Effect of nitrogen source on the growth, lipid, and valuable carotenoid production in the green microalga Chromochloris zofingiensis

In this study, silver nanoparticles (AgNPs) were green-synthesized extracellularly by the action of bioactive compounds in cultural filtrates of green microalga Scenedesmus obliquus (KY621475). The influences of six different nitrogen sources (i.e., NaNO3, CO(NH4)2, (NH4)2CO3, KNO3, NH4NO3, and (NH4)2SO4) on extracellular biosynthesis of AgNPs were observed by UV–Visible spectroscopy (380–425 nm) and confirmed using high-resolution transmission electron microscopy (HRTEM). The highest biomass production was observed in the case of urea and ammonium carbonate treatments, which, surprisingly, showed negative activity for AgNPs biosynthesis. Considering their coupling and compatible presence in cultural filtrates, reductases (especially nitrate reductase) as reduction agents are assumed to play a key role in the extracellular biosynthesis of AgNPs. The cultural filtrates of the potassium and sodium nitrate treatments produce AgNPs of relatively small size (5–10 and 4–10 nm, respectively), smaller than those produced by filtrate of ammonium nitrate treatment. The antimicrobial activity of produced AgNPs was a function mainly of particle size, which was influenced by the nitrogen source of the microalgal culture. The AgNPs produced from the KNO3 and NaNO3 cultural filtrates performed the best as antimicrobial agents.

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Toxicity of single-walled carbon nanotubes on green microalga Chromochloris zofingiensis

Chinese Journal of Oceanology and Limnology ◽

10.1007/s00343-013-2131-1 ◽

2013 ◽

Vol 31 (2) ◽

pp. 306-311 ◽

Cited By ~ 6

Author(s):

Yan Wang ◽

Kaijing Yang

Keyword(s):

Carbon Nanotubes ◽

Single Walled Carbon Nanotubes ◽

Single Walled Carbon ◽

Green Microalga ◽

Walled Carbon Nanotubes ◽

Chromochloris Zofingiensis

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Lipid and Carotenoid Production by Rhodotorula glutinis with a Combined Cultivation Mode of Nitrogen, Sulfur, and Aluminium Stress

Applied Sciences ◽

10.3390/app9122444 ◽

2019 ◽

Vol 9 (12) ◽

pp. 2444 ◽

Cited By ~ 11

Author(s):

Nora Elfeky ◽

Mostafa Elmahmoudy ◽

Yue Zhang ◽

JianLi Guo ◽

Yongming Bao

Keyword(s):

Nitrogen Source ◽

High Performance ◽

Lipid Synthesis ◽

Rhodotorula Glutinis ◽

Nitrogen Sources ◽

Synthesis Rate ◽

Carotenoid Production ◽

Total Pigment ◽

Relative Productivity

Torulene is a promising pink pigment, produced only by yeasts and fungi, and its production is still in a developing stage due to the low production rate. Accordingly, this study focuses on maximizing torulene production by Rhodotorula glutinis using shaken flask fermentation. The effect of different nitrogen sources, and C/N and C/S ratios on lipid and carotenoid production by R. glutinis was studied using 60 g/L glucose. The largest cells filled with golden fluorescence lipid bodies were observed using fluorescence microscopy when peptone was used as a nitrogen source. The highest total pigment (0.947 mg/L) and carotenoid relative productivity (Car-RP) (89.04 µg/g) were obtained at C/N 146 and C/S 120, and with ammonium sulfate as a nitrogen source, with 62% torulene domination using High Performance Liquid Chromatography (HPLC) for identification. Under a high C/N ratio, regardless of the C/S ratio, the carotenoid synthesis rate decreased after three days while the lipid synthesis rate kept increasing to the sixth day. Interestingly, after adding 0.7 mM Al2(SO4)3 to the optimized medium, the total pigment and Car-RP (2.2 mg/L and 212.9 µg/g) sharply increased, producing around 2.16 mg/L torulene (98%) with around 50% decrease in lipid yield. This is the first report on the role of Al2(SO4)3 for enhancing torulene production under lipogenesis condition, which could be used as a potential tool for torulene production.

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