Biorefinery for the co-production of protein, hydrochar and additional co-products from a green seaweed Ulva sp. with subcritical water hydrolysis

Valorization of waste materials from seaweed industry: An industry survey based biorefinery approach

“…While developing proper storage, distribution and additional processing technologies for liquid or solid waste materials needs to coincide with an extensive exploration of the commercial potential of different waste materials, Bixler and Porse recognized the stagnant growth of seaweed hydrocolloid markets and tightening seaweed supplies in recent years (i.e., a decrease in annual growth rate from 3% to 5% in 1990s to 1% to 3%) 25 . Therefore, aligned with the increasing recent interest in circular economies, diversifying product portfolio through the valorization of major waste streams in seaweed industry could turn out to be one of the major strategies to vitalize this industry by broadening market opportunities and possibly reducing environmental costs associated with waste being generated 14,25 …”

“…Furthermore, Kim et al reported the co‐production of alginate and biodiesel from a brown seaweed, Laminaria japonica , via the heterotrophic cultivation of an oleaginous yeast in the supernatant liquid from the autoclaved seaweed solution prior to the alginate extraction in the solid phase 13 . Similarly, Polikovsky et al demonstrated that hydrochar production can be combined with the co‐production of ethanol, proteins and additional hydrolyzed monomers from ‘waste’ seaweed biomass 14 . In addition, Cho et al reported a substantial loss of edible seaweed Pyropia due to the discoloration caused by nutrient depletion or pathogens, and proposed the utilization of low‐quality discoloured laver in the production of value‐added compound 10 .…”

“…In this opinion article, some of these waste materials generated from seaweed industry are discussed with the focus of initiating explorations of their potential as a raw material for the production of novel value‐added products. Although recent studies have demonstrated intensified seaweed biorefinery approaches through which different constituents of seaweeds could be sequentially extracted or utilized via chemical, biological conversion processes, 15 this cascading design of seaweed biorefinery demonstrated in the literature may not be readily adaptable in the developing seaweed industry due to capital costs associated with the assembly and operation of new conversion and separation technologies at scale 2,14,15 . A more immediate and operable pathway towards discovering new valorization opportunity may lie in discovering utility of established waste‐streams.…”

Macroalgal biorefinery concepts for the circular bioeconomy: A review on biotechnological developments and future perspectives

“…One way to enhance the LCA and TEA of a bioprocess is the adoption of 'green extraction technologies', which are particularly attractive to incorporate within cascading biorefineries due to their environmentally friendly and less hazardous status plus their ability to reduce energy consumption and promote the recovery of bioproducts of greater purity and quality [124]. Subcritical water hydrolysis treatment (180 • C, 10.5 bar for 40 min at a solids loading rate of 8 % (w/w)) using seawater, was applied to a mixed composition of Ulva rigida and Ulva fascia in an integrated biorefinery study by Polikovsky et al [125]. The treatment yielded multiple bioproducts that included a biochar residue and a liquid hydrolysate fraction containing a plethora of biocompounds such as 5.2 mg HMF, 24.1 mg total monosaccharides, free amino acids, protein corresponding to 84.9 % of the total protein, and 4.6 mg of bioethanol (g − 1 of dried Ulva spp).…”

Production of solid hydrochar from waste seaweed by hydrothermal carbonization: effect of process variables

“…Seaweed as a novel feedstock for hydrothermal carbonization has been recently studied. For example, the group of Goldberg studied the hydrochar production using Ulva sp [32,33] and Cao et al used red seaweed to produce hydrochar via a microwave assisted carbonisation [34].…”