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1.
ACS Omega ; 9(11): 13112-13124, 2024 Mar 19.
Artículo en Inglés | MEDLINE | ID: mdl-38524448

RESUMEN

The utilization of coconut diethanolamide (p-CDEA) as a substitute polyol for petroleum-based polyol in fully biobased rigid polyurethane-urea foam (RPUAF) faces challenges due to its short chain and limited cross-linking capability. This leads to compromised cell wall resistance during foam expansion, resulting in significant ruptured cells and adverse effects on mechanical and thermal properties. To address this, a novel sequential amidation-prepolymerization route was employed on coconut oil, yielding a hydroxyl-terminated poly(urethane-urea) prepolymer polyol (COPUAP). Compared to p-CDEA, COPUAP exhibited a decreased hydroxyl value (496.3-473.2 mg KOH/g), an increase in amine value (13.464-24.561 mg KOH/g), and an increase in viscosity (472.4-755.8 mPa·s), indicating enhanced functionality of 34.3 mgKOH/g and chain lengthening. Further, COPUAP was utilized as the sole B-side polyol in the production of RPUAF (PU-COPUAP). The improved functionality of COPUAP and its improved cross-linking capability during foaming have significantly improved cell morphology, resulting in a remarkable 4.7-fold increase in compressive strength (132-628 kPa), a 3.5-fold increase in flexural strength (232-828 kPa), and improved insulation properties with a notable decrease in thermal conductivity (48.02-34.52 mW/m·K) compared to PU-CDEA in the literature. Additionally, PU-COPUAP exhibited a 16.5% increase in the water contact angle (114.93° to 133.87°), attributing to the formation of hydrophobic biuret segments and a tightly packed, highly cross-linked structure inhibiting water penetration. This innovative approach sets a new benchmark for fully biobased rigid foam production, delivering high load-bearing capacity, exceptional insulation, and significantly improved hydrophobicity.

2.
Environ Monit Assess ; 195(12): 1486, 2023 Nov 16.
Artículo en Inglés | MEDLINE | ID: mdl-37973642

RESUMEN

In recent years, many countries have relied on the massive use of personal protective equipment (PPE) following the recommendation of the World Health Organization (WHO) to combat COVID-19, an infectious disease caused by the SARS-CoV-2 virus. These PPEs include facemasks, face shields, disinfectant wipes, and disposable gloves. While PPE serves as protection, it can also be a source of pollution. This study is the first to establish a baseline monitoring and assessment of the spatial distribution of COVID-19-related PPE litter approaching the post-pandemic from the urban areas in Iligan City, Philippines. A total of 1632 COVID-19 PPE litter were gathered in all surveyed locations, predominantly facemasks (90.7%) and disinfectant wipes (8.8%). Among the surveyed areas, the location that recorded the highest count and density of PPE litter is in a residential zone (52.14%; n = 851; 0.0317 item m-2); the lowest was determined in recreational parks (2.57%; n = 42; 0.0016 item m-2). The significant difference in the total count of PPE items in each location could be traced to the varying land uses and ecosystems as well as the human behavior and activities. FTIR results reveal that all types of facemasks sampled are principally made of polypropylene, a material that threatens environmental sustainability and low recyclability. As the country is embracing the new normal and somewhat returning to pre-pandemic activities, this study calls for the prioritization of the government agendas on ecological solid waste management in the country.


