| 2. |
- Razaghi, Ali, et al.
(författare)
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Effects of nitrogen on growth and carbohydrate formation in Porphyridium cruentum
- 2014
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Ingår i: Central European Journal of Biology. - : Walter de Gruyter GmbH. - 1895-104X .- 1644-3632. ; 9:2, s. 156-162
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Tidskriftsartikel (refereegranskat)abstract
- The microalga Porphyridium cruentum (Rhodophyta) has several industrial and pharmaceutical uses, especially for its polysaccharide production. This study aimed to investigate the influence of nitrogen levels as reflected by altered N:P ratios on the production and content of biomass and carbohydrate. N:P molar ratios were altered in batch cultures to range from 1.6 to 50 using the Redfield ratio of 1:16 as reference. Algal growth (estimated as final cell number, biomass concentration and maximum specific growth rate) was negatively affected at low N:P ratios. The optimal N:P ratio for growth was identified at 35-50, with specific growth rates of 0.19 day(-1) and maximum cell concentrations of 59 center dot 10(8) cells L-1 and 1.2 g dry weight of biomass L-1. In addition, variation in cell size was seen. Cells with larger diameters were at higher N:P ratios and smaller cells at lower ratios. The cellular carbohydrate content increased under reduced nitrogen availability. However, because accumulation was moderate at the lowest N:P ratio, 0.4 g per g dry weight biomass compared to 0.24 at the Redfield ratio of 16:1, conditions for increased total carbohydrate formation were identified at the N:P ratios optimal for growth. Additionally, carbohydrates were largely accumulated in late exponential to stationary phase.
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| 3. |
- Razaghi, Ali, et al.
(författare)
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Screening microalgae for carbohydrate production
- 2011
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Ingår i: Algae Cooperation Event, The Submariner Project, Sweden.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Twelve species belonging to nine classes of microalgae and cyanobacteria were grown under their optimal condition in batch culture. Increase of cell numbers was checked by in vivo fluorescence method during the growth and approximately after two weeks the species were screened for total carbohydrate by Phenol-Sulfuric acid method. The species and their classes which have been studied were in this order; Chlorophyceae (Quadricoccus euryhalinicus, Chlamydomonas euryale, Chlorella sp.), Nephroselmidophyceae (Nephroselmis minuta), Prasinophyceae (Micromonas pussilla, Mantoniella sp.), Cryptophyceae (Proteomonas sulcata), Zygnematophyceae (Spirogyra sp.), Haptophyta/Prymnesiophyceae (Phaeocyctis cf. pouchetii), Rhodophyta/Porphyridiophyaceae, (Porphyridium cruentum), Bacillariophyta/Coscinodiscophyceae (Thalassiosira pseudonana), and Cyanophyceae (Nostoc commune). Finally, the best species with higher carbohydrate production in comparison to others were detected,respectively; Spirogyra sp., Nostoc commune, Porphyridium cruentum, Quadricoccus euryhalinicus and Chlorella sp. with 0,1, 0,09, 0,07, 0,04 and 0,04 (g/L) carbohydrate production, respectively.
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