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The Persian Gulf is a transit point for a lot of crude oil at the international level. The purpose of this research is to compare two methods of biostimulation and bioaugmentation for degradation of sediments contaminated with crude oil in the Persian Gulf. In this research, six types of microcosms were designed (sediments of Khark Island). Some indicators, such as the quantity of marine bacteria, enzyme activity (catalase, polyphenol oxidase, and dehydrogenase), biodiversity indices, and the percentage of crude oil degradation were analyzed during different days (0, 20, 40, 60, 80, 100 and 120). The results of this research showed that the highest quantity of heterotrophic and crude oil-degrading bacteria to the sixth microcosm (stimulation–bioaugmentation), a combination of two methods bioaugmentation and biostimulation (3.9 × 106 CFU g−1). After crude oil pollution, the activity of catalase and polyphenol oxidase increased, and the dehydrogenase enzyme decreased. Bioaugmentation microcosm has the highest activity of enzymes among all studied microcosms. Predominant bacteria in each microcosm belonged to Cellulosimicrobium, Shewanella, Alcanivorax, and Cobetia. The highest degradation of crude oil is related to the stimulation–bioaugmentation microcosm. The statistical results of this research proved that there is a significant relationship between the type of method chosen for biodegradation with the sampling time and the quantity of marine bacteria. The results of this research confirm that crude oil pollution in the Persian Gulf sediments can be reduced by choosing the proper bioremediation method. [ABSTRACT FROM AUTHOR]

The Bacillus pumilus SG isolated from soil samples at the Persian Gulf was analyzed for its ability to produce biosurfactant. Various screening techniques were used for evaluating biosurfactant production and confirming biosurfactant presence in the culture supernatant. Most n-alkanes in the bacterial culture media were effectively degraded in the presence of biosurfactant acquired from the bacteria. The highest interfacial tension (IT) reduction (42 mN/m) was obtained at 24-h fermentation time (exponential phase) and did not change significantly afterwards. The glycolipid structure of the biosurfactant was revealed through NMR and FTIR spectroscopy analysis. Two-level factorial design was then applied for optimization of biosurfactant production, where a maximal reduction of culture broth IT (30 mN/m) acquired in the presence of crude oil (0.5%, v/v), NaNO3 (1 g/L), yeast extract (1 g/L), peptone (2 g/L) and temperature of 25 °C. The produced biosurfactant that exhibited a critical micelle concentration of 0.1 mg/ml was thermally stable. The glycolipid biosurfactant also displayed significant antibacterial activities against both Gram-positive and Gram-negative bacteria. The maximum inhibition of glycolipids biosurfactant was found against Acinetobacter strains (zone of inhibition, 45 mm). In addition, antibiofilm activities with a 50–90% biofilm reduction percent were indicated by the glycolipid biosurfactant. In conclusion, the glycolipid biosurfactant produced by B. pumilus SG revealed a wide range of functional properties and was verified as a good candidate for biomedical application. In conclusion, the glycolipid biosurfactant produced by B. pumilus SG showed a wide range of functional properties in this study, and in the case of further in vivo studies, it can be investigated a good candidate for biomedical applications such as use against biofilm or in pharmaceutical formulations. [ABSTRACT FROM AUTHOR]

The Persian Gulf is the most critical aquatic environment in the world. The relationship between marine animals and degrading bacteria not well understand. The purpose of this investigation is the description of symbiont crude oil-degrading bacteria in some sponges in the Persian Gulf. Marine sponges were collected from four stations at the Persian Gulf. Symbiont crude oil-degrading bacteria were isolated from marine sponges by enrichment in ONR7a medium after four subcultures. The isolated bacteria were identified by biochemical and molecular methods. The degradation of crude oil was determined by spectrophotometric, gravimetric, and GC-FID methods for each strain. In this study, 38 crude oil-degrading bacteria were isolated from 8 sponge samples. The efficient strains that had the highest crude oil degradation belonged to the genus Cellulosimicrobium, Shewanella, Alcanivorax and Cobetia. The GC-FID analysis confirmed that the strains IAUK3532, IAUK3537 and IAUK3519 exhibit maximum degradation of crude oil (respectively, 94.5%, 88.13% and 85%). It is observed that when the concentration of crude oil increased, the degradation decreased. It can be concluded from these results that the microbes that coexist in the sponges located at the Persian Gulf can degrade crude oil. These symbionts crude oil-degrading bacteria can be applied to decrease the oil pollution in the Persian Gulf. Also, the symbiotic relationship between sponges and crude oil-degrading bacteria increases sponge survival and contributes to the development of their colonies in the Persian Gulf. [ABSTRACT FROM AUTHOR]

