EXTRACTIVE AND ENZYMATIC ANALYSES FOR LIMITING OR SURPLUS PHOSPHORUS IN ALGAE (original) (raw)
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Luxury phosphorus uptake in microalgae
Journal of Applied Phycology, 2019
Phosphorus (P) is central to storing and exchange of energy and information in cells including those of microalgae. The overwhelming majority of microalgae are naturally acclimated to low-P environments; hence, they are capable of taking up and storing P in large amounts whenever it becomes available. The ability to take up more P than necessary for immediate growth is termed Bluxury uptake.^Understanding this phenomenon constitutes a crucial insight into nutrient-driven processes in natural algal communities such as harmful algal blooms, as well as into the operation of algae-based technologies for sustainable usage of P such as recycling of the nutrient from wastewater to biofertilizers. The bulk of P acquired during luxury uptake is stored in the form of inorganic polyphosphate, the compound with nearly ubiquitous presence and multifaceted function in the cell. Although seminal works on luxury P uptake and polyphosphate metabolism were carried out fifty years ago, application of modern Bomics^approaches and advanced imaging microscopy techniques enabled obtaining a deeper mechanistic insight into these processes. Nevertheless, our knowledge about luxury P uptake remains much more limited in comparison with that about P shortage and mechanism tolerance to this stress in microalgae. In this review the knowledge of luxury P uptake originating from classical phycological and biochemical methods is confronted with the recently obtained understanding of molecular mechanisms of P transport to the cell, polyphosphate biosynthesis, regulation, and genetic control of these processes. Biotechnological implications of the knowledge about luxury P uptake accumulated to date are discussed in the context of algae-based approaches to sustained usage of nutrients and industrial cultivation of microalgae.
Green Algae as a Way to Utilize Phosphorus Waste
Journal of Ecological Engineering, 2021
The possibility of using phosphorus-containing wastewater as a raw material for the cultivation of the green algae strain Chlorella vulgaris ASLI-1 can represent an effective processing of phosphorus-containing by-products. A laboratory experiment was made to study the effect of the concentration of phosphorus-containing wastewater on the biomass density of the green alga strain Chlorella vulgaris ASLI-1. Three weeks after sowing, we measured the biomass density of algae in various components of the phosphorus-containing wastewater. Compared to the control (distilled water), the addition of phosphorus-containing wastes did not adversely affect the culture of green algae, with the exception of a 20% medium where algal cells were discolored and had a low biomass density, 104 CFU. However, more research is needed to better study the response of green algae to phosphorus-containing waste, to determine the amount of phosphorus in cells and solution. In addition, evaluate the agronomic efficiency of the Chlorella vulgaris ASLI-1 strain, cultivated on phosphorus-containing waste, when applying fertilizers for growing vegetables.
Marine Ecology Progress Series, 1998
Alkaline phosphatase (AP) activity in marine and freshwater phytoplankton has been associated with phosphorus (P) limitation whereby the enzyme functions in the breakdown of exogenous organic P con~pounds to utilizable inorganic forms. Current enzyme assays to determine the P status of the phytoplankton measure only the AP activity of the whole community and do not yield information on ~ndiv~dual species. A new insoluble fluorogenic substrate for AP, termed ELF (Enzyme-Labeled Fluorescence), yields a stable, highly fluorescent precipitate at the site of enzyme act~vity and thus has the capability to determine the P status of indimdual cells. In t h~s study, ELF was utilized for in situ detection and quantification of AP in marine phytoplankton cultures and a comparison was made between the insoluble ELF substrate and several soluble AP substrates [3-0-methylfluorescein phosphate (MFP), 3,6-fluorescein diphosphate (FDP) and Attophos]. Non-axenic batch cultures of Alexandrium fundyense, Arnphidln~um sp, and Isochrysis galbana were grown in different media types using orthophosphate as an inorganic source and sodium-glycerophosphate as an organic source, with final phosphate concentrations ranging from 38.3 to 3 p M (i.e. f/2, f/40, f/80, plus ambient P). Epifluorescence microscopy was used to determine if and where the cells were labeled with ELF, while flow cytometry was used to quantify the amount of ELF retained on individual cells. The detection of the soluble substrates utilized a multiwell fluorescence plate reader (CytofluorTh4). Only cells grown in low phosphate concentrations (f/40, f/80) exhibited the bright green fluorescence signal of the ELF precipItate. This signal was always observed for P-starved Amphidiniurn sp. and I galbana cells, but was seen in some A, fundyense cells only during the late stationary phase. Cells grown in high phosphate concentrations (i.e. at f/2 levels) showed no ELF fluorescence. Slightly positive soluble substrate assays suggest that these species may have produced small amounts of AP constitutively that were not detected with the precipitable substrate. Similar results were obtained when the cultures were analyzed by flow cytometry. Except for A. fundyense, cells grown In low phosphate concentrations showed high ELF fluorescence. However, no positive ELF fluorescence was detected with the Cytofluor for all 3 species due to lack of instrument sensitivity. Comparable analysis using the soluble substrates MFP, FDP, and Att~phos-l-~' on the Cytofluor showed little activity for A , fundyense, but high fluorescence for P-starved Amphldiniun? sp. and I. galbana. Insoluble ELF thus provides a means to detect and quantify AP in individual cells using visual observations or flow cytometry. This technique offers a new level of resolution and sensitivity at the single cell level that can provide insights into the P nutrition of phytoplankton and other microorganisms in natural waters. KEY WORDS. Phytoplankton. Phosphorus limitation. Alkaline phosphatase. Phosphorus. ELF .
