Nutritional status regulates algicidal activity of Aeromonas sp. L23 against cyanobacteria and green algae

Abstract

Algicidal bacteria have received broad acceptance as an ecofriendly tool for controlling harmful algal blooms. However, their practical application is still limited to the lab-scale tests due to the complex alga–bacterium interactions in different nutrient statuses. In this study, the Aeromonas sp. L23 that exhibit relatively wide-spectrum in algicidal activity was isolated from a eutrophic agricultural lake. The physiological response of cyanobacteria and green to the algicidal activity under varied nutritional status were studied in an alga-bacterial co-culture. The algicidal activities of L23 against Microcystis aeruginosa UTEX LB 2385, Microcystis aeruginosa NHSB, Anabaena variabilis AG10064, Scenedesmus quadricauda AG10003, and Chlorella vulgaris AG10034 were 88 ± 1.2%, 94 ± 2.6%, 93 ± 0.5%, 82 ± 1.1%, and 47 ± 0.9%, respectively. The L23 cells had low algicidal activity in cell pellet (3%–9%) compared with the cell-free supernatant (78%–93%), indicating that the activity is induced by extracellular substances. Adding glucose, NaNO3, NH4Cl, and KH2PO4 to the co-culture raised the algicidal activity of the L23 against green algae by 5%–50%. Conversely, a 10%–20% decrease in activity occurred against the target cyanobacteria except M. aeruginosa UTEX LB 2385. These results indicated that the interspecific algicidal activity changes according to the nutritional status, which means that the alga-bacterium interaction will be more complex in the field where the nutritional status changes from time to time.

Simultaneous biodegradation of harmful Cylindrospermopsis raciborskii and cylindrospermopsin toxin in batch culture by single Bacillus strain

“…clay and ultrasonication), chemical methods (chemical substances), and biological methods using algicidal microorganisms (Shao et al 2013). However, physical and chemicals methods have signi cant disadvantages, where physical methods are not comprehensive and high energy cost and chemical methods can cause secondary pollution leading to the collapse of aquatic environments (Nishu et al 2019). Biological methods, on the other hand, are relatively cost effective with low risk and could be considered a promising approach for bioremediation of cyanobacterial blooms in water sources (Hou et al 2019).…”

“…Some of these microorganisms exhibit strong antagonistic effects on these blooms (Li et al 2011;Van Wichelen et al 2016), and thereby they could be exploited in bio-controlling and bioremediation of harmful cyanobacteria in water bodies. Numerous studies have been made on anti-cyanobacterial activity of heterotrophic bacteria and their degrading capabilities of cyanotoxins (Ndlela et al 2018;Nishu et al 2019;Weiss et al 2019;Massey and Yang 2020). However, most of these studies have concentrated mainly on one cyanobacterial species (M. aeruginosa) and one cyanotoxin type (microcystin).…”

Cyanobacterial Harmful Algal Blooms in Aquatic Ecosystems: A Comprehensive Outlook on Current and Emerging Mitigation and Control Approaches

“…The use of bacteria to control toxic blooms was proposed [ 157 ]. One example is Aeromonas veronii , which is often found in association with Microcystis colonies [ 158 , 159 , 160 ]. Spent media from A. veronii isolated from Microcystis sp.…”

Microfluidic and mathematical modeling of aquatic microbial communities

“…Also, increasing temperature and light intensity were shown to favor Dolichospermum flos-aquae in the competition against M. aeruginosa [105]. In addition, abiotic factors could also regulate the equilibrium of the vitamin B 12 -mediated mutualism of phytoplankton and bacteria [9,106], as well as the antagonistic algicidal behavior of bacteria [107].…”