68
4 Alginates
human and animal edible algae as a lot of the algae being cultivated globally are also
used for human consumption and animal feed. By 2024, alginate market is predicted
to increase in value up to about 87 billion USD.
Biopolymers with diverse applications offer the producer and supplier an equally
diverse distribution channel, whereby the product is in demand in several industries. Alginate is one of such polymers, and its applications include in food, textiles,
pharmaceutics and more. Some of these applications are already being made into
commercial products while others are still at an early research stage. Alginates are
applied in textiles, cosmetics, paper, food and pharmaceutics.
Alginates are one of three phycocolloids which can be obtained from algae. The
two others are agar and carrageenan. Alginates are made from brown algae while agar
and carrageenan are obtained from red algae. Alginates are one of the commercially
well-explored biopolymers of aquatic source. Since they are produced primarily from
algae, they are one of the polymers which are exclusively sourced from the aquatic
environment. The continued availability of alginates is therefore significantly affected
by the dynamics of the aquatic environment. The production of these phycocolloids
competes with the production of other products such as biofuel, fertilizers and sewage
treatment materials from algae. It is therefore important to understand the production
and impacts of alginate production from these algae in order to assess the adequate
utilization of this particular aquatic resource.
4.2 Occurrence in Nature
Brown seaweeds are the only known source of alginates. Although alginates from
seaweed were not discovered until the later part of the 1800s, for centuries, coastal
communities have grown around gathering of seaweed. Seaweeds are aquatic plants
which grow naturally in different aquatic conditions, from slow-moving to more
turbulent waters. There are three classifications of seaweeds: brown, red and green.
Brown seaweeds are largest in size, up to 20 m long; however, smaller ones exist ranging in 2–4 m long or even smaller 30–60 cm length (McHugh 2003). Red seaweeds
are smallest with length ranging under a meter while green seaweeds are the smallest.
Here, we focus our interest on the brown seaweed species. These grow best in cold
waters around 20 °C in countries such as South Africa, Argentina, Canada, Australia,
Chile, Norway, Ireland, Mexico, Scotland, Northern Ireland, USA and other countries
in the Southern and Northern Hemisphere. Factors which affect growth of seaweeds
include temperature, nutrient content, salinity, light penetration and turbulence of
water.
Despite aquaculture dominating the global seaweed production, most of the
alginophytes are from species which grow wild such as laminarin and Ascophyllum. Most of the brown seaweeds used for alginate production have a complex
reproductive cycle which makes their cultivation less cost-effective than when harvested from wild stock (McHugh 2003). However, as further understanding of the
diverse reproductive cycle of these algae is developed, more effective methods for
4 Alginates
human and animal edible algae as a lot of the algae being cultivated globally are also
used for human consumption and animal feed. By 2024, alginate market is predicted
to increase in value up to about 87 billion USD.
Biopolymers with diverse applications offer the producer and supplier an equally
diverse distribution channel, whereby the product is in demand in several industries. Alginate is one of such polymers, and its applications include in food, textiles,
pharmaceutics and more. Some of these applications are already being made into
commercial products while others are still at an early research stage. Alginates are
applied in textiles, cosmetics, paper, food and pharmaceutics.
Alginates are one of three phycocolloids which can be obtained from algae. The
two others are agar and carrageenan. Alginates are made from brown algae while agar
and carrageenan are obtained from red algae. Alginates are one of the commercially
well-explored biopolymers of aquatic source. Since they are produced primarily from
algae, they are one of the polymers which are exclusively sourced from the aquatic
environment. The continued availability of alginates is therefore significantly affected
by the dynamics of the aquatic environment. The production of these phycocolloids
competes with the production of other products such as biofuel, fertilizers and sewage
treatment materials from algae. It is therefore important to understand the production
and impacts of alginate production from these algae in order to assess the adequate
utilization of this particular aquatic resource.
4.2 Occurrence in Nature
Brown seaweeds are the only known source of alginates. Although alginates from
seaweed were not discovered until the later part of the 1800s, for centuries, coastal
communities have grown around gathering of seaweed. Seaweeds are aquatic plants
which grow naturally in different aquatic conditions, from slow-moving to more
turbulent waters. There are three classifications of seaweeds: brown, red and green.
Brown seaweeds are largest in size, up to 20 m long; however, smaller ones exist ranging in 2–4 m long or even smaller 30–60 cm length (McHugh 2003). Red seaweeds
are smallest with length ranging under a meter while green seaweeds are the smallest.
Here, we focus our interest on the brown seaweed species. These grow best in cold
waters around 20 °C in countries such as South Africa, Argentina, Canada, Australia,
Chile, Norway, Ireland, Mexico, Scotland, Northern Ireland, USA and other countries
in the Southern and Northern Hemisphere. Factors which affect growth of seaweeds
include temperature, nutrient content, salinity, light penetration and turbulence of
water.
Despite aquaculture dominating the global seaweed production, most of the
alginophytes are from species which grow wild such as laminarin and Ascophyllum. Most of the brown seaweeds used for alginate production have a complex
reproductive cycle which makes their cultivation less cost-effective than when harvested from wild stock (McHugh 2003). However, as further understanding of the
diverse reproductive cycle of these algae is developed, more effective methods for