BACKGROUND About 25,000 oil tankers are transported annually through the Persian Gulf in Iran. Therefore, oil pollution in this region is very high. Research on the use of marine bacteria to degrade crude oil has yielded good results in recent years. The present study investigates bacteria that are symbiotic with marine corals and their ability to degrade crude oil. Corals were collected from five regions in the Persian Gulf and enriched with decomposing bacteria in ONR7a culture. After biochemical and molecular identification of bacterial isolates, the ability of the strains to degrade crude oil by spectrophotometric, gravimetric, and Gas Chromatography‐ Mass Spectroscopy (GC‐MS) methods was investigated. RESULTS: Finally, 26 bacterial strains were identified from 5 coral samples. The efficient strains that had the highest crude‐oil degradation belonged to genera Cobetia, Shewanella, Alcanivorax, and Cellulosimicrobium. Strains IAUK3568, IAUK3568, IAUK3502, IAUK3531, and IAUK3552 exhibited a maximum degradation of crude oil of 93.5%, 88.13%, 87.24%, 85.17%, and 77.3%, respectively. CONCLUSION: The results showed that all bacterial isolates degrade medium‐chain alkanes better than long‐ and short‐chain alkanes. The data obtained in this study confirm that the corals of the Persian Gulf have the necessary bacterial diversity to decompose crude oil and, consequently, reduce pollution in this region. © 2021 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Sea anemones produce many biologically active compounds including neurotoxins, pore-forming toxins, phospholipases and proteinase inhibitors. The Persian Gulf is an unexplored environment and maybe a rich source of marine natural products. The aim of this study is screening and identification of bioactive metabolites from Stichodactyla haddoni (Haddon's sea anemone) collected at the Persian Gulf. The crude extract of the sea anemone (tentacle, disc and total body) was obtained by methanol solvent. The antibacterial assays were carried out by the disc diffusion method. The antibiofilm activity (biofilm formation, biofilm destruction and reduction of metabolic activity) of the sea anemone extracts was evaluated by microtiter plate method. The bioactive compounds were identified by GC–MS analysis. Data showed that the best antibacterial effect (relate to P. aeruginosa) is obtained from extracts of "total body" section. Values of minimum inhibitory concentration and minimum bactericidal concentration show that the maximum antibacterial activity takes place at 10–20 mg/ml concentration. Three parts of sea anemone exhibit different inhibition against biofilm of bacteria, in particular, inhibition of biofilm observed by the tentacle, disc and total body against P. aeruginosa, K. pneumonia and A. baumannii, respectively. Biofilm of P. aeruginosa was the most sensitive and the biofilm of B. cereus was the most resistant structure between all pathogenic bacteria. The best reduction in the metabolic activity was observed in P. aeruginosa and K. pneumonia among tested bacteria. Aliphatic compounds were predominant bioactive metabolites in this sea anemone. The marine animal and especially sea anemone produce useful bioactive compounds that can be used to prevent bacterial biofilm; application of bioactive materials, reported in this study, can be proposed for future studies. [ABSTRACT FROM AUTHOR]

