100
5 Fucoidan
A number of fungi (Rodriguez-Jasso et al. 2010), bacteria (Chang 2010) and
certain invertebrates (Bilan et al. 2005) are known to contain enzymes capable of
degrading fucoidan. The level of activity and mode of activity vary for different
enzymes. For instance, the marine bacteria species such as Formosa algae produce
the enzyme fucoidanase which has the ability to hydrolyze fucoidan (Sichenko et al.
2013). This enzyme can optimally function in a wide range of pH value (6.5–9.1).
The level of activity of fucoidanase has been shown to vary for different fucoidan
structures. For example, fucoidan-utilizing bacteria of the Flavobacteriaceae family
extracted from seawater showed a fucoidan utilization rate of 81.5% for fucoidan
extracted from sea cucumber (Chang 2010), while the enzymes from terrestrial fungi,
Aspergillus niger, can degrade fucoidan from the brown algae Laminaria japonica,
that from Fucus evanescens is hydrolyzed by another type of enzyme from marine
bacteria. Deacetylated fucoidan has been found to be hydrolyzed more readily compared to desulfated fucoidan. This is attributed to the specificity of the enzymes to
the 1 → 4 bonds of the polysaccharide chains, specifically for sulfated alpha-Lfucopyranose. Such degradation by fucoidanase is significant toward producing the
immunomodulatory-active sulfated fuco-oligosaccharide.
With the aim to achieve improved pharmacological bioactivity by producing lower
molecular weight fucoidan from higher molecular weight ones, Lahrsen et al. (2018)
degraded fucoidan from a molecular weight of 4.9–38.2 kDa using hydrogen peroxide. However, the lower molecular weight fucoidans produced, lost their antioxidant and antiproliferative activities. It is, therefore, important that the activities of
fucoidan extracts can be tailored to meet desired bioactivities by optimizing the right
combination and conditions of enzyme activities.
Certain microbes, mainly marine bacteria or mollusks, contain endo- and exoenzymes which can break down fucoidans (Kusaykin et al. 2001). These are important for either understanding the breakdown of the fucoidan-based products when
exposed to the environment at the end of use or in the body or as source of enzymes
used to modify fucoidan into other forms using enzymes. An example of such enzyme
is fucoidan hydrolase, alpha-l-fucosidase. This can be used in combination with a
desulfating enzyme arylsulfatase to break down the sulfated carbohydrate fucoidan
structure (Silchenko et al. 2013). This results in the formation of sulfated oligosaccharides as a result of cleavage of the fucoidan chain into shorter chains. Fucose
is also produced in the process. Interestingly, some enzymes which are capable of
cleaving or hydrolyzing fucoidans from some species are not able to do the same
for fucoidans from other species. This is due to the diverse structure of fucoidans
as they vary for different sources. For example, the enzyme extracted from marine
bacteria which degrade fucoidan from Fucus evanescens and Fucus vesiculosus does
not hydrolyze fucoidan from another species Saccharina cichorioides (RodriguezJasso et al. 2010). This difference in the degradation process limits the large-scale
modification of fucoidans to obtain more standard batches, for example, to control
the chain length or degree of sulfation.
5 Fucoidan
A number of fungi (Rodriguez-Jasso et al. 2010), bacteria (Chang 2010) and
certain invertebrates (Bilan et al. 2005) are known to contain enzymes capable of
degrading fucoidan. The level of activity and mode of activity vary for different
enzymes. For instance, the marine bacteria species such as Formosa algae produce
the enzyme fucoidanase which has the ability to hydrolyze fucoidan (Sichenko et al.
2013). This enzyme can optimally function in a wide range of pH value (6.5–9.1).
The level of activity of fucoidanase has been shown to vary for different fucoidan
structures. For example, fucoidan-utilizing bacteria of the Flavobacteriaceae family
extracted from seawater showed a fucoidan utilization rate of 81.5% for fucoidan
extracted from sea cucumber (Chang 2010), while the enzymes from terrestrial fungi,
Aspergillus niger, can degrade fucoidan from the brown algae Laminaria japonica,
that from Fucus evanescens is hydrolyzed by another type of enzyme from marine
bacteria. Deacetylated fucoidan has been found to be hydrolyzed more readily compared to desulfated fucoidan. This is attributed to the specificity of the enzymes to
the 1 → 4 bonds of the polysaccharide chains, specifically for sulfated alpha-Lfucopyranose. Such degradation by fucoidanase is significant toward producing the
immunomodulatory-active sulfated fuco-oligosaccharide.
With the aim to achieve improved pharmacological bioactivity by producing lower
molecular weight fucoidan from higher molecular weight ones, Lahrsen et al. (2018)
degraded fucoidan from a molecular weight of 4.9–38.2 kDa using hydrogen peroxide. However, the lower molecular weight fucoidans produced, lost their antioxidant and antiproliferative activities. It is, therefore, important that the activities of
fucoidan extracts can be tailored to meet desired bioactivities by optimizing the right
combination and conditions of enzyme activities.
Certain microbes, mainly marine bacteria or mollusks, contain endo- and exoenzymes which can break down fucoidans (Kusaykin et al. 2001). These are important for either understanding the breakdown of the fucoidan-based products when
exposed to the environment at the end of use or in the body or as source of enzymes
used to modify fucoidan into other forms using enzymes. An example of such enzyme
is fucoidan hydrolase, alpha-l-fucosidase. This can be used in combination with a
desulfating enzyme arylsulfatase to break down the sulfated carbohydrate fucoidan
structure (Silchenko et al. 2013). This results in the formation of sulfated oligosaccharides as a result of cleavage of the fucoidan chain into shorter chains. Fucose
is also produced in the process. Interestingly, some enzymes which are capable of
cleaving or hydrolyzing fucoidans from some species are not able to do the same
for fucoidans from other species. This is due to the diverse structure of fucoidans
as they vary for different sources. For example, the enzyme extracted from marine
bacteria which degrade fucoidan from Fucus evanescens and Fucus vesiculosus does
not hydrolyze fucoidan from another species Saccharina cichorioides (RodriguezJasso et al. 2010). This difference in the degradation process limits the large-scale
modification of fucoidans to obtain more standard batches, for example, to control
the chain length or degree of sulfation.