Effect of nitrogen feast–famine cycles and semi‐continuous cultivation on the productivity of energy‐rich compounds by Scenedesmus obtusiusculus AT‐UAM

Abstract

BACKGROUND Nitrogen (N) limitation is the most common strategy used to accumulate energy‐rich compounds in microalgae. However, this condition reduces the microalga growth rate and biomass, lipid and carbohydrate productivities. In this work, a semi‐continuous operation strategy combined with N feast–famine cycles were investigated in order to increase the lipid, carbohydrate and biomass contents in the microalga Scenedesmus obtusiusculus AT‐UAM. RESULTS Growth and lipid productivity were evaluated in a flat‐panel photobioreactor (FP‐PBR) under controlled conditions, through 72 and 24 h N feast–famine cycles at different N concentrations (6, 12 and 24 mg N L−1). The highest accumulation of microalgal biomass, lipid and carbohydrate (550 ± 28, 139 ± 4 and 198 ± 7 mg L−1 d−1) was obtained for 24 h cycles at 12 mg N L−1 and were up to ~2.4 times compared to that of 72 h N feast–famine cycles. This strategy was also applied in a bubble column photobioreactor (BC‐PBR) located in a greenhouse. Here, biomass productivities obtained under a semi‐continuous operation for 24 h N feast–famine cycles with 6 and 12 mg N L−1 were 536 ± 27 and 667 ± 33 mg L−1 d−1, respectively. The maximum productivity of lipid and carbohydrate reached 142 ± 10 and 169 ± 14 mg L−1 d−1 with 12 mg N L−1, respectively. CONCLUSION The studied N feast–famine cycles and semi‐continuous operations increased the productivity of biomass and lipids in S. obtusiusculus AT‐UAM. © 2021 Society of Chemical Industry (SCI).

Revisiting algal lipids and cellular stress-causing strategies for ameliorating the productivity of suitable lipids of microalgae for biofuel applications

“…The semi-continuous strategy proved to efficient as it relies on optimal environmental stress (e.g., nitrogen limitation) with suitable cycle time for providing sufficient nutrients and cost-effective production of lipids by ameliorating lipid productivity; thus, it can be considered as highly potential and promising for large scale production. 205 Generally, lipid accumulation occurs in the stationary phase of growth of microalgae, wherein nutrients will be limited. Thus, the optimized biomass will not necessarily result in higher lipid productivity either in the case of nutrient limitation applied for whole cultivation duration or sufficient nutrients provided during all the growth stages.…”

Special Issue: biotechnology advances in Latin America

“…Amaya-Chantaca et al 14 showed the potential of pomace from the winemaking industry as a fermentation substrate for the extraction of phenolic compounds in submerged and solid-state fermentation using Aspergillus niger GH1 as a biological model. Gorry and coworkers 15 reported the effect of nitrogen feast-famine cycles on microalgae biomass production and the accumulation of lipids and carbohydrates, which are critical parameters for the subsequent production of renewable fuels from the resulting microalgal biomass. Méndez-González et al 16 showed that addition of spherical-style packing improves the production of Metarhizium robertsii conidia, which are part of commercial formulations for insect pest control.…”