Potential of Secondary Metabolite from Marine Heterotrophic Bacteria against Pathogenic Bacteria in Aquaculture

Abstract

Marine bacteria including heterotrophic bacteria are the most numerous organisms in nature and are capable of producing secondary metabolites. The secondary metabolite produced is a molecular compound produced from the secondary metabolic process, generally can be in the form of antibiotics, enzyme inhibitors, toxins, growth regulators, hormones, and insecticides. This study aims to examine the inhibitory ability of secondary metabolites of heterotrophic bacteria to the activity of pathogenic bacteria Aeromonas hydrophilla, Pseudomonas aeruginosa, and Vibrio alginolyticus. Around 10 heterotrophic bacterial isolates from the Marine Microbiology Laboratory collection, Fisheries and Marine Sciences Faculty, University of Riau was tested on pathogenic bacteria based on the Kirby-Bauer disk diffusion method. The results showed that all heterotrophic bacterial isolates were capable of inhibiting the growth of pathogenic bacteria such as A. hydrophilla (P), P. aeruginosa (Q), and V. alginolyticus (R). Vagococus fluvialis isolates are the best heterotrophic bacterial isolates in producing secondary metabolites compared to 9 other isolates. Where the clear zone formed is wider, that is 12.35 mm with the results of the activity test of 1877.78 mm2/ml. Based on the results, the heterotrophic bacteria are capable of producing secondary metabolites that inhibit the growth of pathogenic bacteria.

Biodiversity of Escherichia coli bacterial resistance to multidrug isolated on the Dumai coast of Indonesia

“…The density of E. coli at the 5 stations in Dumai seawater has exceeded the Ministry of the Environment standards (Figure 1), with the lowest value at station 5 (2.37 x 10 2 CFU/100 mL), which was identified as an area far from anthropogenic pollution. However, the density of E. coli at stations 2 and 3 (1.1 x 10 3 CFU/100 mL), known as an area prone to anthropogenic pollution (Feliatra et al 2020;Feliatra et al 2021), showed a higher coliform count because of the location near the harbor and densely settlements. Conversely, station 4 (7.45 x 10 2 CFU/100 mL) features a mangrove habitat, while station 1 (4.23 x 10 2 CFU/100 mL) is an industrial area (Lukistyowati et al 2019).…”

“…The results showed a single band for all samples at a size of around 1500 bp in 1% agarose gel (Figure 3). The 16S rRNA gene is the highly conserved region to identify the diversities in prokaryotic organisms and evolutionary relationships between prokaryotic strains (Mardalisa et al 2020).…”

Natural Biota’s Contribution to Cultured Aquatic Animals’ Growth in Aquaculture Cannot Be Ignored

“…In addition to basic nutrients provided by bacteria, they (Vibrio sp., Bacillus sp., and Talassobacter utilis) also produce various kinds of enzymes such as amylase, protease, cellulase, and lipase (improving the digestion and metabolism of cultured aquatic animals and enhancing their ability of stress resistance and health) and secondary metabolites [111,113,114]. For example, as a probiotic bacterium, B. subtilis increases the digestion and assimilation of nutrients by aquatic animals and secretes antimicrobial compounds, preventing pathogens' development and improving the water environment [115,116].…”

Molecular properties of postbiotics and their role in controlling aquaculture diseases

“…Nisin Z was utilized as an agro in boiled shrimp since this produces Lactococcus lactis KT2W2L, a brackish water organism that fights numerous foodborne infections. L. lactis infections in their environment (Dailin et al, 2019;Feliatra et al, 2020;Puccetti et al, 2020).…”

“…The use of postbiotic is one of the most common and effective disease management techniques in fisheries. These bacteria are less toxic and are used for handling infections in their environment (Dailin et al, 2019; Feliatra et al, 2020; Puccetti et al, 2020).…”