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Obecność biosurfaktantów pochodzenia mikrobiologicznego zmniejsza toksyczność chlorofenoli względem komórek Pseudomonas putida 2A. Micele powstałe z ramnolipidów wybiórczo zamykały chlorofenole i czyniły je mniej dostępnymi dla mikroorganizmów, co powodowało spadek toksyczności chlorofenoli względem komórek bakteryjnych. Zaobserwowano wzrost efektywnego stężenia ksenobiotyków powodującego 50-procentową inhibicję wzrostu mikroorganizmów (o 0,5, 0,35 oraz 0,15 mmol odpowiednio dla fenolu, 4-chlorofenolu i 2,4-dichlorofenolu). Zastosowanie surfaktantów jako środków chroniących mikroorganizmy otwiera nowe możliwości wykorzystania tego zjawiska w technikach bioremediacyjnych.
The yeast strain Candida maltosa EH 15 was used as a biological agent in the hydrocarbon and emulsified hydrocarbon biodegradation. Six different surface active compounds were used to emulsify hydrocarbons. Biodegradation degree and biomass quantity were determined daily over 7 days. The obtained results indicated the strong ability of Candida maltosa EH 15 for hydrocarbon biodegradation. The addition of the tested surfactants influenced hydrocarbon biodegradation; however, biodegradation effectiveness varies with the type and concentration of surfactant.
This study focused on assessing the phytoremediation potential of wetland plants toward atrazine in an aquatic environment. Changes in plant biomass and atrazine content were investigated for three plant species: sweet flag, broadleaf cattail, and narrow-leaf cattail. Atrazine removal and shifts in plant biomass were assessed. Two mathematical models were built to describe atrazine toxicity toward the studied plant species and fate of atrazine during long-term phytoremediation. Sweet flag exhibited the highest tolerance toward atrazine as well as the most efficient atrazine removal rate. The average atrazine half-life was significantly reduced from about 400 days to 5 days. The highest studied initial concentration of atrazine (20 mg/l) was reduced by more than 99% after 40 days.
Experiments focused on evaluating the ability of three aquatic plant species (sweet flag, common reed, and broadleaf cattail) to decontaminate industrial wastewater effluents from a nitroglycerin and nitroglycol production factory were carried out in the framework of this study. Toxicity of a nitrate-rich wastewater toward the studied plant species was determined by measurement of plant biomass gain, and subsequent mathematical modeling allowed for assessment of IC50 values. The studied plant species were cultivated in hydroponic cultures containing 1,500 mg/l of nitrates, 2.4 mg/l of nitroglycerin, and 1.0 mg/l of nitroglycol for 21 days, during which the decontamination efficiency of each nitrogen-based compound was analyzed. It was observed that the application of sweet flag and common reed contributed to a high nitrate removal efficiency (82 and 79%, accordingly). Sweet flag also was most efficient for decontamination of nitroglycerin (87%) and nitroglycol (42%), but the removal of the former compound was preferential.
The aim of our study was to investigate the effect of Triton X-100 on the biodegradation efficiency of hexadecane and phenanthrene carried out by two bacterial consortia. It was established that the tested consortia were not able to directly uptake compounds closed in micelles. It was observed that in micellar systems the nonionic synthetic surfactant was preferentially degraded (the degradation efficiency of Triton X-100 after 21 days was 70% of the initial concentration - 500 mg/l), followed by a lesser decomposition of hydrocarbon released from the micelles (30% for hexadecane and 20% for phenanthrene). However, when hydrocarbons were used as the sole carbon source, 70% of hexadecane and 30% of phenanthrene were degraded. The degradation of the surfactant did not contribute to notable shifts in bacterial community dynamics, as determined by Real-Time PCR. The obtained results suggest that if surfactant-supplementation is to be used as an integral part of a bioremediation process, then possible bioavailability decrease due to entrapment of the contaminant into surfactant micelles should also be taken into consideration, as this phenomenon may have a negative impact on the biodegradation efficiency. Surfactant-induced mobilization of otherwise recalcitrant hydrocarbons may contribute to the spreading of contaminants in the environment and prevent their biodegradation.
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