Asunto(s)
COVID-19 , Desinfectantes , Humanos , Filipinas , Ecosistema , Monitoreo del Ambiente , COVID-19/epidemiología , COVID-19/prevención & control , Equipo de Protección Personal
3.
Mar Pollut Bull ; 194(Pt B): 115409, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37595450

RESUMEN

The Philippines is an archipelago that relies on marine resources. Butuan Bay in the Philippines supports aquaculture, which can contribute to and can be impacted by plastic pollution. However, the microplastics (MP) in milkfish, an important aquaculture species in the area, are yet to be ascertained. This study determined the prevalence of microplastics in the surrounding seawater and in the gut of adult milkfish from cages in Butuan and Nasipit in Butuan Bay. Water samples in Nasipit and Butuan contain 0.20 items/L and 1.00 items/L, respectively. MPs in milkfish in Butuan (10.27 items/individual) were significantly higher than in Nasipit (5.40 items/individual). A total of 235 MPs in 29 out of 30 fish samples (97 %) from the two sites were detected. The dominant MP shape and color were fiber and blue, respectively. The presence of microplastics in the milkfish may indicate a possible risk to the fish species and human health.


Asunto(s)
Microplásticos , Plásticos , Adulto , Animales , Humanos , Filipinas , Bahías , Acuicultura , Peces , Ingestión de Alimentos
4.
RSC Adv ; 13(30): 20941-20950, 2023 Jul 07.
Artículo en Inglés | MEDLINE | ID: mdl-37448637

RESUMEN

To attain efficient removal of hexavalent chromium (Cr6+) from aqueous solutions, a novel polyurethane foam-activated carbon (PUAC) adsorbent composite was developed. The composite material was synthesized by the binding of coconut shell-based activated carbon (AC) onto a coconut oil-based polyurethane matrix. To thoroughly characterize the physicochemical properties of the newly developed material, various analytical techniques including FTIR spectroscopy, SEM, XRD, BET, and TGA analyses were conducted. The removal efficiency of the PUAC composite in removing Cr6+ ions from aqueous solutions was evaluated through column experiments with the highest adsorption capacity of 28.41 mg g-1 while taking into account variables such as bed height, flow rate, initial Cr6+ ion concentration, and pH. Experimental data were fitted using Thomas, Yoon-Nelson, and Adams-Bohart models to predict the column profiles and the results demonstrate high breakthrough and exhaustion time dependence on these variables. Among the obtained R2 values of the models, a better fit was observed using the Thomas and Yoon-Nelson models, indicating their ability to effectively predict the adsorption of Cr6+ ions in a fixed bed column. Significantly, the exhausted adsorbent can be conveniently regenerated without any noteworthy loss of adsorption capability. Based on these findings, it can be concluded that this new PUAC composite material holds significant promise as a potent sorbent for wastewater treatment backed by its excellent performance, cost-effectiveness, biodegradability, and outstanding reusability.

5.
Artículo en Inglés | MEDLINE | ID: mdl-37372718

RESUMEN

Rivers are vital water sources for humans and homes for aquatic organisms. Conversely, they are well known as the route of plastics into the ocean. Despite being the world's number one emitter of riverine plastics into the ocean, microplastics (MPs), or plastic particles less than 5 mm, in the Philippines' rivers are relatively unexplored. Water samples were collected from six sampling stations along the river channel of the Cagayan de Oro River, one of the largest rivers in Northern Mindanao, Philippines. The extracted microplastics' abundance, distribution, and characteristics were analyzed using a stereomicroscope and Fourier transform infrared spectroscopy (FTIR). The results showed a mean concentration of 300 items/m3 of MPs dominated by blue-colored (59%), fiber (63%), 0.3-0.5 mm (44%), and polyacetylene (48%) particles. The highest concentration of microplastics was recorded near the mouth of the river, and the lowest was in the middle area. The findings indicated a significant difference in MP concentration at the sampling stations. This study is the first assessment of microplastic in a river in Mindanao. The results of this study will aid in formulating mitigation strategies for reducing riverine plastic emissions.


