Seaweed Bioactive Compounds against Pathogens and Microalgae: Potential Uses on Pharmacology and Harmful Algae Bloom Control

Abstract

Cyanobacteria are found globally due to their adaptation to various environments. The occurrence of cyanobacterial blooms is not a new phenomenon. The bloom-forming and toxin-producing species have been a persistent nuisance all over the world over the last decades. Evidence suggests that this trend might be attributed to a complex interplay of direct and indirect anthropogenic influences. To control cyanobacterial blooms, various strategies, including physical, chemical, and biological methods have been proposed. Nevertheless, the use of those strategies is usually not effective. The isolation of natural compounds from many aquatic and terrestrial plants and seaweeds has become an alternative approach for controlling harmful algae in aquatic systems. Seaweeds have received attention from scientists because of their bioactive compounds with antibacterial, antifungal, anti-microalgae, and antioxidant properties. The undesirable effects of cyanobacteria proliferations and potential control methods are here reviewed, focusing on the use of potent bioactive compounds, isolated from seaweeds, against microalgae and cyanobacteria growth.

Trends in Seaweed Extract Based Biostimulants: Manufacturing Process and Beneficial Effect on Soil-Plant Systems

“…Seaweed extracts (SE) are perfect examples of such rich composition. Additionally to minerals and polysaccharides, SE may also contain, depending on processing methods, phytohormones, cytokinins, vitamins, polyphenols, antimicrobial agents, and several other compounds of agronomical value [83][84][85][86][87]. Consequently, unraveling possible mechanism of action is often delicate and involve multi-disciplinary approaches through making use of sophisticated technics as to grasp the specific effect of SE at both the metabolic and genetic level (Figures 4 and 5) ( Table 2).…”

Assessing risks and mitigating impacts of harmful algal blooms on mariculture and marine fisheries

“…For example, nutrient enrichment can be managed through the use of 'extractive' shellfish and macro-algal species. Furthermore, restoration of coastal habitats, for example with seagrasses that harbour algicidal bacteria (Inaba et al 2019), or cultivation of seaweeds that secrete algicidal chemicals (Zerrifi et al 2018), can also help mitigate against HABs. This follows Ecosystem Approaches to Fisheries and Aquaculture (EAF/EAA) (Soto & Aguilar-Manj arrez 2009;FAO, 2018), which cover three main aspects: (i) minimising environmental impacts and waste; (ii) sustaining wider ecosystem functions and services; and (iii) promoting human well-being and equity among marine stakeholders.…”

“…suspended bivalve shellfish and macroalgae, and benthic deposit feeders) to remove/reuse waste nutrient material discarded from the culturing of 'fed' species (finfish and crustaceans) thereby providing a self-sustaining and more productive food web ( Figure 2) (Soto 2009;Troell et al 2009;Chopin et al 2012). Macroalgae can also play a direct role in inhibiting the growth of microalgae, including HAB species, through competition for nutrients (Soto 2009;Holdt & Edwards 2014), inhibitory allelopathy (Tang & Gobler 2011;Ben Gharbia et al 2017;Zerrifi et al 2018), and/or by reducing light penetration (Zhou et al 2006;Wang et al 2007;Yang et al 2015).…”

Seaweeds as nutraceuticals for health and nutrition

“…In the last three decades, interest has grown in seaweeds as nutraceuticals, or functional foods, which gave dietary benefits beyond their macronutrient content. In addition, seaweed has been mined for metabolites with biological activity, to produce therapeutic products (Davis & Vasanthi 2011;Zerrifi et al 2018). The paradox of obesity concurrent with mineral and vitamin deficiency has become a health epidemic in developed regions such as Europe, the USA, and Australia (WHO 2019).…”