International Review of Hydrobiology, 1979
The limiting factor in the water of LakeBalaton was calculated by means Of VERDUIN'S equation. If only the orthophosphate-phosphorus concentration is inserted into the equation, phosphorus is the primary limiting factor. If, however, total phosphorus is considered, the factor intensity of nitrogen will be the least, i. e. nitrogen will be the primary limiting-factor of plant growth. According t o measurements during 1976, average values for the total dissolved phosphorus and orthophosphatephosphorus content of Balaton Lake water were 15,66 mg/m3 and 7.66 mg/m3, respectively. Experiments with the algal strain Scenedesmus obtusiusculus CROD. (Chlorophyceae, Chlorococcales) were designed to test the availability of the condensed phosphorus form for the algae. The experiments were performed partly with synthetic polyphosphates, partly, with polyphosphates isolated from Balaton Lake water. The results showed, contrary to our expectations, that phosphates present in the condensed form (irrespective of their structure and degree of condensation) were not utilized by the algae under sterile conditions, i. e. in the absence of bacterial activity. In the light of the above it is recommended t o consider only orthophosphate-phosphorus when calculating the limiting factor.
Поступила в редакцию 28.11.2016 г. Принята к публикации 30.03.2017 г. Filamentous green algae (FGA) may reach high biomass and play a very important functional role in productivity and nutrient cycling in the different water bodies. Their extracellular alkaline phosphatase activity may be an important player in the phosphorus cycle. Currently, there is intensive development of green algae in various freshwater and marine water bodies, which creates problems for people's activities and necessitates its investigation. Filamentous green algae in four Chinese and Crimean (Russia) shallow freshwater ponds were in focus of this study. The dissolved phosphorus fraction in pond water, algal pigment level, activity and kinetic properties of alkaline phosphatase were evaluated in water column and cell membrane of filamentous green algae. Microalgal taxa were identified in the plankton samples. Species composition and density of FGA in the studied ponds were different. Two ponds had more than 50 % coverage of a water surface by FGA and its wet biomass more than 100 g · m −2. Two others were with wet biomass less than 2 g · m −2. In ponds with low FGA biomass, the soluble reactive phosphorus concentration exhibited considerably low level with less than 10 µg · L −1 , and the dissolved organic phosphorus comprised the largest phosphorus fraction, averaging 23.1 µg · L −1 and ranged from 20.8 to 25.4 µg · L −1. However, in ponds with high FGA biomass, particulate phosphorus was the major component, which contributes 45.8 % and 56.7 % of total phosphorus, respectively. Size fractionation of extracellular alkaline phosphatase activity in water column expressed spatial heterogeneity, which corresponded with biomass of FGA. The response of extracellular alkaline phosphatase activity to different phosphate concentration in water column was completely distinct from that in the cell membrane of FGA, the last of which represented the significantly inhibition effect to high phosphate concentration. The significant inhibition of alkaline phosphatase activity in cell membrane of FGA by phosphate in water may validate that FGA growth was limited by phosphorus. The contradiction between a low concentration of soluble reactive phosphorus and high FGA biomass may indicate that there was high speed nutrient cycling, probably, due to the alkaline phosphatase activity. Excreting exo-alkaline phosphatases, FGA, microalgae and bacteria accelerate phosphorus cycling through different mechanisms, and this may increase their development. In ponds with high FGA biomass, many of bacteria are responsible for regeneration of nutrients, which then consuming by FGA. Those bacteria also may concurrently restrict a microalgae development, such as unicellular Chlorophyta species. As an example, Cladophora provides habitat for different species of epibionts (bacteria and microalgae, primarily diatoms), and sustains of strong mutualistic alga-bacterium interactions. Therefore, the problem of excessive FGA growth should not be considered in isolation, but in a whole-ecosystem context.