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

Abstract

Microalgae can be used as a source of alternative food, animal feed, biofuel, fertilizer, cosmetics, nutraceuticals and for pharmaceutical purposes. The extraction of organic constituents from microalgae cultivated in the different nutrient compositions is influenced by microalgal growth rates, biomass yield and nutritional content in terms of lipid and fatty acid production. In this context, nutrient composition plays an important role in microalgae cultivation, and depletion and excessive sources of this nutrient might affect the quality of biomass. Investigation on the role of nitrogen and phosphorus, which are crucial for the growth of algae, has been addressed. However, there are challenges for enhancing nutrient utilization efficiently for large scale microalgae cultivation. Hence, this study aims to highlight the level of nitrogen and phosphorus required for microalgae cultivation and focuses on the benefits of nitrogen and phosphorus for increasing biomass productivity of microalgae for improved lipid and fatty acid quantities. Furthermore, the suitable extraction methods that can be used to utilize lipid and fatty acids from microalgae for biofuel have also been reviewed.

Long-Term Cultivation of a Native Arthrospira platensis (Spirulina) Strain in Pozo Izquierdo (Gran Canaria, Spain): Technical Evidence for a Viable Production of Food-Grade Biomass

“…The lipid and carbohydrate content trends observed in this study are in line with the results of a previous study on A. platensis cultures operated semi-continuously under different phosphate concentrations in laboratory conditions, in which phosphorous starvation caused a significant increase of the carbohydrate content in the algal biomass coupled with a lower amount of lipids [80]. This is a different behaviour in comparison with other microalgae that either accumulate both carbohydrates and lipids or exclusively lipids under P starvation [81,82]. It is known that inorganic phosphorous allosterically inhibits ADP-glucose pyrophosphorylase, i.e., the main enzyme that controls carbohydrates synthesis in microalgae and cyanobacteria [80,83], and that both phosphorous depletion and decrease in light availability can lead to a reduction of the available ATP.…”

Deciphering role of technical bioprocess parameters for bioethanol production using microalgae

“…The synthetic metabolism of microalgae for rapid rate of growth, excessive biomass and biomolecules accumulation, could be improved with the change in certain cultivation conditions such as temperature, pH, nutrient concentration, light, CO 2 level and salinity. To date numerous studies have been reported that illustrates the individual as well as combined effect of different parameters for production of microalgae biomass ( Miranda et al, 2016 , Peng et al, 2020 , Yaakob et al, 2021 ; F. Yang et al, 2014 ). Faster growth rate and high biomass productivity are significant key feature of microalgal species for use in commercial purposes, as it favors robust growth over microorganism contamination in large scale outdoor facilities for cultivation of microalgae ( Tan & Lee, 2016 ).…”

“…High phosphate concentration coupled with high pH has resulted in significantly rapid growth rate and biomass productivity. Growth rate and phosphate concentration are directly correlated to biomass productivity of microalgae ( Yaakob et al, 2021 ).…”

“…Phosphorus is a requisite nutrient for growth and cell division of algae. Microalgae has high tendency to absorb phosphorus from medium and level of phosphorus uptake is linearly proportional to biomass production ( Fu et al, 2017 , Yaakob et al, 2021 ).…”

Production of Arthrospira (Spirulina) platensis Enriched in β-Glucans through Phosphorus Limitation

“…In terms of carbohydrate productivity (Figure 1b), the best results were obtained with 2 and 3 mg-P/L phosphorus concentration, which gave approximately 145-148 mg/L/d. One of the main challenges in cultivating microalgae and cyanobacteria under nutrient limited conditions is the trade-off between the accumulation of the target biomolecules triggered by the low availability of the nutrients and the subsequent reduction in biomass production [33]. The results of the present study demonstrate that the process of phosphorus limitation could be optimized in order to cultivate A. platensis in long-term cultivation processes by providing phosphorus at amounts that can support cell multiplication while at the same time triggering the down-synthesis of proteins and accumulation of carbohydrates.…”