Dataset Information

Weathering of pyrogenic organic matter induces fungal oxidative enzyme response in single culture inoculation experiments.

ABSTRACT: The addition of pyrogenic organic matter (PyOM), the aromatic carbon-rich product of the incomplete combustion of plant biomass or fossil fuels, to soil can influence the rate of microbial metabolism of native soil carbon. The interaction of soil heterotrophs with PyOM may be governed by the surficial chemical and physical properties of PyOM that evolve with environmental exposure. We present results of a 36-day laboratory incubation investigating the interaction of a common white-rot fungus, Trametes versicolor, with three forms of 13C-enriched (2.08 atom% 13C) PyOM derived from Pinus ponderosa (450 °C): one freshly produced, and two artificially weathered (254 nm, UV light-water treatment and water-leaching alone). Analysis (FTIR, XPS) of the UV-weathered PyOM showed increased aliphatic C-H content and oxidation of aromatic carbon relative to both the original and water-leached PyOM. The addition of both weathered forms of PyOM stimulated (positively primed) fungal respiration of the growth media, while the unaltered PyOM mildly inhibited (negatively primed) respiration. Artificial weathering resulted in higher oxidative (laccase and peroxidase) enzyme activity than unaltered PyOM, possibly the result of a diminished capacity to bind reactive substrates and extracellular enzymes after weathering. However, and contrary to expectations, simple water-leached weathering resulted in a relatively higher enzyme activity and respiration than that of UV-weathering. The 13C content of respired CO2 indicated negligible fungal oxidation of PyOM for all treatments, demonstrating the overall low microbial reactivity of this high temperature PyOM. The increased enzymatic and positive priming response of T. versicolor to weathered PyOM highlights the importance of weathering-induced chemistry in controlling PyOM-microbe-soil carbon interactions.

SUBMITTER: Gibson C

PROVIDER: S-EPMC5897110 | biostudies-literature | 2016 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Weathering of pyrogenic organic matter induces fungal oxidative enzyme response in single culture inoculation experiments.

Gibson Christy C Berry Timothy D TD Wang Ruzhen R Spencer Julie A JA Johnston Cliff T CT Jiang Yong Y Bird Jeffrey A JA Filley Timothy R TR

Organic geochemistry 20151212

The addition of pyrogenic organic matter (PyOM), the aromatic carbon-rich product of the incomplete combustion of plant biomass or fossil fuels, to soil can influence the rate of microbial metabolism of native soil carbon. The interaction of soil heterotrophs with PyOM may be governed by the surficial chemical and physical properties of PyOM that evolve with environmental exposure. We present results of a 36-day laboratory incubation investigating the interaction of a common white-rot fungus, <i ...[more]

PMID: 29657346

Similar Datasets

Project description:Wildfire greatly impacts the composition and quantity of organic carbon stocks within watersheds. Most methods used to measure the contributions of fire altered organic carbon-i.e. pyrogenic organic carbon (Py-OC) in natural samples are designed to quantify specific fractions such as black carbon or polyaromatic hydrocarbons. In contrast, the CuO oxidation procedure yields a variety of products derived from a variety of precursors, including both unaltered and thermally altered sources. Here, we test whether or not the benzene carboxylic acid and hydroxy benzoic acid (BCA) products obtained by CuO oxidation provide a robust indicator of Py-OC and compare them to non-Py-OC biomarkers of lignin. O and A horizons from microcosms were burned in the laboratory at varying levels of fire severity and subsequently incubated for 6 months. All soils were analyzed for total OC and N and were analyzed by CuO oxidation. All BCAs appeared to be preserved or created to some degree during burning while lignin phenols appeared to be altered or destroyed to varying extents dependent on fire severity. We found two specific CuO oxidation products, o-hydroxybenzoic acid (oBd) and 1,2,4-benzenetricarboxylic acid (BTC2) that responded strongly to burn severity and withstood degradation during post-burning microbial incubations. Interestingly, we found that benzene di- and tricarboxylic acids (BDC and BTC, respectively) were much more reactive than vanillyl phenols during the incubation as a possible result of physical protection of vanillyl phenols in the interior of char particles or CuO oxidation derived BCAs originating from biologically available classes of Py-OC. We found that the ability of these compounds to predict relative Py-OC content in burned samples improved when normalized by their respective BCA class (i.e. benzene monocarboxylic acids (BA) and BTC, respectively) and when BTC was normalized to total lignin yields (BTC:Lig). The major trends in BCAs imparted by burning persisted through a 6 month incubation suggesting that fire severity had first order control on BCA and lignin composition. Using original and published BCA data from soils, sediments, char, and interfering compounds we found that BTC:Lig and BTC2:BTC were able to distinguish Py-OC from compounds such as humic materials, tannins, etc. The BCAs released by the CuO oxidation procedure increase the functionality of this method in order to examine the relative contribution of Py-OC in geochemical samples.

