peptones and phenanthrene

Mangrove ecosystems play curial roles in providing many ecological services and alleviating global climate change. However, they are in decline globally, mainly threatened by human activities and global warming, and organic pollutants, especially PAHs, are among the crucial reasons. Microbial remediation is a cost-effective and environmentally friendly way of alleviating PAH contamination. Therefore, understanding the effects of environmental and nutritional parameters on the biodegradation of polycyclic aromatic hydrocarbons (PAHs) is significant for the bioremediation of PAH contamination. In the present study, five bacterial strains, designated as Bp1 (Genus

Topics: Bacteria; Biodegradation, Environmental; Ecosystem; Fertilizers; Humans; Metals, Heavy; Naphthalenes; Peptones; Phenanthrenes; Polycyclic Aromatic Hydrocarbons; Pyrenes

Sorption and desorption of phenanthrene (PHE) onto black carbon (BC) extracted from sediments were studied in the presence of three types of dissolved organic matter (DOM), including L-phenylalanine (L-PH), peptone and citric acid. The nonlinearity of the sorption isotherms increased in the presence of DOM. The presence of L-PH reduced the sorption capacity and desorption hysteresis because of the solubilization of PHE in L-PH solution. Peptone at 50-500 mg/L also led to a decrease in sorption attributed to solubilization, although the sorbed peptone on the BC surface could slightly increase PHE sorption. Unlike L-PH and peptone, citric acid enhanced the sorption capacity and irreversibility of PHE on BC mainly due to the strong sorption of citric acid on the BC surface. Our results may help to understand the different impacts of DOM on the distribution and transport of PAH in the environment.

Topics: Adsorption; Carbon; Citric Acid; Peptones; Phenanthrenes; Phenylalanine; Soil Pollutants

Increasing production and use of single-walled carbon nanotubes (SWCNT) will inevitably lead to release of these nanoparticles to aquatic ecosystems. Similar to black carbon (BC) particles, SWCNT have a high affinity for hydrophobic organic contaminants (HOCs) and therefore the presence of SWCNT in sediment may lead to altered bioavailability of HOCs. We compared SWCNT with biochar and charcoal on their effect on the microbial degradability of 0.05 mg kg(-1) (14)C-phenanthrene (PHE) by Mycobacterium vanbaalenii PYR-1 in two sediments with different organic carbon (OC) contents. When the amendment rate of SWCNT or BC was 1 mg g(-1), PHE mineralization was inhibited much more significantly by SWCNT than by either biochar or charcoal. After 360 h of incubation, the mineralized fraction of PHE in the presence of SWCNT was 59.5% of the non-amended control in the sediment with low OC content, and only 42.4% in the other sediment with a higher OC content. Analysis of the freely dissolved concentration (C (free)) using disposable polydimethylsiloxane (PDMS) fibers showed that SWCNT decreased C (free) by 85-95%, apparently due to preferential sorption of PHE to SWCNT particles that had a much larger specific surface area and pore volume than biochar or charcoal. However, pre-interaction of SWCNT with dissolved organic matter (peptone, tannic acid, and humic acid) led to attachment of polar functional groups and reduced surface area on SWCNT, resulting in decreased PHE sorption and an alleviated effect on PHE biodegradation in the order of peptone > tannic acid > humic acid.

Topics: Adsorption; Charcoal; Environmental Restoration and Remediation; Geologic Sediments; Humic Substances; Nanotubes, Carbon; Peptones; Phenanthrenes; Tannins; Water Microbiology; Water Pollutants, Chemical

Sorption of three types of dissolved organic matter (DOM; i.e., humic acid, peptone and alpha-phenylalanine) by a mutiwalled carbon nanotube (MWNT40) and sorption of phenanthrene (Phen), naphthalene (Naph), and 1-naphthol (1-Naph) by the original and DOM-coated MWNT40 were examined. Sorption data of Phen, Naph, and 1-Naph by all sorbents were fitted with Freundlich and Polanyi models. MWNT40 had nonlinear isotherms for all DOMs examined. Sorption of DOMs by MWNT40 followed the order peptone > humic acid > alpha-phenylalanine. The humic acid used in this study had much lower sorption for Phen, Naph, and 1-Naph than MWNT40, but its coating did not make striking changes on sorption of these compounds by MWNT40, suggesting that humic acid coating dramatically altered the physical form and surface properties of MWNT40. Peptone coating made the strongest suppression on sorption of Phen, Naph, and 1-Naph by MWNT40 among the three DOMs used, due to its highest sorption on MWNT40, thus causing a great reduction in accessibility of sorption sites. Polanyi modeling results showed that reduction in the maximum volume sorption capacity (Q0) of MWNT40 induced by DOM coating followed the order Phen < Naph < 1-Naph. 1-Naph was less hydrophobic than Phen and Naph but it had much higher sorbed volume (V(m)) than Phen and Naph at individual RT In(S(w)/C(e))/V(s)points for all sorbents. The correlation curve for the Polanyi model was applicable for sorption of aromatic compounds of similar structure by the original and DOM-coated carbon nanotubes.

Topics: Adsorption; Carbon; Environmental Monitoring; Humic Substances; Kinetics; Models, Chemical; Nanotechnology; Nanotubes, Carbon; Organic Chemicals; Peptones; Phenanthrenes; Phenylalanine; Soil Pollutants