Changes of Extracellular Polymeric Substance (EPS) during Microcystis Aeruginosa Blooms at Different Levels of Nutrients in a Eutrophic Microcosmic Simulation Device

Abstract

The outbreak of cyanobacterial blooms in water can cause serious harm to water supply safety and human health, which has become one of the major water environmental problems in the present world. In this paper, the representative Microcystis aeruginosa blooms were studied by the eutrophic microcosmic simulation device between natural lake system and test in laboratory scale. Toxic Microcystis aeruginosa FACHB-905 and non-toxic Microcystis aeruginosa FACHB-469 were used to simulate algal blooms in different nutrient conditions. The study of stratified EPS extracted from different vegetative and growth stages of Microcystis aeruginosa showed that high nutritional conditions can induce Microcystis aeruginosa to produce more extracellular polysaccharides, while low nutrient conditions can affect the fluorescence components in the SL-EPS (Soluble EPS) of Microcystis aeruginosa. Furthermore, the proteins in TB-EPS (Tightly bound EPS) will gradually release to SL-EPS and LB-EPS (loosely bound EPS) during the bloom, which can decrease from 34% in the initial growth period to 20%. The tryptophan-like substances in SL-EPS and TB-EPS, and the humic-acid-like substances in SL-EPS have a significant impact on the Microcystis aeruginosa blooms. Finally, all these results are expected to be of use in the study of the algal blooming outbreak early warning and control problems.

Extracellular Polymeric Substances (EPS) as Microalgal Bioproducts: A Review of Factors Affecting EPS Synthesis and Application in Flocculation Processes

“…Wang et al (2020) suggest that proteins may be transferred from the inner layer (TB-EPS) to the outside of the cell (LB-EPS and SB-EPS). They also observed a decrease in protein content in TB-EPS in the death phase, whereas the protein content was comparable during the logarithmic growth phase in all EPS fractions [11].…”

Symbiotic relationship between filamentous algae (Halomicronema sp.) and extracellular polymeric substance-producing algae (Chlamydomonas sp.) through biomimetic simulation of natural algal mats

“…Generally, the EPS productivity of microalgae increases under stressful conditions, such as high light sources or temperatures ( Babiak and Krzemińska, 2021 ), and Wang et al (2019) reported that s-EPS production becomes active even in limited nutritional environments. In this study, Chlamydomonas sp.…”

“…affected the release of EPS. Wang et al (2019) explained that the production of b-EPS does not directly affect the weight of biomass; however, the stable protein content in b-EPS builds a crosslinked network to maintain the internal biological membrane structure, induces rapid biosynthesis of EPS polysaccharides, and enhances microbial adhesion. Arcila and Buitrón (2017) demonstrated that an increase in the protein/polysaccharide (PN/PS) ratio of EPS has a positive effect on the formation of flocs and granules in microalgae-bacteria aggregates.…”

Characteristics of Fluorescence Spectra, UV Spectra, and Specific Growth Rates during the Outbreak of Toxic Microcystis Aeruginosa FACHB-905 and Non-Toxic FACHB-469 under Different Nutrient Conditions in a Eutrophic Microcosmic Simulation Device

“…Although the daily climate changed and environmental conditions were different, the temperature, light intensity, wind speed, and weather were basically the same for each experimental jar in the sunroom. The nutrient ratios in the culture medium for bloom simulation of Microcystis aeruginosa and simulated culture device were the same as in our previous study [24]. A total of 330 temperature data were detected, with an average of 32.0 • C and a temperature range of 26.6-36.8 • C. And the light intensity ranges from 1300-60,500 Lux, with an average of 20,044 Lux.…”

“…Like ultraviolet spectroscopy, three-dimensional fluorescence spectroscopy can also obtain many indices at once. In addition to the humification index (HIX) and the freshness index (β:α) mentioned above, the excitation-emission matrix (EEM) contours and fluorescence intensity scores can also be obtained [24]. These two spectral analysis methods have high testing rates, can be set up for multi-channel instantaneous multi-point acquisition, and can provide output in real-time.…”