Asunto(s)
Microplásticos , Contaminantes Químicos del Agua , Humanos , Plásticos , Ríos , Filipinas , Contaminantes Químicos del Agua/análisis , Monitoreo del Ambiente , Agua
6.
Artículo en Inglés | MEDLINE | ID: mdl-37122120

RESUMEN

Polycyclic aromatic hydrocarbons (PAHs) are among the most widely spread pollutants in the environment including the agricultural soil. PAH degradation by indigenous bacteria is an effective and economical means to remove these pollutants from the environment. Here, we report a bacterial consortium (Pdy-1) isolated from paddy rice soil in northern Japan able to degrade polycyclic aromatic hydrocarbons (PAHs) at high rates. Pdy-1 was incubated with a mixture of PAH compounds (fluorene, phenanthrene, and pyrene) in Bushnell Haas Medium at a final concentration of 100 mg/L each. PDY-1 degraded 100% of fluorene, 95% of phenanthrene, and 52% of pyrene in 5 days. Phenanthrene and pyrene were completely degraded at 10 d and 15 d, respectively. Cloning of the 16S rRNA gene revealed that the consortium was composed of 40% Achromobacter and 7% each of Castelaniella, Rhodanobacter, and Hypomicrobium. Comamonas, Ferrovibrio, Terrimonas, Bordetella, Rhizobium, and Pseudonocardia were also detected. PCR-DGGE showed the dynamics of the consortium during the incubation period. Real-time PCR revealed that PAH degrading genes such as the gram-positive ring dihydroxylating genes (PAH-RDH) and pyrene dioxygenase (nidA) were most abundant at day 5 when the rapid biodegradation of the PAHs was observed. This study improves our understanding on dynamics and characteristics of an effective PAH-degrading bacterial consortium from paddy rice soil.


Asunto(s)
Contaminantes Ambientales , Oryza , Fenantrenos , Hidrocarburos Policíclicos Aromáticos , Contaminantes del Suelo , Hidrocarburos Policíclicos Aromáticos/metabolismo , Oryza/metabolismo , Suelo , Consorcios Microbianos , ARN Ribosómico 16S/genética , Contaminantes del Suelo/metabolismo , Fenantrenos/metabolismo , Fluorenos/metabolismo , Pirenos/metabolismo , Bacterias/metabolismo , Biodegradación Ambiental , Contaminantes Ambientales/metabolismo , Microbiología del Suelo
7.
Environ Sci Pollut Res Int ; 30(18): 53662-53673, 2023 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-36859643

RESUMEN

Microplastics (< 5 mm) have lately been identified in the atmosphere of urban, suburban, and even distant places far from plastic particle areas, suggesting the possibility of long-distance atmospheric transport of microplastics. However, the occurrence, fate, transmission, and effects of these suspended atmospheric microplastics (SAMPs) are all currently unknown in the Philippines. This study investigated the presence of suspected microplastic in the atmosphere of sixteen cities and one municipality of Metro Manila, Philippines. Sampling was conducted using a respirable dust sampler mounted with a Whatman GF/C filter paper at an intake flow rate of 1.4 L/min with Whatman GF/C filter paper. Results reveal that all seventeen sampling areas have the presence of SAMPs. A total of 155 SAMPs were found and confirmed in Metro Manila, with the highest concentration in Muntinlupa City and Mandaluyong City (0.023 SAMP/NCM). Fourteen SAMP types were identified across the sampling areas, ⁓ 74% with polyester. This study is the first record of the presence of microplastics suspended in the ambient air in the Philippines. It is estimated that an adult person in Metro Manila has the potential to inhale (5-8 per minute, normal minute ventilation) about 1 SAMP if exposed for about 99.0 to 132 h. Further studies should be done to evaluate the fate and health effects of these SAMPs in Metro Manila's setting.


