Monthly changes in the content of fucans, their constituent sugars and sulphate in cultured Laminaria japonica

Abstract

Crude fucan was extracted monthly from makonbu, Laminaria japonica Areschoug, cultured from April to October at a southern site of the Hokkaido bay. The crude fucan yield tended to gradually increase from April to September, and rose markedly in October when spore formation was over. The fucans were fractionated on DEAE-Sephadex A-25 into three acidic components, A, Band C. In all the monthly extracts, fraction C was the largest. It was entirely free of laminaran and alginate, as was fraction B. Several sugars such as mannose and glucuronic acid, were identified in fraction C beside a large amount of fucose and sulphate. Only the proportion of the latter two constituents continued to increase as the alga matured to reach twice or even more than three times as much as all the other sugars in the September extract.

Influence of Species, Geographic Location, Seasonal Variation and Extraction Method on the Fucoidan Yield of the Brown Seaweeds of Gulf of Mannar, India

“…Seaweeds in shallow region are exposed to sunlight during low tide and so would be expected to have more amount of fucoidan as they develop defence mechanisms against dryness [24] . Since, Hare Island is characterized with shallow coastal shore with the depth of less than 1 feet, where seaweeds are often exposed to sunlight during low tide, the weeds collected from this region gave higher yields when compared to those collected from Valinokkam, which has rocky shores with depth more than 1 m. Another fact that supports this theory is that seaweeds when exposed to sunlight, their sugar content would increase and the UV rays of sunlight might destroy cellular constituents [25] .…”

“…A similar pattern was observed for other species, S. oligocystum and S. longifolium. Few studies have earlier reported that variations in the yield of fucoidan and its derivatives are affected by the season in which seaweeds are collected [25] and plant maturity [27] . The authors also reported a correlation between fucoidan yield and seasonality; and more fucoidan was obtained during the reproductive stages of the seaweed.…”

Industrial-scale bioethanol production from brown algae: Effects of pretreatment processes on plant economics

“…Fucoidan is a sulfated fucan that contains other sugars, such as galactose, xylose, and uronic acid; it mainly consists of sulfated L-fucose, which can be easily extracted from the cell wall of brown algae by hot water [15] or acid solution [16]. The molecular structure of fucoidan differs depending on the algal species [15,17], extraction process [18], season of harvest, and local climatic conditions [16,19]. Although brown algal fucoidans are complex and heterogeneous, recent structural analyses have revealed the presence of ordered repetitive fucoidan units in several species [20].…”

Fucoidans of brown algae: Biosynthesis, localization, and physiological role in thallus

“…As has been established, the content of polysaccharide in tissues of algae and its structure significantly vary during the year [2,54,72,96,102], which is supposedly determined by seasonal variations in such abiotic factors as tem perature, the concentration of mineral nutrients, and illumination [27,96]. However, there is no experimen tal evidence that these environmental factors regulate fucoidan accumulation and its compositional struc ture.…”

“…The contents and compositional structure of sul fated polysaccharides depend on the age of algae to a significant extent. Several researchers have found a higher fucoidan content in the tissues of old algae as compared to young ones [54,111]. Moreover, old algae were shown to synthesize fucoidans with a higher fucose content than young algae do [111].…”