Anti-Bacterial Adhesion Activity of Tropical Microalgae Extracts

Abstract

The evolution of regulations concerning biocidal products aimed towards an increased protection of the environment (e.g., EU Regulation No 528/2012) requires the development of new non-toxic anti-fouling (AF) systems. As the marine environment is an important source of inspiration, such AF systems inhibiting the adhesion of organisms without any toxicity could be based on molecules of natural origin. In this context, the antibiofilm potential of tropical microalgal extracts was investigated. The tropics are particularly interesting in terms of solar energy and temperatures which provide a wide marine diversity and a high production of microalgae. Twenty microalgal strains isolated from the Indian Ocean were studied. Their extracts were characterized in terms of global chemical composition by high resolution magic angle spinning (HR-MAS) and nuclear magnetic resonance (NMR) spectroscopy, toxicity against marine bacteria (viability and growth) and anti-adhesion effect. The different observations made by confocal laser scanning microscopy (CLSM) showed a significant activity of three extracts from Dinoflagellate strains against the settlement of selected marine bacteria without any toxicity at a concentration of 50 μg/mL. The Symbiodinium sp. (P-78) extract inhibited the adhesion of Bacillus sp. 4J6 (Atlantic Ocean), Shewanella sp. MVV1 (Indian Ocean) and Pseudoalteromonas lipolytica TC8 (Mediterranean Ocean) at 60, 76 and 52%, respectively. These results underlined the potential of using microalgal extracts to repel fouling organisms.

Unveiling antimicrobial activity of microalgae Chlorella sorokiniana (UKM2), Chlorella sp. (UKM8) and Scenedesmus sp. (UKM9)

“…Methanol extraction is an established and well-reported method to isolate active antimicrobial components from microalgae ( Patil and Kaliwal, 2019 , Zea-Obando et al, 2018 ). Table 3 shows the obtained ME from UKM8 and UKM9 were effective against a broader spectrum of Gram-positive and Gram-negative bacteria, which could be considered as promising antibacterial agents.…”

The Usefulness of Microalgae Compounds for Preventing Biofilm Infections

“…Curiously, the Chlorophyta phylum is known for its ability to synthesize a variety of bioactive compounds such as lipids and derivative polyunsaturated fatty acids (PUFAs). Specifically, two PUFAs, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), have demonstrated to exhibit antibacterial and antibiofilm properties [68,69]. However, in this study, their presence was not evident.…”

In Vitro Antibacterial Activity of Marine Microalgae Extract against Vibrio harveyi

“…The methanolic extract is a well-established and reported method to isolate active antimicrobial components from microalgae [37,38]. In another study, methanol was found to be the best organic solvent to obtain bioactive compounds from Dunaliella sp.…”