Biorefinery of the green seaweed Ulva lactuca to produce animal feed, chemicals and biofuels

Abstract

The growing world population demands an increase in animal protein production. Seaweed may be a valuable source of protein for animal feed. However, a biorefinery approach aimed at cascading valorisation of both protein and non-protein seaweed constituents is required to realise an economically feasible value chain. In this study, such a biorefinery approach is presented for the green seaweed Ulva lactuca containing 225 g protein (N × 4.6) kg−1 dry matter (DM). The sugars in the biomass were solubilised by hot water treatment followed by enzymatic hydrolysis and centrifugation resulting in a sugar-rich hydrolysate (38.8 g L−1 sugars) containing glucose, rhamnose and xylose, and a protein-enriched (343 g kg−1 in DM) extracted fraction. This extracted fraction was characterised for use in animal feed, as compared to U. lactuca biomass. Based on the content of essential amino acids and the in vitro N (85 %) and organic matter (90 %) digestibility, the extracted fraction seems a promising protein source in diets for monogastric animals with improved characteristics as compared to the intact U. lactuca. The gas production test indicated a moderate rumen fermentation of U. lactuca and the extracted fraction, about similar to that of alfalfa. Reduction of the high content of minerals and trace elements may be required to allow a high inclusion level of U. lactuca products in animal diets. The hydrolysate was used successfully for the production of acetone, butanol, ethanol and 1,2-propanediol by clostridial fermentation, and the rhamnose fermentation pattern was studied.Electronic supplementary materialThe online version of this article (doi:10.1007/s10811-016-0842-3) contains supplementary material, which is available to authorized users.

Can Seaweed Farming Play a Role in Climate Change Mitigation and Adaptation?

“…A stepwise approach to maximizing the benefits from seaweed aquaculture would include to sequentially extract high-value molecules used in the food, pharma or biotech industries, such as bioactive sulphated polysaccharides, pigments, and antioxidants (D'Orazio et al, 2012;Mak et al, 2014;Herrero and Ibáñez, 2015), and then convert-after extraction of carbohydrates for the hydrocollid industry or for biofuels production-the lowervalue residue to protein concentrates with value in the feed industry (Francavilla et al, 2015;Bikker et al, 2016;Seghetta et al, 2016). Algal biorefineries have evolved from concept and laboratory tests to pilot-scale plants involving a range of seaweed species and environments (e.g., Baghel et al, 2014;Lorbeer et al, 2015;Bikker et al, 2016;Masarin et al, 2016), and may soon become commercial operations.…”

“…Algal biorefineries have evolved from concept and laboratory tests to pilot-scale plants involving a range of seaweed species and environments (e.g., Baghel et al, 2014;Lorbeer et al, 2015;Bikker et al, 2016;Masarin et al, 2016), and may soon become commercial operations. The range of potential products also include using the nutrient-rich residues from a biofuel production for fertilizer, which may also serve for C retention in soil (Seghetta et al, 2016).…”

Mitochondrial and chloroplast genome sequences of Ulva ohnoi, a green-tide-forming macroalga in the Southern coastal regions of Japan

“…Species of Ulva are important for some applications, such as food stuffs (Hiraoka and Oka 2008;Holdt and Kraan 2011) and resource of biofuels (Bikker et al 2016). In ecological aspects, some free-floating species of Ulva cause large-scale macroalgal bloom called 'green tide' (Fletcher 1996).…”

Pharmacological Potential of Ulva Species: A Valuable Resource

“…The antioxidant properties of Ulva spp. have been studied form species collected from different part of the world [10,35,36]. As for example, the antioxidant activity, contents of total phenolics and flavonoids were quantified in the methanolic extracts of four Ulva species [37].…”

“…From an economic perspective, the use of Ulva species for different applications has been largely described: bioremediation [7], bioenergy [8], food and feed [9]. A biorefinery approach for industrial exploitation of Ulva constituents have been proposed [10]. To realize an economically feasible value chain, cascading valorization of both protein and non-protein seaweed constituents is required.…”