Evaluation of the transformation of organic matter to humic substances in compost by coupling sec-page

Humic acids (HAs) from soil and compost at the beginning (S0) and at the end of the stabilization process after 130 days (S130) have been fractionated by coupling size exclusion chromatography (SEC) and polyacrylamide gel electrophoresis (PAGE). Preparative quantities of HA fractions (HAFs) with different molecular sizes (MSs) and exactly defined electrophoretic mobility (EMs) have been obtained from all samples and the HAFs weight content has been studied. A high degree of similarity in HAFs weight content between soil HA and a stabilized compost HAs130 has been observed. Such data seem to be reliable for monitoring the evolution of the compost organic matter to humic substances for their agricultural uses.     

Evaluation of photochemical properties of compost humic-like materials

Humic-like acids (HLA) were extracted from compost at the beginning and after 70, 130 and 730 days of maturation in order to be investigated for their ability to induce the transformation of 2,4,6-trimethylphenol under irradiation at 365 nm. The rate of 2,4,6-trimethylphenol phototransformation in the presence of HLA (25 mg l(-1)) varied within HLA 0相似文献   

Transformation of organic matter during co-composting of pig manure with sawdust

Co-composting of pig manure with sawdust was studied in order to characterize the organic transformation during the process, using both chemical and spectroscopic methods. Humic acids (HA) and fulvic acids (FA) were fractionated from immature and mature pig manure compost, and characterized. After 63 days of composting, the ratio of total organic carbon and soluble organic carbon decreased to a satisfactory low level and the solid and soluble C/N ratios decreased rapidly for the first 35 days before attaining a constant value, indicating compost maturity. Humification could be responsible for the increase in humic acid proportion during composting. The increase in the aromatic bonds after composting, as indicated by the reduction of C/H and C/O ratios of HA and FA, resulted in a more stabilized product. A substantial increase in high molecular weight compounds along with a small increase in low molecular weight compounds was found in mature compost. Moreover the HA also had more complex organic compounds at this stage. Fluorescence spectral analysis showed an increase in the maximum wavelength of HA associated with the contents of aromatic structures in solution. A decrease in relative absorbance of HA at 1160 cm(-1), 2950 cm(-1) and 2850 cm(-1) was seen in the FTIR spectra indicating the decomposition of complex organic constituents, into simpler ones. Increase in the aromatic compounds with higher stability could account for the relative increase in the absorbance of HA at 1650 cm(-1) and 1250 cm(-1) of the mature compost. The composition of FA was not much altered, indicating most of the degradation of organic matter occurred in HA. Data from organic carbon, C/N ratio, elemental analysis, E(4)/E(6) ratio, gel chromatography, fluorescence and FTIR spectra indicated an increase in polycondensed structures and the presence of more stable organic matter in the mature compost.     

Characterization of natural organic matter (NOM) derived from sewage sludge compost. Part 1: chemical and spectroscopic properties

In this study changes in the properties of natural organic matter (NOM) were studied during composting of sewage sludge in a laboratory experiment using the pile method. Typical physicochemical parameters were measured during 53 days of composting including humic fractions. The effects of humification on the molecular properties of humic acids (HA) were investigated by 13C CP/MAS NMR spectroscopy. On the basis of chemical analyses, 53 days of composting sewage sludge with structural material can be divided into three phases: (i) domination of rapid decomposition of non-humic, easily biodegradable organic matter (two to three weeks), (ii) domination of organic matter humification and formation of polycondensed, humic-like substances (the next two weeks), (iii) stabilization of transformed organic material and weak microbial activity. Spectroscopic characterization (13C NMR) of compost humic acids reveals changes in their structures during maturation. The changes are highly correlated with the processes taking place in bulk compost.     

