Chapter 4
Alginates
Abstract Alginates are obtained from brown algae, which are mainly found in
marine aquatic environment. Alginate chemical structure is characterized by the
presence of mannuronic or guluronic acid repeating unit in either alternating or block
forms within the polymer chain. They form a part of the cell wall where they provide
strength and flexibility to the cell wall. The chapter reviews a number of extraction
methods used and then discusses the environmental impact of the extraction process.
Alginates find application in a variety of industries which includes food, biomedical,
textiles and others. Alginates can be said to be one of the well-explored aquatic
biopolymers. The chapter discusses the current state and some of the limitations to
its commercial production and presents future perspectives on alginates.
Keywords Alginates · Galactose · Polymer · Brown algae · Aquatic ·
Phycocolloid
4.1 Introduction
Alginates are natural polysaccharides which are present in the cell walls of brown
algae (brown seaweed). They are extracted mainly using chemical methods with
additional processing such as gel pressing and filtration. Alginates are a general term
which refers to salts of alginic acid as well as derivatives of alginic acids and its salts.
Within this chapter, alginates refer to salts of alginic acid: sodium alginate, calcium
alginate and magnesium alginate. Another term, alginocytes, refers to sources of
alginates. Brown marine algae are the main known alginocytes.
Various forms of alginates exist; however, sodium alginates are most common due
to its solubility in cold water which makes it easier to extract and apply. As alginates
gain more commercial value, the cultivation of alginocytes (alginate producing algae)
for alginate production is on the rise. FAO reports an annual increase of over 6% in
the cultivation of brown algae, the main source of alginates. A large proportion of the
seaweeds grown commercially is grown from aquaculture where they are grown in
controlled environment for optimal yield and profitability. The increase in demand
for seaweed can in part be attributed to increased health consciousness and demand
for more non-animal-based food and pharmaceuticals. Alginate competes with the
© Springer International Publishing 2020
O. Olatunji, Aquatic Biopolymers, Springer Series on Polymer and Composite Materials,
https://doi.org/10.1007/978-3-030-34709-3_4
67
Alginates
Abstract Alginates are obtained from brown algae, which are mainly found in
marine aquatic environment. Alginate chemical structure is characterized by the
presence of mannuronic or guluronic acid repeating unit in either alternating or block
forms within the polymer chain. They form a part of the cell wall where they provide
strength and flexibility to the cell wall. The chapter reviews a number of extraction
methods used and then discusses the environmental impact of the extraction process.
Alginates find application in a variety of industries which includes food, biomedical,
textiles and others. Alginates can be said to be one of the well-explored aquatic
biopolymers. The chapter discusses the current state and some of the limitations to
its commercial production and presents future perspectives on alginates.
Keywords Alginates · Galactose · Polymer · Brown algae · Aquatic ·
Phycocolloid
4.1 Introduction
Alginates are natural polysaccharides which are present in the cell walls of brown
algae (brown seaweed). They are extracted mainly using chemical methods with
additional processing such as gel pressing and filtration. Alginates are a general term
which refers to salts of alginic acid as well as derivatives of alginic acids and its salts.
Within this chapter, alginates refer to salts of alginic acid: sodium alginate, calcium
alginate and magnesium alginate. Another term, alginocytes, refers to sources of
alginates. Brown marine algae are the main known alginocytes.
Various forms of alginates exist; however, sodium alginates are most common due
to its solubility in cold water which makes it easier to extract and apply. As alginates
gain more commercial value, the cultivation of alginocytes (alginate producing algae)
for alginate production is on the rise. FAO reports an annual increase of over 6% in
the cultivation of brown algae, the main source of alginates. A large proportion of the
seaweeds grown commercially is grown from aquaculture where they are grown in
controlled environment for optimal yield and profitability. The increase in demand
for seaweed can in part be attributed to increased health consciousness and demand
for more non-animal-based food and pharmaceuticals. Alginate competes with the
© Springer International Publishing 2020
O. Olatunji, Aquatic Biopolymers, Springer Series on Polymer and Composite Materials,
https://doi.org/10.1007/978-3-030-34709-3_4
67