Asunto(s)
Plásticos , Contaminantes Químicos del Agua , Adulto , Humanos , Microplásticos , Filipinas/epidemiología , Compuestos de Fenilmercurio , Monitoreo del Ambiente , Contaminantes Químicos del Agua/análisis
8.
Mar Pollut Bull ; 188: 114681, 2023 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-36758311

RESUMEN

Facemasks were widely used as a protection against SARS-COV-2, which significantly reduced COVID-19 transmission during the pandemic. However, concerns have been raised regarding its adverse impacts on human health due to intense use and mismanagement. Although rampant plastic littering was the norm before the pandemic, the magnitude of the problem is worsening as potentially COVID-19-infected facemasks are thrown along the shoreline. This study assessed the discarded facemasks on the most popular beach destinations in Mati City, Davao Oriental, Philippines. A total of N = 284 discarded facemasks were found in a cumulative area of 22,500 m2, with an average density of 8.4 × 10-4 items/m2. The surgical facemask (82 %; n = 234) was the most abundant type of facemask found in the areas, followed by KF94 (16 %; n = 45) and KN95 (2 %; n = 5). The Analysis of Variance (ANOVA) showed significant differences in the visual counts of facemasks on the three beaches (p < 0.05).


Asunto(s)
COVID-19 , Máscaras , Humanos , COVID-19/prevención & control , SARS-CoV-2 , Filipinas , Equipo de Protección Personal
9.
Environ Sci Pollut Res Int ; 30(11): 29824-29833, 2023 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-36418829

RESUMEN

The pollution of aquatic systems by microplastics is a well-known environmental problem. However, limited studies have been conducted in freshwater systems, especially in the Philippines. Here, we determined for the first time the amount of microplastics in the Philippines' largest freshwater lake, the Laguna de Bay. Ten (10) sampling stations on the lake's surface water were sampled using a plankton net. Samples were extracted and analyzed using Fourier-transform infrared spectroscopy (FTIR). A total of 100 microplastics were identified from 10 sites with a mean density of 14.29 items/m3. Most microplastics were fibers (57%), while blue-colored microplastics predominated in the sampling areas (53%). There were 11 microplastic polymers identified, predominantly polypropylene (PP), ethylene vinyl acetate copolymer (EVA), and polyethylene terephthalate (PET), which together account for 65% of the total microplastics in the areas. The results show that there is a higher microplastic density in areas with high relative population density, which necessitates implementing proper plastic waste management measures in the communities operating on the lake and in its vicinity to protect the lake's ecosystem services. Furthermore, future research should also focus on the environmental risks posed by these microplastics, especially on the fisheries and aquatic resources.


Asunto(s)
Microplásticos , Contaminantes Químicos del Agua , Plásticos , Lagos/química , Agua , Bahías , Ecosistema , Filipinas , Monitoreo del Ambiente/métodos , Contaminantes Químicos del Agua/análisis
10.
Mar Pollut Bull ; 185(Pt A): 114233, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36252442

RESUMEN

Despite being a leading pollutant in the ocean, there are limited studies about plastic litter in seagrasses, and none has been documented in the Philippines. This study determined the abundance and composition of macroplastics in seagrass beds of Iligan City, Philippines. Plastics were collected from transect lines laid in seagrass beds of four sites (Dalipuga, Hinaplanon, Tominobo and Buru-un), and three locations (landward, midward, seaward) in each site, periodically within 42 days. A total of 921 macroplastic items were collected in all sampling sites, of which 308 were from Buru-un, 271 from Tominobo, 240 from Dalipuga, and 102 from Hinaplanon. Landward areas have a significantly higher density than either midward or seaward. The first sampling was higher than the succeeding sampling period. Food packaging, plastic bags, and fragments predominated the litter in seagrass. This study is the first to document the presence of macroplastics in seagrass beds in the Philippines.


