Effects of nitrogen concentration and media replacement on cell growth and lipid production of oleaginous marine microalga Nannochloropsis oceanica DUT01

Abstract Background Crude glycerol as a promising feedstock for microbial lipid production contains several impurities that make it toxic stress inducer at high amount. Under stress conditions, microorganisms can accumulate l-proline as a safeguard. Herein, l-proline was assessed as an anti-stress agent in crude glycerol media. Results Crude glycerol was converted to microbial lipids by the oleaginous yeast Rhodosporidium toruloides CGMCC 2.1389 in a two-staged culture mode. The media was supplied with exogenous l-proline to improve lipid production efficiency in high crude glycerol stress. An optimal amount of 0.5 g/L l-proline increased lipid titer and lipid yield by 34% and 28%, respectively. The lipid titer of 12.2 g/L and lipid content of 64.5% with a highest lipid yield of 0.26 g/g were achieved with l-proline addition, which were far higher than those of the control, i.e., lipid titer of 9.1 g/L, lipid content of 58% and lipid yield of 0.21 g/g. Similarly, l-proline also improved cell growth and glycerol consumption. Moreover, fatty acid compositional profiles of the lipid products was found suitable as a potential feedstock for biodiesel production. Conclusion Our study suggested that exogenous l-proline improved cell growth and lipid production on crude glycerol by R. toruloides. The fact that higher lipid yield as well as glycerol consumption indicated that l-proline might act as a potential anti-stress agent for the oleaginous yeast strain.

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A Mathematical Model of Neutral Lipid Content in terms of Initial Nitrogen Concentration and Validation in Coelastrum sp. HA-1 and Application in Chlorella sorokiniana

BioMed Research International ◽

10.1155/2017/9253020 ◽

2017 ◽

Vol 2017 ◽

pp. 1-10 ◽

Cited By ~ 1

Author(s):

Zhenhua Yang ◽

Yue Zhao ◽

Zhiyong Liu ◽

Chenfeng Liu ◽

Zhipeng Hu ◽

...

Keyword(s):

Protein Synthesis ◽

Lipid Content ◽

Lipid Accumulation ◽

Nitrogen Concentration ◽

Lipid Production ◽

Lipid Synthesis ◽

Quantitative Relationship ◽

Chlorella Sorokiniana ◽

High Lipid ◽

Nitrogen Concentrations

Microalgae are considered to be a potential major biomass feedstock for biofuel due to their high lipid content. However, no correlation equations as a function of initial nitrogen concentration for lipid accumulation have been developed for simplicity to predict lipid production and optimize the lipid production process. In this study, a lipid accumulation model was developed with simple parameters based on the assumption protein synthesis shift to lipid synthesis by a linear function of nitrogen quota. The model predictions fitted well for the growth, lipid content, and nitrogen consumption of Coelastrum sp. HA-1 under various initial nitrogen concentrations. Then the model was applied successfully in Chlorella sorokiniana to predict the lipid content with different light intensities. The quantitative relationship between initial nitrogen concentrations and the final lipid content with sensitivity analysis of the model were also discussed. Based on the model results, the conversion efficiency from protein synthesis to lipid synthesis is higher and higher in microalgae metabolism process as nitrogen decreases; however, the carbohydrate composition content remains basically unchanged neither in HA-1 nor in C. sorokiniana.

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Isochrysis sp. IOAC724S, a newly isolated, lipid-enriched, marine microalga for lipid production, and optimized cultivation conditions

Biomass and Bioenergy ◽

10.1016/j.biombioe.2013.11.003 ◽

2014 ◽

Vol 60 ◽

pp. 32-40 ◽

Cited By ~ 13

Author(s):

Qian Liu ◽

Tong Pang ◽

Ling Li ◽

Jianguo Liu ◽

Wei Lin

Keyword(s):

Lipid Production ◽

Cultivation Conditions ◽

Marine Microalga

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Repeated Batch Fermentation Biotechnology for the Biosynthesis of Lipid and Gamma-Linolenic Acid byCunninghamella bainieri2A1

BioMed Research International ◽

10.1155/2014/831783 ◽

2014 ◽

Vol 2014 ◽

pp. 1-12 ◽

Cited By ~ 6

Author(s):

Marjan Ganjali Dashti ◽

Peyman Abdeshahian ◽

Wan Mohtar Wan Yusoff ◽

Mohd Sahaid Kalil ◽

Aidil Abdul Hamid

Keyword(s):

Linolenic Acid ◽

Glucose Concentration ◽

Batch Fermentation ◽

Nitrogen Concentration ◽

Lipid Production ◽

Ammonium Tartrate ◽

Gamma Linolenic Acid ◽

Harvesting Time ◽

Repeated Batch Fermentation ◽

Repeated Batch

The biosynthesis of biomedical products including lipid and gamma-linolenic acid (GLA) byCunninghamella bainieri2A1 was studied in repeated batch fermentation. Three key process variables, namely, glucose concentration, ammonium tartrate concentration, and harvesting time, were optimized using response surface methodology. Repeated batch fermentation was carried out by the cultivation ofCunninghamella bainieri2A1 in nitrogen-limited medium with various nitrogen concentration (1–4 g/L) and glucose concentration (20–40 g/L) at three time intervals (12 h, 24 h, and 48 h). Experimental results showed that the highest lipid concentration of 6.2 g/L and the highest GLA concentration of 0.4 g/L were obtained in optimum conditions, where 20.2 g/L glucose, 2.12 g/L ammonium tartrate, and 48 h harvesting time were utilized. Statistical results showed that the interaction between glucose and ammonium tartrate concentration had highly significant effects on lipid and GLA biosynthesis (P<0.01). Moreover, harvesting time had a significant interaction effect with glucose and ammonium tartrate concentration on lipid production (P<0.05).

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