Background: Sponges and sea anemones do not have specialized defense organs. Instead, they rival harmful microorganisms by producing certain compounds. These compounds can also be useful against some human pathogens. This study aimed to investigate the antimicrobial effects of bioactive products from these marine animals. Methods: Two species of sea anemone (Zoanthus sansibaricus and Cerianthus lloydii) and one species of sponge (Callyspongia sp.) were collected at the Persian Gulf. The active metabolites of these two marine animals were extracted by methanol and dichloromethane solvents. The antimicrobial activity of each extract was performed against six human pathogenic bacteria including: Pseudomonas aeruginosa, Acinetobacter baumannii, Bacillus cereus, Klebsiella pneumoniae, Escherichia coli, and Staphylococcus aureus, using disk diffusion and agar well plate methods. The MIC and MBC were determined. The inhibitory effect of these extracts on biofilm formation was also studied. Results: The effect of sponge extracts against planktonic forms of bacteria showed that the most sensitive bacteria to Callyspongia sp. extracts were K. pneumoniae and S. aureus. However, C. lloydii did not have any inhibitory effect on K. pneumoniae. The results of this study confirmed that both sponge and sea anemones extracts had sufficient effects against biofilm formation of pathogenic bacteria. However, Callyspongia sp. extracts had the lowest inhibitory effect against biofilm formation of P. aeruginosa. The highest inhibitory effect was observed on biofilm formation of K. pneumoniae. Conclusions: The Callyspongia sp sponge extract (Dichloromethane: Methanol) has an excellent antimicrobial effect against six pathogenic bacteria in planktonic and biofilm forms. There was a direct correlation between the increase in the concentration of sea anemones extracts and the inhibitory effect of biofilm formation. [ABSTRACT FROM AUTHOR]

Naphthalene is a ubiquitous pollutant of the marine environment, and naphthalene biodegradation has been receiving constant scientific consideration. For cleanup of aromatic contaminated sites, bioremediation methods are considered as economical and safe approaches for the marine environment. The aims of this research are isolation and characterization of naphthalene-degrading bacteria from some marine samples of the Persian Gulf. Fifty four naphthalene-degrading bacteria were isolated from marine samples (sediment and seawater) that are enriched in ONR7a medium with naphthalene as the only carbon source. Some screening tests such as growth at high concentration of naphthalene, bioemulsifier production and surface hydrophobicity were done to select the best and prevalent strains for naphthalene degradation. Determination of the nucleotide sequence of the gene encoding for 16S rRNA shows that these isolated strains belong to these genera: Shewanella , Salegentibacter , Halomonas , Marinobacter , Oceanicola , Idiomarina and Thalassospira . These strains can degrade half of the percentage of naphthalene in 10 days of incubation. This research is the first report on isolation of these genera from the Persian Gulf as naphthalene-degrader. [ABSTRACT FROM AUTHOR]

Symbiotic associations are complex partnerships that can lead to new metabolic capabilities and the establishment of novel organisms. The diversity of these associations is very broad and there are still many mysteries about the origin and the exact relationship between the organisms that are involved in a symbiosis. The aim of the present study is to find symbiotic crude-oil degrading bacteria in the mussels that collected from the Persian Gulf. Fifteen crude-oil degrading bacteria were isolated from Mactra stultorum mussel that collected from oil contaminated area at Persian Gulf. According to high growth rate on crude oil five strains were selected from 15 isolated strains for more study. Determination of the nucleotide sequence of the gene encoding 16S rRNA show that these isolated strains belong to: Alcanivorax dieselolei strain BHA25, Idiomarina baltica strain BHA28, A. dieselolei strain BHA30, Alcanivorax sp. strain BHA32 and Vibrio azureus strain BHA36. Analysis of remaining of crude oil by Gas Chromatography (GC) confirmed that these strains can degrade: 64%, 63%, 71%, 58% and 75% of crude oil respectively. [ABSTRACT FROM AUTHOR]

