Macroalgal Value Chain: Value-Added Products

Introduction

The economic potential for an algal industry is fundamentally linked to the sheer diversity of value-added products that can be obtained from algae. While the bulk of algal production currently goes into food (sea vegetables) and hydrocolloids (FAO, 2014) it is worth noting that the macro-algal value chain is diverse and thereby presents numerous opportunities for niche products many of which have the potential to be of very high value.

The range of products that are obtained from macroalgae and used in our daily lives suggests that, at least in the developed world, no-one can go through a single day without directly consuming something that contains at least some macroalgal derived constituents or using something that has required the use of macroalgal products in its manufacture. With applications as diverse as food for human consumption (e.g. the wrap on sashimi rolls), as a food additive (e.g. to improve mouthfeel in yogurt or keeping the head on a glass of beer), in pharmaceuticals (typically as a stabilizer), cosmetics (facial scrubs and soaps) through to screen printing (materials for shirts, skirts and bed-sheets) and even in the production of welding rods that have been used in assembling the steel frames of household furniture (to ensure an even burn and smooth join).

Macroalgae’s ability to deliver a wide range of input material to other processes can be illustrated by the historic operations of Hercules Powder Co that established a macroalgae best operation in California in 1914. This operation employed 1400 in three 8-hour shifts and processed an average of 1,000 ton kelp per day. The kelp was harvested using three purpose-built three giant harvesters (the Joplin, Kenvil, and Bacchus) and supported by nine transport barges, four towboats, and a floating machine shop – this was the largest macroalgae harvest fleet in the world at the time. The plant produced 228,000 gallons of acetone per month. The plant also produced esters, primarily ethyl acetate, for use in artificial leather and lacquer preparation; ethyl anhydride for use in the production of cellulose acetate for non-inflammable airplane dope; it further produced belt cement for gluing together strands of leather belting, and film cement for joining together moving picture films; left over from acetone production were used to make an acid-proof paint. The plant also produced large quantities of potash from the kelp. The plant extracted, during its 6-year operation, 54 chemical products from the kelp but overlooked the economic potential of alginates. This plant, the largest of the kelp plants, formed part of California's World War I kelp industry which in turn formed one of the largest industries ever created for the processing of oceanic raw materials. (Williams, 1920; Neushul, 1989).

Figure 1.

The Hercules Powder Company’s San Diego Kelp Plant. This plant was designed, primarily, to procure acetone for the manufacture of British cordite, prior to the entry of the United States into the war. This panoramic view of the great Kelp Reducing Plant of the Hercules Powder Co., at Potash {near San Diego, California), shows in the left back ground the 156 kelp digestion tanks, each with a capacity of 50,000 gallons. In the center of the picture at right is the converter building of the acetone group, with the carpenter shop and laboratory on the left. Back of these are the steam dryer, heat transfer, centrifugal crystallizer and evaporation buildings. On the right of the picture in the foreground is the generator division of the acetone group, back of which are the power and warehouses and in the background the direct heal dryer. (Williams, 1920, p.32-33: https://ia800701.us.archive.org/19/items/historyofmanufac00will/historyofmanufac00will.pdf)

Figure 2.

The Bacchus kelp harvester (https://projectwatershed.ca/the-cape-lazo-kelp-caper-earth-day-edition-comox-record/)