[Objective] The aim was to study the effects of L-carnitine on population growth of Nannochloropsis oculata and Tetrahymena sp..[Method] When the concentration of L-carnitine was 0,50,100 and 1 000 mg/L,population den...[Objective] The aim was to study the effects of L-carnitine on population growth of Nannochloropsis oculata and Tetrahymena sp..[Method] When the concentration of L-carnitine was 0,50,100 and 1 000 mg/L,population densities of Nannochloropsis oculata and Tetrahymena were determined respectively.[Result] Adding high-dose L-carnitine had a significant inhibition effect on the population growth of Nannochloropsis oculata （P0.05）.Adding L-carnitine had a significant proliferation promoting effect on the population growth of Tetrahymena （P0.05）.[Conclusion] The research provides theoretical basis for the application of L-carnitine as feed additive in aquaculture.展开更多
The marine microalga Nannochloropsis sp.contains various elongases and desaturases that are critical for biosynthesis of polyunsaturated fatty acids.A full-length cDNA encoding a long-chain fatty acid elongase,named N...The marine microalga Nannochloropsis sp.contains various elongases and desaturases that are critical for biosynthesis of polyunsaturated fatty acids.A full-length cDNA encoding a long-chain fatty acid elongase,named Ns FAE,was cloned from Nannochloropsis sp..The open reading frame of Ns FAE(GenBank accession no.MF680548)consisted of 1068 bp and encoded a predicted protein of 355 amino acids with molecular mass 38.8 k Da.The deduced polypeptide showed 43%–44%identity to fatty acyl elongases from other algae.RT-PCR experiments indicated that the Ns FAE gene exhibited the highest expression in Nannochloropsis sp.at 72 h(i.e.,during the third growth stage)and the expression was significantly lower in the other four growth stages.Plasmid p Ns FAE-CRISPR and a recombinant DNA fragment(ADH1p-Ns FAE-CYCt)were transformed into Saccharomyces cerevisiae strain BY4742 using the CRISPR-Cas system.Yeast transformants containing Ns FAE produced three fatty acids not normally present in wild-type BY4742-linoleic acid,linolenic acid and eicosadienoic acid-indicating that Ns FAE encodes a functional elongase enzyme.展开更多
This study determined growth and lipid accumulation in Nannochloropsis sp. MASCC 11 cultivated at different pH, temperatures, and CO2 concentrations in 10-day period. The suitability for biodiesel production was also ...This study determined growth and lipid accumulation in Nannochloropsis sp. MASCC 11 cultivated at different pH, temperatures, and CO2 concentrations in 10-day period. The suitability for biodiesel production was also evaluated based on the fatty acid profiles of microalgae lipid. Nannochloropsis sp. MASCC 11 showed an excellent tolerance to acidic pH(as low as 4.0), high temperatures(at least 40℃), and high CO2 concentrations(5%-15%), which are major stressed conditions in flue gas. The highest algal biomass was acquired at pH of 9.0(0.44 g L^-1), a temperature of 35℃(0.63 g L^-1), and a CO2 concentration of 5%(2.27 g L^-1). Maximum lipid production was obtained at p H of 6.0(108.2 mg L^-1), a temperature of 35℃(134.6 mg L^-1), and a CO2 concentration of 5%(782.7 mg L^-1). Synthesis of polyunsaturated fatty acids(PUFAs) in biomass was stimulated under high CO_2 concentrations, remaining above 80% of total fatty acids, mainly composed of C16:3, C18:2, and C18:3. This led to the algae-based biodiesel having a lower oxidation stability, better cold flow properties, and other parameters such as its kinematic viscosity, cetane number, and specific gravity complied with ASTM or EN 14214 biodiesel specifications. Therefore, the improvement of oxidative stability needs to be considered before Nannochloropsis sp. MASCC 11 lipid can be used for biodiesel production, even if this species can grow well under stressful conditions.展开更多
基金Supported by National Natural Science Foundation of China(30671621)~~
文摘[Objective] The aim was to study the effects of L-carnitine on population growth of Nannochloropsis oculata and Tetrahymena sp..[Method] When the concentration of L-carnitine was 0,50,100 and 1 000 mg/L,population densities of Nannochloropsis oculata and Tetrahymena were determined respectively.[Result] Adding high-dose L-carnitine had a significant inhibition effect on the population growth of Nannochloropsis oculata （P0.05）.Adding L-carnitine had a significant proliferation promoting effect on the population growth of Tetrahymena （P0.05）.[Conclusion] The research provides theoretical basis for the application of L-carnitine as feed additive in aquaculture.
基金supported by the Basic Scientific Fund for National Public Research Institutes of China (No. 2016Q07)
文摘The marine microalga Nannochloropsis sp.contains various elongases and desaturases that are critical for biosynthesis of polyunsaturated fatty acids.A full-length cDNA encoding a long-chain fatty acid elongase,named Ns FAE,was cloned from Nannochloropsis sp..The open reading frame of Ns FAE(GenBank accession no.MF680548)consisted of 1068 bp and encoded a predicted protein of 355 amino acids with molecular mass 38.8 k Da.The deduced polypeptide showed 43%–44%identity to fatty acyl elongases from other algae.RT-PCR experiments indicated that the Ns FAE gene exhibited the highest expression in Nannochloropsis sp.at 72 h(i.e.,during the third growth stage)and the expression was significantly lower in the other four growth stages.Plasmid p Ns FAE-CRISPR and a recombinant DNA fragment(ADH1p-Ns FAE-CYCt)were transformed into Saccharomyces cerevisiae strain BY4742 using the CRISPR-Cas system.Yeast transformants containing Ns FAE produced three fatty acids not normally present in wild-type BY4742-linoleic acid,linolenic acid and eicosadienoic acid-indicating that Ns FAE encodes a functional elongase enzyme.
基金supported by the National Key Technology R&D Programme (No. 2011BAD14B04)。
文摘This study determined growth and lipid accumulation in Nannochloropsis sp. MASCC 11 cultivated at different pH, temperatures, and CO2 concentrations in 10-day period. The suitability for biodiesel production was also evaluated based on the fatty acid profiles of microalgae lipid. Nannochloropsis sp. MASCC 11 showed an excellent tolerance to acidic pH(as low as 4.0), high temperatures(at least 40℃), and high CO2 concentrations(5%-15%), which are major stressed conditions in flue gas. The highest algal biomass was acquired at pH of 9.0(0.44 g L^-1), a temperature of 35℃(0.63 g L^-1), and a CO2 concentration of 5%(2.27 g L^-1). Maximum lipid production was obtained at p H of 6.0(108.2 mg L^-1), a temperature of 35℃(134.6 mg L^-1), and a CO2 concentration of 5%(782.7 mg L^-1). Synthesis of polyunsaturated fatty acids(PUFAs) in biomass was stimulated under high CO_2 concentrations, remaining above 80% of total fatty acids, mainly composed of C16:3, C18:2, and C18:3. This led to the algae-based biodiesel having a lower oxidation stability, better cold flow properties, and other parameters such as its kinematic viscosity, cetane number, and specific gravity complied with ASTM or EN 14214 biodiesel specifications. Therefore, the improvement of oxidative stability needs to be considered before Nannochloropsis sp. MASCC 11 lipid can be used for biodiesel production, even if this species can grow well under stressful conditions.
