Wood ash amendment to biogas reactors as an alternative to landfilling? A preliminary study on changes in process chemistry and biology.

Wood ash addition to biogas plants represents an alternative to commonly used landfilling by improving the reactor performance, raising the pH and alleviating potential limits of trace elements. This study is the first on the effects of wood ash on reactor conditions and microbial communities in cattle slurry-based biogas reactors. General process parameters [temperature, pH, electrical conductivity, ammonia, volatile fatty acids, carbon/nitrogen (C/N), total solids (TS), volatile solids, and gas quantity and quality] were monitored along with molecular analyses of methanogens by polymerase chain reaction- denaturing gradient gel electrophoresis and modern microarrays (archaea and bacteria).

Impacts of 3 years of elevated atmospheric CO2 on rhizosphere carbon flow and microbial community dynamics.

Carbon (C) uptake by terrestrial ecosystems represents an important option for partially mitigating anthropogenic CO2 emissions. Short-term atmospheric elevated CO2 exposure has been shown to create major shifts in C flow routes and diversity of the active soil-borne microbial community. Long-term increases in CO2 have been hypothesized to have subtle effects due to the potential adaptation of soil microorganism to the increased flow of organic C.

Palatability of selected alpine plant litters for the decomposer Lumbricus rubellus (Lumbricidae).

On alpine pastureland the decline in large-bodied earthworm numbers and biomass after abandonment of management might be the result of a shift from highly palatable grass litter to poorly digestible leaf litter of dwarf shrubs. To test this hypothesis, we analysed nitrogen, phosphorous and total phenolic contents of fresh and aged litter of eight commonly occuring alpine plant species and compared consumption rates of these food sources in a controlled feeding experiment with Lumbricus rubellus (Lumbricidae). Furthermore, we analysed the microbial community structure of aged litter materials to check for a relationship between the microbial characteristics of the different plant litter types and the food choice of earthworms.

Searching for links in the biotic characteristics and abiotic parameters of nine different biogas plants.

To find links between the biotic characteristics and abiotic process parameters in anaerobic digestion systems, the microbial communities of nine full-scale biogas plants in South Tyrol (Italy) and Vorarlberg (Austria) were investigated using molecular techniques and the physical and chemical properties were monitored. DNA from sludge samples was subjected to microarray hybridization with the ANAEROCHIP microarray and results indicated that sludge samples grouped into two main clusters, dominated either by Methanosarcina or by Methanosaeta, both aceticlastic methanogens. Hydrogenotrophic methanogens were hardly detected or if detected, gave low hybridization signals.

Budvicia diplopodorum sp. nov. and emended description of the genus Budvicia.

A Gram-negative, rod-shaped, weakly motile, non-spore-forming bacterium (D9(T)) was isolated from the gut of Cylindroiulus fulviceps (Diplopoda) on 1/3-strength nutrient agar plates. On the basis of 16S rRNA gene sequence similarity, strain D9(T) was shown to be phylogenetically closely related to the type strain of Budvicia aquatica, the sole species of the genus Budvicia, family Enterobacteriaceae. The similarity of the 16S rRNA gene sequences of strain D9(T) and B.

Application of COMPOCHIP microarray to investigate the bacterial communities of different composts.

A microarray spotted with 369 different 16S rRNA gene probes specific to microorganisms involved in the degradation process of organic waste during composting was developed. The microarray was tested with pure cultures, and of the 30,258 individual probe-target hybridization reactions performed, there were only 188 false positive (0.62%) and 22 false negative signals (0.

Removal of free extracellular DNA from environmental samples by ethidium monoazide and propidium monoazide.

Recently, new DNA extraction techniques (using ethidium monoazide and propidium monoazide) have been developed to discriminate between alive and dead bacterial cells. Nevertheless, for complex environmental samples, no data are available yet. In the present study, these new methods were applied to anaerobic-fermentor sludge and the results were compared to a conventional microbiological approach.