To date, little is known about existing relationships between mussels and bacteria in hydrocarbon-contaminated marine environments. The aim of this study is to find crude oil degrading bacteria in some mussels at the Persian Gulf. Twenty eight crude oil degrading bacteria were isolated from three mussels species collected from oil contaminated area at Persian Gulf. According to high growth and degradation of crude oil four strains were selected between 28 isolated strains for more study. Determination the nucleotide sequence of the gene encoding for 16S rRNA show that these isolated strains belong to: Shewanella algae isolate BHA1, Micrococcus luteus isolate BHA7, Pseudoalteromonas sp. isolate BHA8 and Shewanella haliotis isolate BHA35. The residual crude oil in culture medium was analysis by Gas Chromatography (GC). The results confirmed that these strains can degrade: 47.24%, 66.08%, 27.13% and 69.17% of crude oil respectively. These strains had high emulsification activity and biosurfactant production. Also, the effects of some factors on crude oil degradation by isolated strains were studied. The results show that the optimum concentration of crude oil was 2.5% and the best degradation take place at 12% of salinity. This research is the first reports on characterization of crude oil degrading bacteria from mussels at Persian Gulf and by using of these bacteria in the field the effect of oil pollution can be reduce on this marine environment. [ABSTRACT FROM AUTHOR]

Biosurfactants are surface active materials that are produced by some microorganisms. These molecules increase biodegradation of insoluble pollutants. In this study sediments and seawater samples were collected from the coastline of Bushehr provenance in the Persian Gulf and their biosurfactant producing bacteria were isolated. Biosurfactant producing bacteria were isolated by using an enrichment method in Bushnell-Hass medium with diesel oil as the sole carbon source. Five screening tests were used for selection of Biosurfactant producing bacteria: hemolysis in blood agar, oil spreading, drop collapse, emulsification activity and Bacterial Adhesion to Hydrocarbon test (BATH). These bacteria were identified using biochemical and molecular methods. Eighty different colonies were isolated from the collected samples. The most biosurfactant producing isolates related to petrochemical plants of Khark Island. Fourteen biosurfactant producing bacteria were selected between these isolates and 7 isolates were screened as these were predominant producers that belong to Shewanella alga , Shewanella upenei , Vibrio furnissii , Gallaecimonas pentaromativorans , Brevibacterium epidermidis , Psychrobacter namhaensis and Pseudomonas fluorescens . The largest clear zone diameters in oil spreading were observed for G. pentaromativorans strain O15. Also, this strain has the best emulsification activity and reduction of surface tension, suggesting it is the best of thee isolated strains. The results of this study confirmed that there is high diversity of biosurfactant producing bacteria in marine ecosystem of Iran and by application of these bacteria in petrochemical waste water environmental problems can be assisted. [ABSTRACT FROM AUTHOR]

Highlights: [•] Crude-oil degrading bacteria were isolated from Persian Gulf. [•] There is high diversity of crude-oil degrading bacteria in the Persian Gulf. [•] Corynebacterium variabile PG-Z is very useful for management of oil pollution in the sea. [ABSTRACT FROM AUTHOR]

Among six crude oil-degrading yeasts that were isolated from an oil-polluted area in the Persian Gulf, two yeast strains showed high degradation activity of aliphatic hydrocarbons. From an analysis of 18S rRNA sequences and biochemical characteristics, these strains were identified as Yarrowia lipolytica strains PG-20 and PG-32. Gas Chromatography (GC) analysis of the crude oil remaining in the culture medium after 1 week at 30 °C showed that the strains PG-20 and PG-32 degraded 68% and 58% of crude oil, respectively. The optimal growth condition and biodegradation of hydrocarbons was in ONR medium with an acidic pH (pH 5). These two strains may degrade aliphatic hydrocarbons more efficiently than aromatic hydrocarbons, although strain PG-20 had better degradation than strain PG-32. The two Y. lipolytica strains reduce surface tension when cultured on hydrocarbon substrates (1% v/v). These strains showed a cell surface hydrophobicity higher than 70%. These results suggested that Y. lipolytica strains PG-20 and PG-32 have high crude oil degrading activity due to their high emulsifying activity and cell hydrophobicity. In conclusion, these yeast strains can be useful for the bioremediation process in the Persian Gulf and decreasing oil pollution in this marine ecosystem. [ABSTRACT FROM AUTHOR]

