Abstract
The large brown seaweeds (kelps) are potential sources of protein for animal feed. They have lower protein
contents than most red and green algae, but due to potential for large-scale production, they may represent a
significant future protein source. The impact of pH, temperature and polysaccharide-degrading enzymes on the
solubility and extraction yields of protein from wet Saccharina latissima biomass was investigated. The protein
solubility increased with increasing pH and reached maximum of 23% at pH 11, determined as total amino acids
(TAA). The enzyme treatments increased the release of soluble compounds by 30–35%. The highest protein yield
obtained was 19%, using a ratio of water to wet seaweed of 1:1 for extraction. Even if the yields can be increased
by increasing the water amounts used for extraction, the majority of the protein would remain in the insoluble
residue after separation. The strategy for production of a larger quantity of protein-enriched biomass was
therefore to maintain the insoluble fraction as the product. A pilot scale production was carried out, also
including the red algae Palmaria palmata. In total 750 kg S. latissima and 195 kg P. palmata were processed. The
protein content in the product increased from 10 to 20% of dry weight (dw) for S. latissima and from 12 to 28%
for P. palmata, with yields of 79 and 69%, respectively. The ash content was reduced from 44 to 26% and from 12
to 5% of dw, respectively, for the two species. The main protein loss was free amino acids, which constituted
approximately 10% of TAA in the feedstocks. Less essential than non-essential amino acids were lost, thus, the
essential amino acids were enriched in the product.
contents than most red and green algae, but due to potential for large-scale production, they may represent a
significant future protein source. The impact of pH, temperature and polysaccharide-degrading enzymes on the
solubility and extraction yields of protein from wet Saccharina latissima biomass was investigated. The protein
solubility increased with increasing pH and reached maximum of 23% at pH 11, determined as total amino acids
(TAA). The enzyme treatments increased the release of soluble compounds by 30–35%. The highest protein yield
obtained was 19%, using a ratio of water to wet seaweed of 1:1 for extraction. Even if the yields can be increased
by increasing the water amounts used for extraction, the majority of the protein would remain in the insoluble
residue after separation. The strategy for production of a larger quantity of protein-enriched biomass was
therefore to maintain the insoluble fraction as the product. A pilot scale production was carried out, also
including the red algae Palmaria palmata. In total 750 kg S. latissima and 195 kg P. palmata were processed. The
protein content in the product increased from 10 to 20% of dry weight (dw) for S. latissima and from 12 to 28%
for P. palmata, with yields of 79 and 69%, respectively. The ash content was reduced from 44 to 26% and from 12
to 5% of dw, respectively, for the two species. The main protein loss was free amino acids, which constituted
approximately 10% of TAA in the feedstocks. Less essential than non-essential amino acids were lost, thus, the
essential amino acids were enriched in the product.