Asunto(s)
Plásticos , Residuos , Residuos/análisis , Filipinas , Contaminación Ambiental , Monitoreo del Ambiente
11.
Mar Pollut Bull ; 182: 113934, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35870359

RESUMEN

The emergence of the COVID-19 pandemic has caused worldwide health constraints. This study was conducted to establish a baseline monitoring survey to describe the distribution of PPE litters during the COVID-19 pandemic in the province of Palawan, Philippines. A total of 386 COVID-19-related PPE items were present in 83 % of coastal sampling sites with over a cumulative area of 48,200 m2, with a density of 8 × 10-3 items m-2. The facemask (98 %; n = 377) was the primary type of PPE, followed by face shield (2 %; n = 9). Meanwhile, the daily density of PPE litters in San Manuel, Puerto Princesa ranged from 0 to 9.9 × 10-2 items m-2, with a mean density of 8 × 10-3 items m-2. The accumulation rates of PPE items ranged from 3.27 × 10-1 items to 1.143 items d-1, with an average rate of 7.29 × 10-1 items d-1.


Asunto(s)
COVID-19 , Equipo de Protección Personal , Humanos , Pandemias , Filipinas , SARS-CoV-2
12.
Front Psychol ; 12: 661810, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34447327

RESUMEN

Despite the potentially huge contributions that coastal communities might make in marine resource management and sustainability, their participation in such efforts have only been recognized recently, particularly in Southeast Asia. Involving community perceptions can offer new insights for policy makers and resource managers and can elicit strong commitment and support from the communities themselves. This article aims to understand the perceptions of coastal communities of local environmental issues, specifically how these have developed over time, to understand the expectations and perceptions of trends. Sixteen marine environmental issues were identified during stakeholder meetings in Palawan, Philippines. A co-developed survey was administered to 431 respondents from coastal communities in two municipalities (Taytay and Aborlan) and in the city of Puerto Princesa in Palawan. The results show variation in the perceptions and expectations across issues. We find that communities expect positive trends for mangrove coverage, beach tree cover, and seagrass coverage as well as for seaweed farming and quality of drinking water. The amount of plastic litter, wild fish and shellfish, and the severity of sewage pollution are perceived to get slightly worse. The aquaculture sector is expected to remain unchanged in the future as it had been in the past. We also find significant differences in how people from different areas of residence perceive their marine environment. In the discussion, we mapped these different community perceptions on existing policies and their implementation. We further recommend how community perceptions can be integrated into resource management and policy making in the future.

13.
World J Microbiol Biotechnol ; 37(7): 122, 2021 Jun 21.
Artículo en Inglés | MEDLINE | ID: mdl-34151386

RESUMEN

The contamination of the environment by crude oil and its by-products, mainly composed of aliphatic and aromatic hydrocarbons, is a widespread problem. Biodegradation by bacteria is one of the processes responsible for the removal of these pollutants. This study was conducted to determine the abilities of Burkholderia sp. B5, Cupriavidus sp. B1, Pseudomonas sp. T1, and another Cupriavidus sp. X5 to degrade binary mixtures of octane (representing aliphatic hydrocarbons) with benzene, toluene, ethylbenzene, or xylene (BTEX as aromatic hydrocarbons) at a final concentration of 100 ppm under aerobic conditions. These strains were isolated from an enriched bacterial consortium (Yabase or Y consortium) that prefer to degrade aromatic hydrocarbon over aliphatic hydrocarbons. We found that B5 degraded all BTEX compounds more rapidly than octane. In contrast, B1, T1 and X5 utilized more of octane over BTX compounds. B5 also preferred to use benzene over octane with varying concentrations of up to 200 mg/l. B5 possesses alkane hydroxylase (alkB) and catechol 2,3-dioxygenase (C23D) genes, which are responsible for the degradation of alkanes and aromatic hydrocarbons, respectively. This study strongly supports our notion that Burkholderia played a key role in the preferential degradation of aromatic hydrocarbons over aliphatic hydrocarbons in the previously characterized Y consortium. The preferential degradation of more toxic aromatic hydrocarbons over aliphatics is crucial in risk-based bioremediation.