Abstract: Twenty-five crude-oil-degrading bacteria were isolated from oil-contaminated sites in the Persian Gulf and the Caspian Sea. Based on a high growth rate on crude oil and on hydrocarbon degradation ability, 11 strains were selected from the 25 isolated strains for further study. Determination of the nucleotide sequence of the 16S rRNA gene showed that these isolated strains belonged to genera Acinetobacter, Pseudomonas, Gordonia, Rhodococcus, Cobetia, Halomonas, Alcanivorax, Marinobacter and Microbacterium. Among the 11 isolates, strains BS (Acinetobacter calcoaceticus, 98%) and PG-12 (Alcanivorax dieselolei, 98%) were the most effective in degrading crude oil. Rate of crude-oil degradation of 82% (isolate BS) and 71% (isolate PG-12) were observed after 1week of cultivation in mineral medium. These strains had high emulsification activity and biosurfactant production. GC–MS analysis showed that A. dieselolei PG-12 can degrade different alkanes in crude oil. Screening of the distribution of the alkane hydroxylase gene in 25 isolates in relation to the source of isolation indicated that the group (II) alkane hydroxylase is prevalent in the Caspian Sea, but in the Persian Gulf, the frequency of the group (III) alkane hydroxylase gene is greater than that of the group (II) alkane hydroxylase gene. [Copyright &y& Elsevier]

The responses of the natural microbial community in contaminated and uncontaminated sediments of the Persian Gulf and the Caspian Sea were evaluated by microcosm experiments. Analysis of bacterial densities (total heterotrophic, hydrocarbon-degrading and hydrocarbonoclastic bacteria count), microbial metabolic activities (enzymatic activities), and detection of catabolic genes of alkane hydroxylase systems by PCR were performed on subsurface sediment during 120 days of the experiment. The results showed that contaminated sediments from both areas had high dehydrogenase and lipase activities and low β-glucosidase activity. Lipase and dehydrogenase activities in Persian Gulf sediments were more than from Caspian Sea sediments. On the other hand, Caspian Sea sediments have lower dehydrogenase and lipase activity than the Persian Gulf. PCR analysis revealed the presence of alkane hydroxylase genes in both sediments with prevalence in contaminated sediments. Moreover, by PCR analysis with specific primers, the alkB1 gene of Alcanivorax sp. was detected only in contaminated seawater from the Persian Gulf as well as in artificially oil-contaminated seawater from the Persian Gulf and Caspian Sea. Apparently, the exposure to petroleum hydrocarbons contamination altered the microbial and enzymatic activities of sediments. The detection of alkB1 gene has been suggested as an indicator of oil contamination. [ABSTRACT FROM AUTHOR]

The Persian Gulf is a transit point for a lot of crude oil at the international level. The purpose of this research is to compare two methods of biostimulation and bioaugmentation for degradation of sediments contaminated with crude oil in the Persian Gulf. In this research, six types of microcosms were designed (Sediments from Khark Island). Some indicators such as: the quantity of marine bacteria, enzyme activity (Catalase, Polyphenol oxidase, Dehydrogenase), biodiversity indices and the percentage of crude oil degradation were analyzed during different days (0, 20, 40, 60, 80, 100 and 120). The results of this research showed that the highest quantity of heterotrophic and crude oil-degrading bacteria was found in the sixth microcosm (SB). This microcosm represents a combination of two methods: bioaugmentation and biostimulation (3.9 × 106 CFU g−1). Following crude oil pollution, the activity of catalase and polyphenol oxidase increased and the dehydrogenase enzyme decreased. The bioaugmentation microcosm exhibited the highest activity of enzymes among all the microcosms studied. Predominant bacteria in each microcosm belonged to: Cellulosimicrobium, Shewanella, Alcanivorax and Cobetia. The highest degradation of crude oil is related to the Stimulation-Bioaugmentation microcosm (SB). The statistical results of this research proved that there is a significant relationship between the type of method chosen for biodegradation with the sampling time and the quantity of marine bacteria. The results of this research confirm that crude oil pollution in the Persian Gulf sediments can be reduced by choosing the proper bioremediation method. • The effect of crude oil pollution on sediments of the Persian Gulf was studied • Stimulation of sediment in each microcosm by mineral elements cause increase in marine microbial population. • The Best microcosm for degradation of crude oil was integrated microcosm of bioaugmentation and biostimulation. [ABSTRACT FROM AUTHOR]