Biochemical and Molecular Aspects of Phosphorus Limitation in Diatoms and Their Relationship with Biomolecule Accumulation

Abstract

Diatoms are the most abundant group of phytoplankton, and their success lies in their significant adaptation ability to stress conditions, such as nutrient limitation. Phosphorus (P) is a key nutrient involved in the transfer of energy and the synthesis of several cellular components. Molecular and biochemical mechanisms related to how diatoms cope with P deficiency are not clear, and research into this has been limited to a few species. Among the molecular responses that have been reported in diatoms cultured under P deficient conditions is the upregulation of genes encoding enzymes related to the transport, assimilation, remobilization and recycling of this nutrient. Regarding biochemical responses, due to the reduction of the requirements for carbon structures for the synthesis of proteins and phospholipids, more CO2 is fixed than is consumed by the Calvin cycle. To deal with this excess, diatoms redirect the carbon flow toward the synthesis of storage compounds such as triacylglycerides and carbohydrates, which are excreted as extracellular polymeric substances. This review aimed to gather all current knowledge regarding the biochemical and molecular mechanisms of diatoms related to managing P deficiency in order to provide a wider insight into and understanding of their responses, as well as the metabolic pathways affected by the limitation of this nutrient.

Enhancement of Biomass Production of Diatom Nitzschia sp. S5 through Optimisation of Growth Medium Composition and Fed-Batch Cultivation

“…As expected, nitrogen limitation had the strongest impact on total chlorophyll content compared to silicon and phosphorus. Nitrogen is a structural component of chlorophyll molecules; therefore, nitrogen stress might decrease light harvesting and photosystem II activity efficiency, resulting in reduced photosynthetic rates [ 40 , 59 ]. Relatively high chlorophyll content of 2.31% was obtained in biomass grown in the absence of a phosphorus source.…”

Isolation of phosphorus-hyperaccumulating microalgae from revolving algal biofilm (RAB) wastewater treatment systems

“… Dyhrman et al (2012) discovered that even under low P, a condition known to inhibit polyP synthesis in most microalgae, the diatom Thalassiosira pseudonana increased polyP synthesis. Further research into P metabolism in diatoms is needed to fully understand and exploit these unusual polyP dynamics ( Lovio-Fragoso et al, 2021 ). The screening data presented in this study indicate that diatoms may possess an enormous amount of unexplored potential as tools to achieve a circular nutrient economy.…”

Bioprospecting of Microalgae Isolated from the Adriatic Sea: Characterization of Biomass, Pigment, Lipid and Fatty Acid Composition, and Antioxidant and Antimicrobial Activity

“…Under stressful conditions, carbon flux is redirected towards the production of energy reserves. Growth under nutrient limitation (e.g., nitrogen, phosphorus, and silicon) in the presence of an excess carbon source enables the accumulation of carbohydrates and/or lipids [71][72][73][74][75]. Due to a high protein content, all studied strains of microalgae and cyanobacterium could be used as food and feed supplements.…”