Asunto(s)
Burkholderia/metabolismo , Cupriavidus/metabolismo , Hidrocarburos Aromáticos/metabolismo , Octanos/metabolismo , Pseudomonas/metabolismo , Técnicas de Tipificación Bacteriana , Benceno/metabolismo , Derivados del Benceno/metabolismo , Biodegradación Ambiental , Burkholderia/clasificación , Burkholderia/genética , Catecol 2,3-Dioxigenasa/genética , Cupriavidus/clasificación , Cupriavidus/genética , Citocromo P-450 CYP4A/genética , ADN Bacteriano , Microbiología Ambiental , Contaminantes Ambientales/metabolismo , Yacimiento de Petróleo y Gas/microbiología , Petróleo/microbiología , Pseudomonas/clasificación , Pseudomonas/genética , ARN Ribosómico 16S , Tolueno/metabolismo , Xilenos/metabolismo
14.
Mar Pollut Bull ; 169: 112520, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-34058497

RESUMEN

Marine plastic litter pollution has become an emerging threat to the Philippines, especially in Palawan. This study was conducted to investigate the macroplastic litter and determine the clean-coast index (CCI) of the residential and non-residential sites on the coasts of Puerto Princesa, Palawan. Plastic litters were sampled from 21 coastal barangays by delineating a 50-m-long transect line with three 4 m × 4 m quadrats. The litter sampled were counted and sorted into categories. The results showed that 17 sites were contaminated with plastic litters. In terms of residential and non-residential sites, the east coast has thrice as much plastic, 2.61 items/m2 and 1.26 items/m2 compared to west coast with only 1.57 items/m2 and 0.14 items/m2, respectively. The plastics sampled were predominantly fishing line (nylon), food packaging, and fragments. The calculated CCI revealed that 76% of the sites sampled were categorized as dirty and extremely dirty.


Asunto(s)
Playas , Plásticos , Monitoreo del Ambiente , Filipinas , Residuos/análisis
15.
Mar Pollut Bull ; 162: 111867, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33276157

RESUMEN

During oil spills in the field or for laboratory incubation studies, different oil concentrations are often encountered or applied, yet how initial oil concentration affects biodegradation rates of hydrocarbons and the development of oil degraders remains unclear. We incubated seawater for 50 d with different oil concentrations (0, 50, 100, 200, 400 and 800 ppm). n-Alkanes and polycyclic aromatic hydrocarbons (PAHs), and the bacterial community were analyzed periodically. Results show that the biodegradation rates of alkanes, derived from first order kinetics, decreased with increasing oil concentration, but percent residual was ~50% regardless of the initial concentration. In contrast, the biodegradation rates of PAHs increased with concentration, and the percent residual increased with oil concentration. Increasing oil concentration resulted in increased abundances of Rhodobacterales, Altererythrobacter, and Neptuniibacter. However, Alcanivorax abundance was barely detected in 400 and 800 ppm. Overall, oil concentration critically affected the degradation of hydrocarbons and the bacterial community.


Asunto(s)
Contaminación por Petróleo , Petróleo , Biodegradación Ambiental , Hidrocarburos , ARN Ribosómico 16S , Agua de Mar
16.
Environ Sci Pollut Res Int ; 27(28): 34987-34999, 2020 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-32588304

RESUMEN

Hurricane Harvey was the wettest hurricane in US history bringing record rainfall and widespread flooding in Houston, TX. The resulting storm- and floodwaters largely emptied into the Galveston Bay. Surface water was collected from 10 stations during five cruises to investigate the concentrations and sources of 16 priority polycyclic aromatic hydrocarbons (PAHs), and relative abundances of PAH-degrading bacteria. Highest PAH levels (102-167 ng/L) were detected during the first sampling event, decreasing to 36-69 ng/L within a week. Four sites had elevated concentrations of carcinogenic benzo[a]pyrene that exceeded the Texas Standard for Surface Water threshold. The highest relative abundances of known PAH-degrading bacteria Burkholderiaceae, Comamonadaceae, and Sphingomonadales were detected during the first and second sampling events. PAH origins were about 60% pyrogenic, 2% petrogenic, and the remainder of mixed sources. This study improves our understanding on the fate, source, and distributions of PAHs in Galveston Bay after an extreme flooding event.