Project description:Microbes that colonize pyrogenic organic matter (PyOM) (also called biochar) play an important role in PyOM mineralization and crucially affect soil biogeochemical cycling, while the microbial community composition associated with PyOM particles is poorly understood. We generated two manure-based PyOMs with different characteristics (PyOM pyrolyzed at the low temperature of 300°C [i.e., PyOM300] and at the high temperature of 700°C [i.e., PyOM700]) and added them to high-carbon (4.15%) and low-C (0.37%) soil for microbial colonization. 16S rRNA gene sequencing showed that Actinobacteria, particularly Actinomycetales, was the dominant taxon in PyOM, regardless of the PyOM pyrolysis temperature and soil type. Bacterial communities associated with PyOM particles from high-C soils were similar to those in non-PyOM-amended soils. PyOM300 had higher total microbial activity and more differential bacterial communities than PyOM700. More bacterial operational taxonomic units (OTUs) preferentially thrived on the low-pyrolysis-temperature PyOM, while some specific OTUs thrived on high-pyrolysis-temperature PyOM. In particular, Chloroflexi species tended to be more prevalent in high-pyrolysis-temperature PyOM in low-C soils. In conclusion, the differences in colonized bacterial community composition between the different PyOMs were strongly influenced by the pyrolysis temperatures of PyOM, i.e., under conditions of easily mineralizable C or fused aromatic C, and by other properties, e.g., pH, surface area, and nutrient content. IMPORTANCE Pyrogenic organic matter (PyOM) is widely distributed in soil and fluvial ecosystems and plays an important role in biogeochemical cycling. Many studies have reported changes in soil microbial communities stimulated by PyOM, but very little is known about the microbial communities associated with PyOM. The microbes that colonize PyOMs can participate in the mineralization of PyOM, so changing its structure affects the fate of PyOMs and contributes to soil biogeochemical cycling. This study identified the bacterial community composition associated with PyOMs on the basis of high-throughput sequencing and demonstrated that both PyOM pyrolysis temperature and the colonization environment determined the bacterial community composition. Our work increases our understanding of the dominant phylogenetic taxa associated with PyOMs, demonstrates mechanisms mediating microbial metabolism and growth in PyOMs, and expands a new research area for pyrogenic organic matter. This study identified the bacterial community composition associated with PyOM, which is widely distributed in the environment. Most bacterial OTUs preferentially thrived on PyOM pyrolyzed at low temperature, while some specific OTUs thrived on PyOM pyrolyzed at high temperature.

Project description:The biodegradability of terrigenous dissolved organic matter (tDOM) exported to the sea has a major impact on the global carbon cycle, but our understanding of tDOM bioavailability is fragmentary. In this study, the effects of preparative tDOM isolation on microbial decomposition were investigated in incubation experiments consisting of mesocosms containing mesohaline water from the Baltic Sea. Dissolved organic carbon (DOC) consumption, molecular DOM composition, bacterial activities, and shifts in bacterial community structure were compared between mesocosms supplemented with riverine tDOM, either as filtered, particle-free river water or as a concentrate obtained by lyophilization/tangential ultrafiltration, and those containing only Baltic Sea water or river water. As shown using ultra-high-resolution mass spectrometry (15 Tesla Fourier-transform ion cyclotron resonance mass spectrometry, FT-ICR-MS) covering approximately 4600 different DOM compounds, the three DOM preparation protocols resulted in distinct patterns of molecular DOM composition. However, despite DOC losses of 4-16% and considerable bacterial production, there was no significant change in DOM composition during the 28-day experiment. Moreover, tDOM addition affected neither DOC degradation nor bacterial dynamics significantly, regardless of the tDOM preparation. This result suggested that the introduced tDOM was largely not bioavailable, at least on the temporal scale of our experiment, and that the observed bacterial activity and DOC decomposition mainly reflected the degradation of unknown, labile, colloidal and low-molecular weight DOM, both of which escape the analytical window of FT-ICR-MS. In contrast to the different tDOM preparations, the initial bacterial inoculum and batch culture conditions determined bacterial community succession and superseded the effects of tDOM addition. The uncoupling of tDOM and bacterial dynamics suggests that mesohaline bacterial communities cannot efficiently utilize tDOM and that in subarctic estuaries other factors are responsible for the removal of imported tDOM.

Dataset Information

Weathering of pyrogenic organic matter induces fungal oxidative enzyme response in single culture inoculation experiments.

Publications

Weathering of pyrogenic organic matter induces fungal oxidative enzyme response in single culture inoculation experiments.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets