharina latissima and Laminaria digitata with organic acid additives

Other conference contribution, 2016

Seaweeds are a promising source of biomass to provide food, fuels and chemicals in a sustainable future. However, some issues for a biorefinery are that its composition as well as availability varies seasonally and a fresh source cannot be provided all year around. To secure a steady biomass supply the harvest has to be preserved and today drying (especially sun-drying) is commonly used for seaweeds in the carrageenan industry. In colder climates, however, relying on sun-drying could be more problematic and energy intensive drying utilizing hot air is the alternative. An alternative method is ensiling, which is common in agriculture for preserving animal feed. Ensiling is not well researched for seaweeds, though it is receiving more and more attention. It offers a low energy alternative for preservation that relies on acidification by lactic acid bacteria in an anaerobic environment efficiently hampering growth of unwanted microbes. To ensure that the microbial community is beneficial for a good ensiling process additives can be used e.g. inoculum, organic acids, enzymes and sugars. In this study, six different organic acids have been tested at three different concentrations to investigate them as potential additives for ensiling of Saccharina latissima and Laminaria digitata. The content of protein and the monosaccharide profile in the biomass has been analysed before and after 90 days of ensiling to elucidate how the preservation process affects the biomass composition. Such knowledge is important for a biorefinery of seaweeds.