Franz Schinner

On-Line Monitoring of Microbial Volatile Metabolites by Proton Transfer Reaction-Mass Spectrometry

ABSTRACT A method for analysis of volatile organic compounds (VOCs) from microbial cultures was established using proton transfer reaction-mass spectrometry (PTR-MS). A newly developed sampling system was coupled to a PTR-MS instrument to allow on-line monitoring of VOCs in the dynamic headspaces of microbial cultures. The novel PTR-MS method was evaluated for four reference organisms: Escherichia coli, Shigella flexneri, Salmonella enterica, and Candida tropicalis. Headspace VOCs in sampling bottles containing actively growing cultures and uninoculated culture medium controls were sequentially analyzed by PTR-MS. Characteristic marker ions were found for certain microbial cultures: C. tropicalis could be identified by several unique markers compared with the other three organisms, and E. coli and S. enterica were distinguishable from each other and from S. flexneri by specific marker ions, demonstrating the potential of this method to differentiate between even closely related microorganisms. Although the temporal profiles of some VOCs were similar to the growth dynamics of the microbial cultures, most VOCs showed a different temporal profile, characterized by constant or decreasing VOC levels or by single or multiple peaks over 24 h of incubation. These findings strongly indicate that the temporal evolution of VOC emissions during growth must be considered if characterization or differentiation based on microbial VOC emissions is attempted. Our study may help to establish the analysis of VOCs by on-line PTR-MS as a routine method in microbiology and as a tool for monitoring environmental and biotechnological processes.

Methods in soil biology.

Methods in soil biology , Methods in soil biology , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی

Potential of halotolerant and halophilic microorganisms for biotechnology

Abstract. Halotolerant or halophilic microorganisms, able to live in saline environments, offer a multitude of actual or potential applications in various fields of biotechnology. The technical applications of bacteriorhodopsin comprise holography, spatial light modulators, optical computing, and optical memories. Compatible solutes are useful as stabilizers of biomolecules and whole cells, salt antagonists, or stress-protective agents. Biopolymers, such as biosurfactants and exopolysaccharides, are of interest for microbially enhanced oil recovery. Other useful biosubstances are enzymes, such as new isomerases and hydrolases, that are active and stable at high salt contents. Halotolerant microorganisms play an essential role in food biotechnology for the production of fermented food and food supplements. The degradation or transformation of a range of organic pollutants and the production of alternative energy are other fields of applications of these groups of extremophiles.

Biodegradation and bioremediation of hydrocarbons in extreme environments

Abstract. Many hydrocarbon-contaminated environments are characterized by low or elevated temperatures, acidic or alkaline pH, high salt concentrations, or high pressure. Hydrocarbon-degrading microorganisms, adapted to grow and thrive in these environments, play an important role in the biological treatment of polluted extreme habitats. The biodegradation (transformation or mineralization) of a wide range of hydrocarbons, including aliphatic, aromatic, halogenated and nitrated compounds, has been shown to occur in various extreme habitats. The biodegradation of many components of petroleum hydrocarbons has been reported in a variety of terrestrial and marine cold ecosystems. Cold-adapted hydrocarbon degraders are also useful for wastewater treatment. The use of thermophiles for biodegradation of hydrocarbons with low water solubility is of interest, as solubility and thus bioavailability, are enhanced at elevated temperatures. Thermophiles, predominantly bacilli, possess a substantial potential for the degradation of environmental pollutants, including all major classes. Indigenous thermophilic hydrocarbon degraders are of special significance for the bioremediation of oil-polluted desert soil. Some studies have investigated composting as a bioremediation process. Hydrocarbon biodegradation in the presence of high salt concentrations is of interest for the bioremediation of oil-polluted salt marshes and industrial wastewaters, contaminated with aromatic hydrocarbons or with chlorinated hydrocarbons. Our knowledge of the biodegradation potential of acidophilic, alkaliphilic, or barophilic microorganisms is limited.

Solubilization of inorganic phosphates by microorganisms isolated from forest soils

Abstract Two strains (a Penicillium sp. and a Pseudomonas sp.) having high abilities to solubilize inorganic phosphates (hydroxylapatite and calcium hydrogenphosphate dihydrate) were screened from 600 colonies isolated from forest soils. Some of their physiological properties (nutrition, O 2 -demand, temperature) were investigated. It was possible to distinguish between solubilization through release of organic acids and still unknown mechanisms. Artificial acidification of the culture medium with HCl did not cause considerable P solubilization compared with our two isolates. In nonsterile soil both organisms caused a marked increase in the P fraction extracted with Licl solution.

Monitoring of bioremediation by soil biological activities.

An evaluation of soil biological activities as a monitoring instrument for the decontamination process of a mineral-oil-contaminated soil was made using measurements of microbial counts, soil respiration, soil biomass and several enzyme activities. The correlations between these parameters and with the levels of hydrocarbon residues were investigated; the effects of different N- and P-sources on hydrocarbon decontamination and soil biological activities were determined. Inorganic nutrients stimulated hydrocarbon biodegradation but not all biological activities to a significant extent. Biodegradation could be monitored well by soil biological parameters: the residual hydrocarbon content correlated positively with soil respiration, biomass-C (substrate-induced respiration), and with activities of soil dehydrogenase, urease and catalase. Soil lipase activity and the number of hydrocarbon utilizers correlated negatively (P < 0.0001) with the remaining hydrocarbon content.

Xylanase-, CM-cellulase- and invertase activity in soil: an improved method.

