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Antifouling activity of bacterial extracts associated with soft coral and macroalgae from the Red Sea

Tunkal Rabab Ibrahim, Jamal Mamdoh T., Abdulrahman Idris, Pugazhendi Arulazhagan, Satheesh Sathianeson

Oceanological and Hydrobiological Studies

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2022

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Vol. 51, No. 4

325--336

EN

In marine environments where biofouling occurs and has an impact on the maritime economy and environment, compounds that inhibit the attachment, growth and survival of microorganisms in a biofilm complex as well as settlement of larvae are considered potential antifouling compounds. In this study, the extracellular metabolites from two surface- associated bacteria isolated from soft coral and macroalga were evaluated for antibiofilm and antisettlement activity. The bacteria were identified using 16S rRNA gene sequencing, and the culture supernatant extract of each strain was evaluated for antibiofilm activity. The compounds present in the extracts were analysed using GC-MS. The two bacterial strains were identified as Bacillus licheniformis MBR1 and Vibrio alginolyticus MBR4 for the isolates from soft coral and macroalgae, respectively. The extracts inhibited the growth of biofilm-forming bacteria, biofilm formation and barnacle larval settlement. The GC-MS analysis of the extract detected the presence of compounds such as tetrapentacontane, octadecanoic acid, 2,3-dihydroxypropyl ester, hexadecanoic acid, 2-hydroxy-1-(hydroxymethyl) ethyl ester and 17-pentatriacontene. The results of the study show that extracellular metabolites of the bacteria associated with marine organisms could be used as natural antifouling compounds to control biofouling.

2

A comparative study of biosynthesized marine natural-product nanoparticles as antifouling biocides

Abdelsalam Khaled Mahmoud, Shaltout Nayrah Aly, Ibrahim Hassan Abduallah, Tadros Hermine Ramzy Zaki, Aly-Eldeen Mohamed Abd-Elnaby, Beltagy Ehab Aly

Oceanologia

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2022

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No. 64 (1)

35--49

EN

In this study, biosynthesized nanoparticles using chitosan, Ulva fasciata, and Avicennia marina leaves extracts (A, B, and C, respectively), were evaluated as paint additives to control marine fouling on different substrates. These biocidal nanoparticle compounds were prepared using a green biosynthesis method. Their characterizations were conducted using Fourier-Transform Infrared spectroscopy and Transmission electron microscopy. Each nanoparticle compound was mixed with a prepared paint, resulting in three formulations for each (e.g. 1C, 2C, 3C), containing 20%, 40%, and 60% by weight. Painted PVC, wood, and steel with these nine paints, and the control were immersed in seawater for different periods. After two months of immersion, the least number of fouling species, (one species) was recorded on both the wood and steel panels that were coated with paint (1C). Meanwhile, after four months, the least numbers of fouling (four and six species) were recorded on wood and steel panels that were coated with paint (3C). After around seven months of immersion, the least numbers of fouling species (five and ten) were recorded on wood and steel panels that were coated with paints (1C and 3C), respectively. The steel panel coated with (3C), harbored ∼2% of the total number of barnacles found on the control, after 7 months of immersion. The superior antifouling agent efficiency of extract (C) nanoparticles can be attributed to its constituents of polyphenols, ammonium compounds, and high concentrations of alcohols, besides the presence of both aromatic and aliphatic amide and amide derivatives.

3

Fabrication and Characterization of Polyphenylsulfone/Titanium Oxide Nanocomposite Membranes for Oily Wastewater Treatment

Al-Jadir Thaer, Alardhi Saja Mohsen, Alheety Mustafa A., Najim Aya A., Salih Issam K., Al-Furaiji Mustafa, Alsalhy Qusay F.

Journal of Ecological Engineering

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2022

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Vol. 23, nr 12

1--13

EN

Polyphenylsulfone (PPSU) membranes are critical for numerous applications, including water treatment, oil separation, energy production, electronic manufacturing, and biomedicine because of their low cost; regulated crystallinity; and chemical, thermal, and mechanical stability. Numerous studies have shown that altering the surface characteristics of PPSU membranes affects their stability and functionality. Nanocomposite membranes of PPSU (P0), PPSU-1%TiO2 (P1), and PPSU-2% TiO2 (P2) were prepared using the phase inversion method. Scanning electron microscopy and thermal analysis were performed to determine the contact angle and mechanical integrity of the proposed membranes. The results showed that the membranes contained channels of different diameters extending between 1.8 μm and 10.3 μm, which made them useful in removing oil. Thermal measurements showed that all of the PPSU membranes were stable at a temperature of not less than 240 °C, and had good mechanical properties, including tensile strength of 7.92 MPa and elongation of 0.217%. These properties enabled them to function in a harsh thermal environment. The experimental results of oil and water separation and BSA solution fouling on membrane P2 showed a 92.95% rejection rate and a flux recovery ratio of 82.56%, respectively, compared to P0 and P1.

