Effect of nitrogen deficiency on the physiology and biochemical composition of microalga Scenedesmus rotundus‐MG910488

Abstract

The present investigation ascertains the impact of gradient concentrations of sodium nitrate on the physiology and biochemical composition of isolated microalga Scenedesmus rotundus-MG910488. The concentrations of nitrate were selected as 0, 3.5, 7.0, 10.5, 14.0, and 17.6 mM/L in BG 11 medium. The lower concentrations of nitrogen were found to be significantly decreasing the cell count and photosynthetic activity in the microalga as well as changing cell morphology.The amount of biomass, its productivity and lipid yield were significantly affected.The highest biomass of 689.15 ± 14.27 mg/L was achieved in the concentration of 17.6 mM/L with the biomass productivity of 38.28 ± 0.78 mg/L. The highest lipid accumulation of 41.46 ± 1.94% dry-cell weight was obtained at a concentration of 3.5 mM/L, whereas the lowest lipid accumulation of 29.22 ± 1.65% at the concentration of 17.6 mM/L sodium nitrate. The fatty acid composition determines the quality of the fuel, so the characterization of fatty acid methyl esters (FAMEs) was performed by GC, and the assessment of methyl esters of fatty acid confirmed the existence of palmitic acid, oleic acid, and linoleic acid, which are essential components suitable for biodiesel production. FTIR confirms the presence of FAME components by estimating the bending and stretching of functional groups.

Influence of environmental conditions on lipid accumulation by the alga Halochlorella rubescens

“…This observation also indicates that the absence of a nitrogen source alters the biosynthetic pathway to accumulate lipids. A study of Scenedesmus rofundus showed that high lipid content can be achieved under low nitrogen supply conditions (41.46 ± 1.94%) (Dixit 2019). Similarly, Ruangsomboon and Ganmanee (2013) reported that the highest lipid contents (20.3 ± 0.4% and 19.4 ± 0.4%) were obtained in nitrogen-and phosphorus-deficient media, respectively, for Scenedesmus dimorphus KMITL.…”

“…Phosphates are crucial for growth and development, the production of cellular components, fatty acid production, energy transport, respiration and photosynthesis (Yaakob et al 2020). A study of Scenedesmus rofundus showed that the highest lipid content (41.46±1.94%) was achieved under low nitrogen supply conditions (Dixit 2019). Scenedesmus bajacalifornicus BBKLP-07 achieved highest lipid content of 26.19% in cultivation under 25% CO2 (Patil and Katiwal 2016).…”

Effects of Different Nitrogen Concentrations on Co-Production of Fucoxanthin and Fatty Acids in Conticribra weissflogii

“…Furthermore, assimilation of various nutrients in the culture medium could lead to the production of various intracellular products, which could affect the content of biomass, pigments, and fatty acids [ 26 , 27 ]. Since different nitrogen concentrations have different accumulation conditions for various substances [ 28 , 29 ], the findings show that the changes in algal biomass were different from the changes in algal cell density.…”

Enhancement of Biomass Production in Colony-Forming Green Algae, Botryosphaerella sudetica, Under Mixotrophic Cultivation

“…Previously, biotic and abiotic stresses were applied to green algae to enhance the lipid content of a limited available biomass (Rashid et al, 2020;Ananthi et al, 2021). For example, control of the nitrogen supply and type of sources (e.g., nitrate) increased the ratio of lipids to the weight unit (Dixit et al, 2020;Encinas-Arzate et al, 2020;Zhang et al, 2020). Nevertheless, increased lipid content was not accompanied by a positive effect on biomass productivity (Araujo et al, 2020;Toumi and Politaeva, 2021).…”