Asunto(s)
Tormentas Ciclónicas , Hidrocarburos Policíclicos Aromáticos/análisis , Contaminantes Químicos del Agua/análisis , Bacterias , Bahías , Monitoreo del Ambiente , Sedimentos Geológicos , Texas
17.
Harmful Algae ; 95: 101802, 2020 05.
Artículo en Inglés | MEDLINE | ID: mdl-32439059

RESUMEN

The association between phytoplankton blooms and oil spills is still controversial despite numerous studies. Surprisingly, to date, there have been no studies on the effect of bacterial communities (BCs) exposed to crude oil on phytoplankton growth, even though crude oil changes BCs, which can then affect phytoplankton growth and species composition. Co-culture with crude oil-exposed BCs significantly stimulated the growth of Prorocentrum texanum in the laboratory. To gain more direct evidence, oil-degrading bacteria from oil-contaminated sediment collected after the Texas City "Y" oil spill were isolated, and changes in dinoflagellate growth when co-cultured with single bacterial isolates was investigated. The oil-degrading bacterial isolates significantly stimulated the growth of dinoflagellates (axenic and xenic cultures) through releasing growth-promoting substances. This study provides new evidence for the potential role of oil-degrading bacteria in the formation of phytoplankton blooms after an oil spill.


Asunto(s)
Dinoflagelados , Contaminación por Petróleo , Petróleo , Bacterias , Fitoplancton
18.
Chemosphere ; 234: 789-795, 2019 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-31247488

RESUMEN

Grasses are advantageous in the removal of polycyclic aromatic hydrocarbons (PAHs) in soil because of their fibrous root, high tolerance to environmental stress, and low nutritional requirements. In this study, a pot experiment was conducted to test the ability of four grasses to remove PAHs in the soil, and to investigate the corresponding bacterial community shift in the rhizosphere of each. Sudangrass achieved the maximum removal of PAHs at 98% dissipation rate after 20 days. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and next-generation sequencing revealed that sudangrass specially enriched the growth of a known PAHs degrader, Sphingomonadales, regardless of the presence or absence of PAHs in the soil. Moreover, the gene copy numbers of PAHs catabolic genes, PAH-RHDα and nidA, as measured by real time-PCR (RT-PCR) were highest in the soil planted with sudangrass. Overall, this study suggested that sudangrass further enhanced the dissipation of PAHs by enriching Sphingomonadales in its rhizosphere.


Asunto(s)
Biodegradación Ambiental , Hidrocarburos Policíclicos Aromáticos/metabolismo , Rizosfera , Sorghum/microbiología , Bacterias/aislamiento & purificación , Bacterias/metabolismo , Poaceae/metabolismo , Hidrocarburos Policíclicos Aromáticos/análisis , Contaminantes del Suelo/análisis , Contaminantes del Suelo/metabolismo , Sphingomonadaceae/crecimiento & desarrollo , Sphingomonadaceae/metabolismo
19.
PLoS One ; 13(12): e0208406, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30521589