4

Effects of copper and cadmium on physiology and antifouling defense of the marine macroalga Ulva reticulata

Al-Khaldi Wejdan Ahmed, Al Solami Lafi, Satheesh Sathianeson

Oceanological and Hydrobiological Studies

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2021

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Vol. 50, No. 2

184--197

EN

Heavy metals are major stressors for benthic macroalgal communities in marine ecosystems. In this study, the effects of copper and cadmium on some physiological parameters along with antifouling defense of the marine macroalga Ulva reticulata were assessed under laboratory conditions. Macroalgal samples were treated with three concentrations (1 mg l−1, 3 mg l−1 and 5 mg l−1) of copper and cadmium for 2 and 7 days. After treatment, algal samples were analyzed for chlorophyll-a, carotenoid, total polyphenol and total antioxidant capacity. Also, algal extracts were tested against biofilm-forming bacteria strains to understand differences in antifouling activity. The results indicated that exposure of U. reticulata to copper and cadmium, on the one hand, induced protective mechanisms such as total phenol production and antioxidant capacity against metal stress and, on the other hand, reduced photosynthesis. While the extract obtained from control algal samples showed a strong inhibitory effect on the growth of biofilm-forming bacteria, treatment with heavy metals resulted in reduced antibiofilm activity. In general, the results revealed that exposure of macroalgae to heavy metals can affect antifouling defense traits in addition to changes in photosynthetic pigment content.

5

Warstwy chitozanowe osadzone elektroforetycznie jako potencjalne powłoki przeciwporostowe

Kaczorowski P., Baranowska J.

Inżynieria Materiałowa

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2015

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Vol. 36, nr 6

524--527

PL

Ważnym zagadnieniem w eksploatacji konstrukcji wodnych jest zabezpieczenie ich przed porastaniem porostami, algami lub grzybami. Do najczęściej stosowanych metod zabezpieczających należy malowanie farbami antyporostowymi z dodatkiem specjalnych chemikaliów, takich jak toksyczne związki miedzi, związki cyny lub biocydy. Obiecującą ekologiczną alternatywą do tego typu zastosowań są powłoki chitozanowe, stabilne w środowisku wodnym oraz zmniejszające tarcie. W pracy przedstawiono wstępne badania nad osadzaniem tego typu powłok metodą elektroforetyczną. Otrzymano powłoki, równomiernie pokrywające próbkę, chitozanowe o dobrej stabilności w wodzie.

EN

An important issue in the exploitation of water constructions is to protecting them against fouling lichens, algae or fungi. The most commonly used method of hedging should be covered with antifouling paints with the addition of special chemicals such as toxic copper compounds, tin compounds or biocides. Promising ecological alternative for this type of applications are chitosan coatings, stable in an aqueous environment and reducing the friction. The paper presents preliminary research on this type of coating deposition electrophoretic method. Received chitosan coating, with good stability in the water, that evenly cover the sample.

6

Exposure to chlorine affects the extracellular polymeric substance production and cell surface hydrophobicity in biofilm bacteria

Rathi R., Satheesh S.

Oceanological and Hydrobiological Studies

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2012

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Vol. 41, No. 4

17-24

EN

Chlorination is a common antifouling method adopted by industrial units to minimize the fouling growth on cooling systems. In the present study, the effect of sodium hypochlorite on extracellular polymeric substance (EPS) production, hydrophobicity, cell adhesion and viability of marine bacteria involved in biofilm formation were assessed in laboratory condition. Two bacterial strains, tentatively identified as Alteromonas sp. and Pseudomonas sp. isolated from the surface of seaweeds were used as test organisms for the present study. The bacterial cultures were treated with sodium hypochlorite at 25% of the minimum inhibitory concentration. Results showed considerable variation in the production of EPS, viable counts, hydrophobicity and adhesion ability of bacteria treated with sodium hypochlorite. In general, the present study indicated that chlorination affects some important characteristics involved in the biofilm formation and thereby reduces the adhesion rate on surfaces.