8.3 Chemistry of Ulvans
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polymer can be altered by breaking specific glycosidic bonds using either chemical
(Pengzhan et al. 2004) or enzyme hydrolysis (Reisky et al. 2018) of the ulvan polymer
chain. The solution properties at different pH can be used to develop ulvan-based
products with specific rheological properties. Ulvans therefore offer a broad range
of tuneable chemical and rheological properties which presents a range of potential
applicabilities.
8.3.1 Biodegradation of Ulvans
Understanding the biodegradation of ulvans is important in assessing their safe degradation when released into the environment and when consumed as food, cosmetics
or therapeutics. It is also important in understanding the structure of ulvans. The
biodegradation products and the enzymes which catalyze the biodegradation provide
an insight into the structural configuration of the ulvan as well as an understanding
of the biological activity of the microbes which degrade ulvans.
Ulvanolytic enzymes refer to enzymes which are capable of degrading ulvans.
Microbes identified to be capable of degrading of ulvan polysaccharide such as gramnegative marine bacterium, ochrobactrum and flavobacterium produce ulvanolytic
enzymes (Michel and Czjzek 2014). These enzymes are capable of cleaving specific
glycosidic bonds, for example, a type of ulvanolytic enzyme called ulvan lyases
catalyzes the cleavage of the bonds between sulfated rhamnose and glucuronic acid
or that between rhamnose and iduronic acid (Nyvall Collen et al. 2011). Effectiveness
of ulvanolytic enzymes therefore depends on the chain configuration of the specific
ulvan and the repeating disaccharide units within the ulvan polymeric chain. Ulvan
is not degraded by any enzyme produced by the human body, and it is also able to
survive the gastrointestinal tract and colon undigested (Misurcova et al. 2012). This
makes it a good option for dietary-soluble fiber.
8.4 Availability of Raw Material
Green algae are a renewable natural resource for biopolymer production. It also has
the additional advantage of growing in more diverse habitat with varying abiotic
factors. Compared to red or brown algae which primarily grow in marine waters,
green algae grow in both marine and freshwater. The ulvan producing species grow
in marine and freshwater. Example of marine species is U. rigida (Tabarsa et al.
2018) and that of freshwater is Ulva thalli (Rybak et al. 2012). This occurrence in
diverse habitat means less limitation on region where the raw material for production
of ulvans can be the sources. A readily available resource from multiple regions is
always better for the economy than resources concentrated in only a few regions. This
concentration of resources in limited regions has led to some of the socioeconomic
problems of other natural resources such as crude oil and minerals.
173
polymer can be altered by breaking specific glycosidic bonds using either chemical
(Pengzhan et al. 2004) or enzyme hydrolysis (Reisky et al. 2018) of the ulvan polymer
chain. The solution properties at different pH can be used to develop ulvan-based
products with specific rheological properties. Ulvans therefore offer a broad range
of tuneable chemical and rheological properties which presents a range of potential
applicabilities.
8.3.1 Biodegradation of Ulvans
Understanding the biodegradation of ulvans is important in assessing their safe degradation when released into the environment and when consumed as food, cosmetics
or therapeutics. It is also important in understanding the structure of ulvans. The
biodegradation products and the enzymes which catalyze the biodegradation provide
an insight into the structural configuration of the ulvan as well as an understanding
of the biological activity of the microbes which degrade ulvans.
Ulvanolytic enzymes refer to enzymes which are capable of degrading ulvans.
Microbes identified to be capable of degrading of ulvan polysaccharide such as gramnegative marine bacterium, ochrobactrum and flavobacterium produce ulvanolytic
enzymes (Michel and Czjzek 2014). These enzymes are capable of cleaving specific
glycosidic bonds, for example, a type of ulvanolytic enzyme called ulvan lyases
catalyzes the cleavage of the bonds between sulfated rhamnose and glucuronic acid
or that between rhamnose and iduronic acid (Nyvall Collen et al. 2011). Effectiveness
of ulvanolytic enzymes therefore depends on the chain configuration of the specific
ulvan and the repeating disaccharide units within the ulvan polymeric chain. Ulvan
is not degraded by any enzyme produced by the human body, and it is also able to
survive the gastrointestinal tract and colon undigested (Misurcova et al. 2012). This
makes it a good option for dietary-soluble fiber.
8.4 Availability of Raw Material
Green algae are a renewable natural resource for biopolymer production. It also has
the additional advantage of growing in more diverse habitat with varying abiotic
factors. Compared to red or brown algae which primarily grow in marine waters,
green algae grow in both marine and freshwater. The ulvan producing species grow
in marine and freshwater. Example of marine species is U. rigida (Tabarsa et al.
2018) and that of freshwater is Ulva thalli (Rybak et al. 2012). This occurrence in
diverse habitat means less limitation on region where the raw material for production
of ulvans can be the sources. A readily available resource from multiple regions is
always better for the economy than resources concentrated in only a few regions. This
concentration of resources in limited regions has led to some of the socioeconomic
problems of other natural resources such as crude oil and minerals.