Biological oxidation of hydrogen in soils flushed with a mixture of H₂, CO₂, O₂and N₂

Abstract

A stainless steel cylinder filled with soil was flushed upstream with a H2/CO2/air mixture. The consequence was a strong enrichment of the aerobic, autotrophic hydrogen‐oxidising microflora, which reached densities enabling them to oxidize 84.5 ml H2· dm−2· h−1 in the first 25‐cm layer. H2 concentration profiles, hydrogen uptake activity and cell numbers correlated well with each other. Most of the organisms isolated were dinitrogen fixers. Thus, soils containing hydrogen‐oxidising bacteria may act as a biological shield between H2‐rich environments and air, and may be utilized as biofilters, e.g., in the waste‐processing industry.

Hydrogen fertilization of soils – is this a benefit of legumes in rotation?

“…Furthermore, H 2 production from legume nodules induced the H 2 oxidation capacity of soil, and this capacity and H 2 -oxidizing bacteria numbers decreased exponentially with distance from the nodule (La Favre & Focht 1983). Other studies have confirmed that treatment of soil with H 2 results in an enrichment of aerobic, autotrophic H 2 -oxidizing microflora (Dugnani et al 1986). These changes in the bacterial populations in the soils adjacent to H 2 -releasing nodules may be associated with the enhanced growth response of plants that are rotated with legumes in cropping systems.…”

Measurement of Dissolved H2, O2, and CO2 in Groundwater Using Passive Samplers for Gas Chromatographic Analyses

“…Hydrogen Stability in FRC Groundwater Samples . Hydrogen is a ready energy source for microbial growth in soils ( , ) and, thus, its presence at such high concentrations in the FRC groundwater may indicate an inhibition of its normal consumptive processes regardless of whether gener ated by microbial fermentation or by radiolysis or by other reactions in the S-3 ponds' residual sludge. The apparent stability of H 2 in the FRC groundwater is illustrated by a series of groundwater samples, collected in sealed glass bottles from four monitoring wells on March 6, 2006 and analyzed for fixed gases in minimal headspace weekly over the subsequent 8 weeks while stored in the laboratory at room temperature with no preservative treatments (Figure ).…”

Thermophilic bacterial communities in hot composts as revealed by most probable number counts and molecular (16S rDNA) methods

“…The physicochemical evolution of organic matter during the composting process (such as depletion of solubles within the ¢rst weeks Although composting is essentially an aerobic process, anaerobic decomposition is known to occur in micro-environments of the heterogenous, oxygenpoor matrix of the compost itself [41,42]. Moreover, a decreasing gradient of temperature establishes from the core to the outer part of the compost windrow within a few hours after turning [2,43].…”