Possible enhancement of biodegradation of petroleum hydrocarbons in agricultural soil after tank truck accident (~5000 mg/kg dry soil initial concentration) by bioaugmentation of diesel degrading Pseudomonas fluorescens strain and addition of abiotic additives (humates, zeolite) was studied in a 9-month pot experiment. The biodegradation process was followed by means of analytical parameters (hydrocarbon index expressed as content of C10-C40 aliphatic hydrocarbons, ratio pristane/C17, and total organic carbon content) and characterization of soil microbial community (content of phospholipid fatty acids (PLFA) as an indicator of living microbial biomass, respiration, and dehydrogenase activity). The concentration of petroleum hydrocarbons (C10-C40) was successfully reduced by ~60% in all 15 experiment variants. The bioaugmentation resulted in faster hydrocarbon elimination. On the contrary, the addition of humates and zeolite caused only a negligible increase in the degradation rate. These factors, however, affected significantly the amount of PLFA. The humates caused significantly faster increase of the total PLFA suggesting improvement of the soil microenvironment. Zeolite caused significantly slower increase of the total PLFA; nevertheless it aided in homogenization of the soil. Comparison of microbial activities and total PLFA revealed that only a small fraction of autochthonous microbes took part in the biodegradation which confirms that bioaugmentation was the most important treatment.
- MeSH
- benzin * MeSH
- biodegradace * MeSH
- kinetika MeSH
- lidé MeSH
- půda * MeSH
- půdní mikrobiologie MeSH
- zemědělství * MeSH
- zeolity chemie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The content of phospholipid fatty acids (PLFA) was determined in samples of polyvinyl alcohol lenses (Lentikats Biocatalyst, LB) with encapsulated Paracoccus denitrificans withdrawn during long-term denitrification experiments. The total PLFA content correlated highly with specific denitrification activities of LB as well as biomass estimation based on image analyses of microscopic photos. The results confirmed the applicability of PLFA determination for estimation of the amount of living encapsulated microbial biomass during biotechnological applications.
Reliable analysis of anions in mine waters with high iron and sulfate contents is important for their characterization. However, both traditional and LC methods failed in direct anion analysis. The article describes two sample pretreatments – alkalization and cation exchange. The pretreated water samples were analyzed by potentiometric titration, spectrophotometry, ion chromatography with conductivity detector in suppressed regime and HPLC with diode array detector using indirect UV detection at 260 nm. Both the sample pretreatments enable determination of some anions, the former procedure being more suitable for the purpose. Potentiometric titration and spectrophotometry seem to be the most suitable due to low detection limits for all the selected anions ranging from 0.4 to 1.8 mg l–1. The application of ion chromatography and liquid chromatography with diode array detector for the purpose is also possible. However, due to very high detection limits of samples pretreated by cation exchange (26–121 mg l–1) and low recoveries of samples pretreated by alkalization (<17 %) for all the selected anions, HPLC-DAD is not suitable for analysis of real samples. Validation and analytical characteristics of the methods are given and discussed.
The bioluminescence (BLM) and colony-forming units (CFU) of Pseudomonas fluorescens HK44 were monitored during encapsulation into pre-polymerized Si(OMe)₄. The non-induced BLM of free cells was increased in the presence of 0.5-2.5 % MeOH. After mixing silica sol with the cell suspension, both BLM and CFU dropped to 1-3 and 8-18 %, respectively; both remained lowered as long as the silica biofilm contained residual MeOH. The kinetics of MeOH being released from silica biofilms (a thickness of 2-6 mm) were first-order. The decrease of bacterial activity due to encapsulation was proportional to the biofilm thickness. MeOH evolving during encapsulation is probably the principal stress factor but not the only one.
To fulfil the requirements of health regulations and water quality, it is necessary to monitor the concentrations of volatile hydrocarbons in water at rather low levels. A simple and rapid GC-FID method utilizing liquid-liquid microextraction with xylene in closed vials for the determination of ten selected volatile chlorinated hydrocarbons in water before and after remediation was developed. The procedure allowed to determine selected hydrocarbons at concentrations 10?20 µg l-1 using 1000-ml samples or 30?50 µg l-1 using 60-ml samples. A significant decrease in the detection limits to 2?20 µg l-1 (for 60-ml samples) was achieved by lowering the noise level after replacing GC gases by higher-purity gases and using 1-chloropropane as internal standard. The determination of CHCl3 and CCl4 at the µg l-1 levels was feasible using an ECD detector. Even lower detection limits can be achieved by modification of the GC injector and by injecting a large volume of the xylene extract.
