Characterization of cell structural change, growth, lipid accumulation, and pigment profile of a novel oleaginous microalga, Vischeria stellata (Eustigmatophyceae), cultured with different initial nitrate supplies

Abstract

The appropriate microalgal species and the optimal nitrogen supply in culture medium are vital factors in maximizing biomass and metabolite productivities in microalgae. Vischeria stellata is an edaphic unicellular eustigmatophycean microalga. Cytological and ultrastructural characteristics and the effects of different initial nitrate-nitrogen concentrations on growth, lipid accumulation, fatty acid profile, and pigment composition were investigated in the present study. The cell structures of V. stellata changed with the degree of nutrient utilization and growth phase. The initial nitrate concentration for the optimal growth of V. stellata ranged from 6.0 to 9.0 mM. The maximum total lipid (TLs), neutral lipid (NLs), and total fatty acid (TFAs) contents were 55.9, 51.9, and 44.7 % of dry biomass, respectively. The highest volumetric productivity of TLs, NLs, and TFAs reached 0.28, 0.25, and 0.21 g L −1 day −1 , respectively. V. stellata had a suitable fatty acid profile for biodiesel production, as well as containing eicosapentaenoic acid (EPA) for nutraceutical applications. In addition, the content β-carotene, increased gradually as culture time was prolonged, resulting in its exclusive production at the end of cultivation. V. stellata is a promising microalgal strain for the production of biofuels and bioproducts.

Evaluation and transcriptome analysis of the novel oleaginous microalga Lobosphaera bisecta (Trebouxiophyceae, Chlorophyta) for arachidonic acid production

“…The supernatant was collected into the same glass vial and the extraction process was repeated. The determination of lipid content was by gravimetric method and the detail was described in Gao et al [11].…”

“…Materials And Methods4.1 Algal strain and culture conditionsLobosphaera bisecta SAG2043 was obtained from Culture Collection of Algae at Göttingen University, Germany, and deposited in our laboratory at Jinan university. Cultures were maintained in modified BG-11 medium[11]. Initial synchronized cultures were grown in 250 mL Erlenmeyer flask with 150 mL working volume.…”

Lipid Accumulation of Chlorella Vulgaris Under Different Phosphate Concentrations

“…3. Changes in the content PO 4 3-and N-NO 3 -in the culture medium in the first and second part of the research tłuszczowe występujące w gatunku Chlorella vulgaris to: kwas tridekanowy (C13:0), kwas palmitynowy (C16:0), kwas stearynowy (C18:0), kwas kwas elaidynowy (C18:1 TRANS 9), kwas gamma-linolenowy (C18:3 CIS 6), kwas eikozatrienowy (C20:3 CIS 11). W oleju pochodzącym z hodowli SZOK_P uzyskano także kwas arachidynowy (C20:4 CIS 5).…”

“…W części pierwszej zmierzano do określenia efektywności oraz tempa wykorzystania biogennych substancji pożywkowych, tzn. ortofosforanów (PO 4 3-) i azotanów (N-NO 3 -) medium hodowlanego w procesie początkowej fazy przyrostu biomasy mikroglonów. Etap I (hodowla standardowa STD) prowadzono do momentu uzyskania koncentracji biomasy >1500 mg/dm 3 .…”

“…), azot azotanowy V (N-NO 3-), azot azotanowy III (N-NO 2-), fosfor całkowity (P Tot. ), ortofosforany (PO 4 3-) oraz pH. W celu określenia tempa przyrostu biomasy wykorzytywano sondę Zolitax firmy Hach Lange (Niemcy) umieszczoną w medium hodowlanym w całym okresie hodowli zarówno w I i II etapie badawczym.…”