RESUMEN

Sinking marine oil snow was found to be a major mechanism in the transport of spilled oil from the surface to the deep sea following the Deepwater Horizon (DwH) oil spill. Marine snow formation is primarily facilitated by extracellular polymeric substances (EPS), which are mainly composed of proteins and carbohydrates secreted by microorganisms. While numerous bacteria have been identified to degrade oil, there is a paucity of knowledge on bacteria that produce EPS in response to oil and Corexit exposure in the northern Gulf of Mexico (nGoM). In this study, we isolated bacteria from surface water of the nGoM that grow on oil or Corexit dispersant. Among the 100 strains isolated, nine were identified to produce remarkable amounts of EPS. 16S rRNA gene analysis revealed that six isolates (strains C1, C5, W10, W11, W14, W20) belong to the genus Alteromonas; the others were related to Thalassospira (C8), Aestuariibacter (C12), and Escherichia (W13a). The isolates preferably degraded alkanes (17-77%), over polycyclic aromatic hydrocarbons (0.90-23%). The EPS production was determined in the presence of a water accommodated fraction (WAF) of oil, a chemical enhanced WAF (CEWAF), Corexit, and control. The highest production of visible aggregates was found in Corexit followed by CEWAF, WAF, and control; indicating that Corexit generally enhanced EPS production. The addition of WAF and Corexit did not affect the carbohydrate content, but significantly increased the protein content of the EPS. On the average, WAF and CEWAF treatments had nine to ten times more proteins, and Corexit had five times higher than the control. Our results reveal that Alteromonas and Thalassospira, among the commonly reported bacteria following the DwH spill, produce protein rich EPS that could have crucial roles in oil degradation and marine snow formation. This study highlights the link between EPS production and bacterial oil-degrading capacity that should not be overlooked during spilled oil clearance.


Asunto(s)
Bacterias/clasificación , Matriz Extracelular de Sustancias Poliméricas/microbiología , Sedimentos Geológicos/microbiología , Contaminación por Petróleo/análisis , Alteromonas/clasificación , Alteromonas/aislamiento & purificación , Bacterias/aislamiento & purificación , Bacterias/metabolismo , Biodegradación Ambiental , Carbohidratos/análisis , ADN Bacteriano/genética , ADN Ribosómico/genética , Matriz Extracelular de Sustancias Poliméricas/metabolismo , Golfo de México , Filogenia , ARN Ribosómico 16S/genética , Rhodospirillaceae/clasificación , Rhodospirillaceae/aislamiento & purificación
20.
ISME J ; 12(10): 2532-2543, 2018 10.
Artículo en Inglés | MEDLINE | ID: mdl-29950702

RESUMEN

The Deepwater Horizon (DWH) blowout resulted in the deposition to the seafloor of up to 4.9% of 200 million gallons of oil released into the Gulf of Mexico. The petroleum hydrocarbon concentrations near the wellhead were high immediately after the spill, but returned to background levels a few years after the spill. Microbial communities in the seafloor are thought to be responsible for the degradation of hydrocarbons, however, our knowledge is primarily based upon gene diversity surveys and hydrocarbon concentration in field sediment samples. Here, we investigated the oil degradation potential and changes in bacterial community by amending seafloor sediment collected near the DWH site with crude oil and both oil and Corexit dispersant. Polycyclic aromatic hydrocarbons were rapidly degraded during the first 30 days of incubation, while alkanes were degraded more slowly. With the degradation of hydrocarbons, the relative abundances of Colwelliaceae, Alteromonadaceae, Methylococales, Alcanivorax, Bacteriovorax, and Phaeobacter increased remarkably. However, the abundances of oil-degrading bacteria changed with oil chemistry. Colwelliaceae decreased with increasing oil degradation, whereas Alcanivorax and Methylococcales increased considerably. We assembled seven genomes from the metagenome, including ones belonging to Colwellia, Alteromonadaceae, Rhodobacteraceae, the newly reported genus Woeseia, and candidate phylum NC10, all of which possess a repertoire of genes for hydrocarbon degradation. Moreover, genes related to hydrocarbon degradation were highly enriched in the oiled treatment, suggesting that the hydrocarbons were biodegraded, and that the indigenous microflora have a remarkable potential for the natural attenuation of spilled oil in the deep-sea surface sediment.


Asunto(s)
Biodegradación Ambiental , Sedimentos Geológicos/microbiología , Contaminación por Petróleo/análisis , Petróleo/metabolismo , Proteobacteria/clasificación , Contaminantes Químicos del Agua/metabolismo , Golfo de México , Louisiana , Proteobacteria/metabolismo , Contaminantes Químicos del Agua/análisis
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