In Vitro Antibacterial Activity of Marine Microalgae Extract against Vibrio harveyi

Abstract

Marine microalgae may produce antibacterial substances. At the exponential phase of growth, four species of marine microalgae were examined for their potential to create secondary metabolites that limit the growth of Vibrio harveyi: Nannochloropsis oceanica, Chaetoceros gracilis, Isochrysis sp., and Thalassiosira weissflogii. V. harveyi is a pathogenic bacteria that can cause severe mortality and loss in aquaculture. Disc diffusion assay and co-culture assay were used to determine antibacterial activity. On TSA % NaCl media, the disc impregnated with microalgae and extracted with ethanol, methanol, saline water, and dimethyl sulfoxide (DMSO) was tested against V. harveyi at concentrations of 1.0 × 105, 106 and 107 CFU mL−1. The disc diffusion assay revealed that N. oceanica extracted with ethanol had the largest inhibitory zone against V. harveyi. Meanwhile, only N. oceanica, Isochrysis sp., and T. weissflogii reduced the growth of V. harveyi (105 CFU mL−1) in the co-culture assay (p < 0.05). The current findings reveal that the hydrophilic chemicals in microalgae extract have antibiotic activity against the highly virulent V. harveyi, which causes vibriosis, a serious disease in farmed fish and aquaculture cultivation around the world.

Chemical Composition and Antibacterial and Antioxidant Activities of Stem Bark Essential Oil and Extracts of Solanecio gigas

“…The bioactive compounds' antibacterial activity was assessed using a modified agar disk diffusion method [ 17 ]. The antibacterial activity of the samples was tested using bacteria from the American Type Culture Collection (ATCC), which included gram-positive bacteria like S .…”

“…e bioactive compounds' antibacterial activity was assessed using a modified agar disk diffusion method [17].…”

Bioactivity and Digestibility of Microalgae Tetraselmis sp. and Nannochloropsis sp. as Basis of Their Potential as Novel Functional Foods

“…The terpenoids, carotenoids, polyphenolic, and fatty acids contained in the extracts were suggested as the major factor responsible for the observed effects. More recently, the ethanolic extracts of N. oceanica were determined to exert inhibitory effects against Vibrio harveyi in an in vitro co-culture assay, although the responsible compounds were not identified [ 119 ]. The growth inhibitory effects on Vibrio anguillariim , and Vibrio salmonicida reported for extracts obtained from T. suecica were not associated with any specific compound [ 120 ].…”

Microalgal bioactive metabolites as promising implements in nutraceuticals and pharmaceuticals: inspiring therapy for health benefits

“…The extract of Nannochloropsis oceanica, Isochrysis sp. and Thalassiosira weissflogii showed antibacterial effect against Vibrio harveyi at 1.0 × 10 5 , 10 6 and 10 7 CFU mL −1 concentrations where N. Oceanica exhibited largest zone of inhibition (Jusidin et al 2022 ). Methanolic extract of Chlorella sp.…”