Comparison of characterization and microbial communities in rice straw- and wheat straw-based compost for <Emphasis Type="Italic">Agaricus bisporus</Emphasis> production

Rice straw (RS) is an important raw material for the preparation of Agaricus bisporus compost in China. In this study, the characterization of composting process from RS and wheat straw (WS) was compared for mushroom production. The results showed that the temperature in RS compost increased rapidly compared with WS compost, and the carbon (C)/nitrogen (N) ratio decreased quickly. The microbial changes during the Phase I and Phase II composting process were monitored using denaturing gradient gel electrophoresis (DGGE) and phospholipid fatty acid (PLFA) analysis. Bacteria were the dominant species during the process of composting and the bacterial community structure dramatically changed during heap composting according to the DGGE results. The bacterial community diversity of RS compost was abundant compared with WS compost at stages 4–5, but no distinct difference was observed after the controlled tunnel Phase II process. The total amount of PLFAs of RS compost, as an indicator of microbial biomass, was higher than that of WS. Clustering by DGGE and principal component analysis of the PLFA compositions revealed that there were differences in both the microbial population and community structure between RS- and WS-based composts. Our data indicated that composting of RS resulted in improved degradation and assimilation of breakdown products by A. bisporus, and suggested that the RS compost was effective for sustaining A. bisporus mushroom growth as well as conventional WS compost.     

Effects of the maturity of wood waste compost on the structural features of humic acids

An analytical scheme for the separation of humic substances (HSs) and non-humic substances (non-HSs) was established to estimate the humification index (HI), which was defined as the ratio of HS carbon content to non-HS carbon content. The alkaline compost-extract contained a mixture of HSs and non-HSs, while acidification of the compost-extract resulted in precipitation of humic acid (HA). The acidified supernatant contained fulvic acid (FA) and non-HSs. In the present study, DAX-8 resin was used to separate FA and non-HSs. HI values, which were estimated to evaluate the maturity of wood waste compost, increased with composting duration. To determine the effects of compost maturity on HA structural features, correlations between HI and indicators of the degree of HA humification (atomic ratios, acidic functional group contents, spectroscopic parameters and molecular weight) were investigated. HI values were significantly related to the indicators of the extent of HA humification during composting.     

Organic matter transformations and kinetics during sewage sludge composting in a two-stage system

The use of different proportions of rape straw and grass as amendments in the composting of dewatered sewage sludge from a municipal wastewater treatment plant was tested in a two-stage system (first stage, an aerated bioreactor and second stage, a periodically turned windrow). The composition of feedstock affected the temperature and organic matter degradation in the bioreactor and the formation of humic substances, especially humic acids (HA), during compost maturation in the windrow. The total HA content (the sum of labile and stable HA) increased according to first-order kinetics, whereas labile HA content was constant and did not exceed 12% of total HA. Δlog K of 1.0–1.1 indicated that HA was of R-type, indicating a low degree of humification. Temperature during composting was the main factor affecting polymerization of fulvic acids to HA and confirmed the value of the degree of polymerization, which increased only when thermophilic conditions were obtained.     

Electrophoretic subfractionation of low and high molecular weight humic acids fractions

Summary Soil humic acid was fractionated on a molecular weight basis either using Sephadex gel filtration or electrophoresis on a discontinuous polyacrylamide gel. Low and high molecular weight fractions obtained by these two methods were choosen for subsequent subfractionation using electrophoretic methods. The high and low molecular weight fractions yielded several subfractions after separation by isotachophoresis or isoelectric focusing. Components of the high molecular weight fractions occupied the upper portion of the mobility train; components of the low molecular weight fractions lead the mobility train. Adsorption by Sephadex was avoided by using 4M urea as an eluent. The elution of the humic substances adsorbed to the polyacrylamide gel matrix was achieved by using a 0.1M Tris –0.025M EDTA solution.     

Agarose and polyacrylamide gel electrophoresis methods for molecular mass analysis of 5- to 500-kDa hyaluronan

Agarose and polyacrylamide gel electrophoresis systems for the molecular mass-dependent separation of hyaluronan (HA) in the size range of approximately 5–500 kDa were investigated. For agarose-based systems, the suitability of different agarose types, agarose concentrations, and buffer systems was determined. Using chemoenzymatically synthesized HA standards of low polydispersity, the molecular mass range was determined for each gel composition over which the relationship between HA mobility and logarithm of the molecular mass was linear. Excellent linear calibration was obtained for HA molecular mass as low as approximately 9 kDa in agarose gels. For higher resolution separation, and for extension to molecular masses as low as approximately 5 kDa, gradient polyacrylamide gels were superior. Densitometric scanning of stained gels allowed analysis of the range of molecular masses present in a sample as well as calculation of weight-average and number-average values. The methods were validated for polydisperse HA samples with viscosity-average molecular masses of 112, 59, 37, and 22 kDa at sample loads of 0.5 μg (for polyacrylamide) to 2.5 μg (for agarose). Use of the methods for electrophoretic mobility shift assays was demonstrated for binding of the HA-binding region of aggrecan (recombinant human aggrecan G1–IGD–G2 domains) to a 150-kDa HA standard.     

