Nitrogen Effect on Water-Soluble Polysaccharide Accumulation in Streblonema sp. (Ectocarpales, Phaeophyceae)

Abstract

The water-soluble polysaccharides of brown algae attract the increasing attention of researchers as an important class of polymeric materials of biotechnological interest. The sole source for production of these polysaccharides has been large brown seaweeds such as members of Laminariales and Fucales. A new source of water-soluble polysaccharides is suggested here: it is a filamentous brown alga Streblonema sp., which can be cultivated under controlled conditions in photobioreactors that allow obtaining algal biomass with reproducible content and quality of polysaccharides. The accumulation of water-soluble polysaccharides can be stimulated by macronutrient limitation. In response to nitrogen deficiency, Streblonema sp. accumulated water-soluble polysaccharides (WSPs) rich in laminaran. WSP accumulation started after 3-4 days following nitrate depletion and reached a plateau at around day 7. Polysaccharide accumulation was related to cellular nitrogen content. The critical internal N level that triggered the onset of polysaccharide accumulation was 2.3% dry weight (DW); at a cellular N concentration less than 1.4% DW, the polysaccharide synthesis stopped. Upon nitrate re-supply, mobilization of WSP occurred after 3 days. These results suggest that a two-stage cultivation process could be used to obtain large algal biomass with high water-soluble polysaccharide production: a first cultivation stage using nitrate-supplemented medium to accumulate algal biomass followed by a second cultivation stage in a nitrate-free medium for 3 to 7 days to enhance polysaccharide content in the alga.

Optimization of cultivation conditions for enhancing biomass, polysaccharide and protein yields of Chlorella sorokiniana by response surface methodology

“…Many studies have reported that various N sources are important for the growth of algae (Guldhe, Ansari, Singh, & Bux, 2017; Nayak, (7) Y Polysaccharide yield = +0.53 + 6.667 × 10 −3 A + 0.032B + 2.500 × 10 −3 C + 0.046D + 1.000 × 10 −2 AB + 0.042AC − 7.500 Suh, Chang, & Lee, 2019; Shahid et al, 2020;Zhuang, Azimi, Yu, Wu, & Hu, 2018). And there have been many reports on the concentration of nitrogen in the accumulation of microalgae polysaccharides (Razaghi, Godhe, & Albers, 2014;Skriptsova, 2017;Yang, Geng, Wang, & Zhang, 2012). Ammonium and urea are used for large-scale cultivation of microalgae due to low cost, and urea and nitrate are more suitable for the growth of Chlorella sp.…”

Effect of Temperature and Light Intensity on the Polar Lipidome of Endophytic Brown Algae Streblonema corymbiferum and Streblonema sp. In Vitro

“…are poorly studied and information on their biochemical composition is almost completely absent. These algae have a high growth rate and can be cultivated under controlled conditions in photobioreactors, which makes them convenient objects for research and promising sources of bioactive substances [ 20 ]. The aim of this study was to determine the effect of temperature and light intensity on the composition of molecular species of polar lipids in S. corymbiferum and Streblonema sp.…”