Effects of Nitrogen Forms and Supply Mode on Lipid Production of Microalga Scenedesmus obliquus

Abstract

Optimization of the microalgae culture conditions could significantly reduce the production costs of microalgae-derived biodiesel. In the current study, a new process of adding different forms using the multiple small-dose method was employed. The effects of different forms of nitrogen (NaNO3, NH4Cl, and CH4N2O) and their concentrations (0.1, 0.5, 1, and 2 mg L−1) on the growth and lipid production of Scenedesmus obliquus were studied. Algae density and lipid production increased with increasing nitrogen concentration for all different forms of nitrogen except NH4Cl. The Scenedesmus obliquus growth was promoted by adding NaNO3 and CH4N2O, but was inhibited by adding NH4Cl. Adding 2 mg N L−1 of CH4N2O daily yielded the highest cell density (1.7 × 107 cells mL−1) and lipid production (242.4 mg L−1). These conditions can thus maintain the biomass of Scenedesmus obliquus, increase its lipid accumulation, and decrease the costs of biodiesel production.

Influence of Nitrogen and Phosphorus on Microalgal Growth, Biomass, Lipid, and Fatty Acid Production: An Overview

“…Effect of different nitrogen concentrations (0, 36, 72, 144 and 288 mg/L) on the growth rate and biochemical composition Growth decreased in nitrogen-deficient conditions; in contrast, carbohydrates and fatty acids showed the highest value, 47% and 75%, respectively [7] Scenedesmus obliquus Various nitrogen concentrations' effect on growth and lipid production Lipid production increased with increasing nitrogen concentration; the highest cell density (1.7 × 10 7 cells/mL) and lipid production (242.4 mg/L) [33] Zhu et al [3] reported that Chlorella zofingiensis showed rapid growth in nitrogensufficient culture medium, whereas growth inhibition under nitrogen starvation conditions was observed. Upon nitrogen starvation, lipid accumulation increased greatly in C. zonfingiensis cells, which is desirable for biodiesel generation.…”

“…Nitrogen-deficient culture conditions produced two-fold lipids compared to nitrogen-sufficient medium as reported by Jia et al [ 30 ] and Pancha et al [ 29 ]. However, nitrogen depletion conditions can lead to the reduction of microalgae biomass productivity [ 33 ]. I. galbana was cultivated in different nitrogen concentrations to induced stress for lipid production.…”

Recommended turbulent energy dissipation rate for biomass and lipid production of Scenedesmus obliquus in an aerated photosynthetic culture system

“…The algae solution was centrifuged at 11,180×g for 6 min, and the algal residue was dried to constant weight at 60°C to collect dry algal matter. The lipid was extracted using the methanol-chloroform method described by An et al (2020). A precisely measured 100 mg of dried algae (W a ) was transferred into a 50 mL centrifuge tube, and 12 mL of a 1:2 chloroform-methanol solution was added.…”

Lignocellulosic Biomass as a Substrate for Oleaginous Microorganisms: A Review

“…Furthermore, it is possible that nitrogen limitation affects the lipid profile and several biochemical pathways of the cells [85][86][87].Therefore, new approaches, such as metabolic engineering, may be needed to increase the understanding of the effect of nitrogen on microalgae physiology and on the synthesis and accumulation of TGAs.…”