We present a method for the quantification of xylanase-, CM-cellulase- or invertase activities of soils. It is possible to offer a simple, sensitive (2.8 μg glucose ml−1 assay mixture) and reproducible determination of the enzyme potentials of soils used by agriculture and forestry. The determination of the activity is carried out via the substrate (xylane, CM-cellulose or sucrose), the reaction is performed at pH 5.5 and 50 C. The reducing sugars are measured colorimetrically after reaction with a potassium ferric hexa-cyanide reagent. Additional investigations confirm the high stability of the soil enzyme cellulase, and further the high correlation of this enzyme, and of the xylanase, with the humus content of 7 different soils.

Characterization of Hydrocarbon-Degrading Microbial Populations in Contaminated and Pristine Alpine Soils

ABSTRACT Biodegradation of petroleum hydrocarbons in cold environments, including Alpine soils, is a result of indigenous cold-adapted microorganisms able to degrade these contaminants. In the present study, the prevalence of seven genotypes involved in the degradation of n-alkanes (Pseudomonas putida GPo1 alkB; Acinetobacter spp. alkM; Rhodococcus spp. alkB1, and Rhodococcus spp. alkB2), aromatic hydrocarbons (P. putida xylE), and polycyclic aromatic hydrocarbons (P. putida ndoB and Mycobacterium sp. strain PYR-1 nidA) was determined in 12 oil-contaminated (428 to 30,644 mg of total petroleum hydrocarbons [TPH]/kg of soil) and 8 pristine Alpine soils from Tyrol (Austria) by PCR hybridization analyses of total soil community DNA, using oligonucleotide primers and DNA probes specific for each genotype. The soils investigated were also analyzed for various physical, chemical, and microbiological parameters, and statistical correlations between all parameters were determined. Genotypes containing genes from gram-negative bacteria (P. putida alkB, xylE, and ndoB and Acinetobacter alkM) were detected to a significantly higher percentage in the contaminated (50 to 75%) than in the pristine (0 to 12.5%) soils, indicating that these organisms had been enriched in soils following contamination. There was a highly significant positive correlation (P < 0.001) between the level of contamination and the number of genotypes containing genes from P. putida and Acinetobacter sp. but no significant correlation between the TPH content and the number of genotypes containing genes from gram-positive bacteria (Rhodococcus alkB1 and alkB2 and Mycobacterium nidA). These genotypes were detected at a high frequency in both contaminated (41.7 to 75%) and pristine (37.5 to 50%) soils, indicating that they are already present in substantial numbers before a contamination event. No correlation was found between the prevalence of hydrocarbon-degradative genotypes and biological activities (respiration, fluorescein diacetate hydrolysis, lipase activity) or numbers of culturable hydrocarbon-degrading soil microorganisms; there also was no correlation between the numbers of hydrocarbon degraders and the contamination level. The measured biological activities showed significant positive correlation with each other, with the organic matter content, and partially with the TPH content and a significant negative correlation with the soil dry-mass content (P < 0.05 to 0.001).

Solubilization of inorganic calcium phosphates—Solubilization mechanisms

Abstract Two species [Penicillium aurantiogriseum and Pseudomonas sp. ( PI18 89 )] having high abilities in solubilizing inorganic phosphates (hydroxylapatite and brushite) were used to examine solubilization mechanisms. No direct contact between microorganisms and calcium phosphates (Ca-Ps) were necessary for effective solubilization. The P-concentration in solution did not increase according to a sigmoid curve type. Therefore, sampling time is of particular importance for estimating P mobilization. The widespread theory that solubilization is always caused by the release of organic acids may prove wrong for our two organisms. In our opinion the most probable reason for solubilization without acid production is the release of protons accompanying respiration or NH4+ assimilation. It was shown that solubilization of Ca-Ps with two different solubility products may lead to a short-term increase of the amount of at least one CaP. Precipitation and subsequent resolubilization of different organic or inorganic phosphates result in hardly predictable P-concentrations in culture solution.

Bioremediation (Natural Attenuation and Biostimulation) of Diesel-Oil-Contaminated Soil in an Alpine Glacier Skiing Area

ABSTRACT We investigated the feasibility of bioremediation as a treatment option for a chronically diesel-oil-polluted soil in an alpine glacier area at an altitude of 2,875 m above sea level. To examine the efficiencies of natural attenuation and biostimulation, we used field-incubated lysimeters (mesocosms) with unfertilized and fertilized (N-P-K) soil. For three summer seasons (July 1997 to September 1999), we monitored changes in hydrocarbon concentrations in soil and soil leachate and the accompanying changes in soil microbial counts and activity. A significant reduction in the diesel oil level could be achieved. At the end of the third summer season (after 780 days), the initial level of contamination (2,612 ± 70 μg of hydrocarbons g [dry weight] of soil−1) was reduced by (50 ± 4)% and (70 ± 2)% in the unfertilized and fertilized soil, respectively. Nonetheless, the residual levels of contamination (1,296 ± 110 and 774 ± 52 μg of hydrocarbons g [dry weight] of soil−1 in the unfertilized and fertilized soil, respectively) were still high. Most of the hydrocarbon loss occurred during the first summer season ([42 ± 6]% loss) in the fertilized soil and during the second summer season ([41 ± 4]% loss) in the unfertilized soil. In the fertilized soil, all biological parameters (microbial numbers, soil respiration, catalase and lipase activities) were significantly enhanced and correlated significantly with each other, as well as with the residual hydrocarbon concentration, pointing to the importance of biodegradation. The effect of biostimulation of the indigenous soil microorganisms declined with time. The microbial activities in the unfertilized soil fluctuated around background levels during the whole study.