Optimizing composting parameters for nitrogen conservation in composting

A central composite experimental design was used to investigate the influence of environmental composting parameters (moisture, aeration, particle size and time) for legume trimming residues, used on soil restoration, on the properties of products obtained (organic matter, Kjeldahl-N, C/N ratio and nitrogen losses (N-losses)) in order to determine the best composting conditions. A second-order polynomial model consisting of four independent process variables was found to accurately describe (the differences between the experimental values and those estimated by using the equations never exceeded 10% of the former) the composting process. Results of the experiment showed that compost with acceptably chemical properties (OM, 85%; Kjeldahl-N, 3.2%), high degradation and minimum N-losses entails operating at high operation time (78 days), low particle size (1cm), medium moisture content (40%) and medium to low aeration level (0.2-0.4 l air/min kg).     

Methods to improve the composting process of the solid fraction of dairy cattle slurry

Cattle slurry solid fraction (SF) with different dry matter (DM) contents was collected from two dairy farms and composted in static and turned piles, with different sizes and cover types, to investigate the effects of pile conditions on the physical and chemical changes in SF during composting and to identify approaches to improve final compost quality. Thermophilic temperatures were attained soon after separation of SF, but the temperature of piles covered with polyethylene did not increase above 60 degrees C. The rate of organic matter (OM) mineralisation increased for turned piles in comparison to static piles, but the maximum amount of mineralisable OM (630-675gkg(-1)) was similar for all pile treatments. The C/N ratio declined from over 36 to a value of 14 towards the end of composting, indicating an advanced degree of OM stabilisation. Mature compost was obtained from raw SF feedstock as indicated by the low compost temperature, low C/N ratio, and low content of NH(4)(+) combined with increased concentrations of NO(3)(-). The efficiency of the composting process was improved and NH(3)-N losses were minimized by increasing DM content of the SF, reducing the frequency of pile turning and managing compost piles without an impermeable cover.     

Heavy metal contamination of a mixed waste compost: Metal speciation and fate

The aims of this study were to assess changes in heavy metal availability in two contrasting feedstocks during aerobic composting, and the availability of said metals in the finished composts. A high C-to-N ratio mixed biodegradable municipal solid waste (MSW) feedstock was successfully composted on its own and in combination with green waste. Changes in heavy metal speciation throughout the composting process were studied using the modified BCR sequential extraction protocol. It was found that total Cu, Pb and Zn concentrations increased over time due to the progressive mineralization of the compost feedstock. Metals were fractionated differently within the two feedstocks, although only Cu showed significant redistribution (mostly to the oxidisable fraction) over the 5 month composting period. The MSW-derived composts performed comparably with other commercially-available composts in a series of plant growth trials. Plant metal accumulation was not influenced by the heavy metals present in the MSW-derived compost implying that they are not plant available. It is recommended that these relatively low value/quality composts may be used for remediation of acidic heavy metal contaminated sites.     

Degradation of pectic polysaccharides extracted from suspension cultures of carrot by purified exo-polygalacturonase

Highly purified exo-polygalacturonase was obtained from suspension cultures of carrot ( Daucus carota L. cv. Kintoki) by dialysis at pH 5.2, chromatography on DEAE-Sephadex A-50 and on Sephadex G-150, and preparative polyacrylamide disc gel electrophoresis. The enzyme did not attack the isolated carrot cell walls directly, but it had some effect on pectic polysaccharides extracted from the walls. The extracted polysaccharides were fractionated by DEAE-Sephadex A-50 column chromatography yielding four carbohydrate fractions. The major fraction (P-3) was then reacted with the exo-polygalacturonase. The enzyme treatment resulted in hydrolysis of approximately 18% of the glycosyl linkages of fraction P-3 with the release of galacturonic acids. The molecular size estimated by Bio-Gel A-5m gel filtration was not markedly affected by the enzyme action, but the percentage of galacturonosyl residues was clearly reduced. The specific activity of exo-polygalacturonase changed during the growth cycle, in relation to the cell growth.     

Cyclic changes in the charge profile of LH in anterior pituitary glands of adult female Japanese monkeys (Macaca fuscata).

Thirteen adult female Japanese monkeys (Macaca fuscata) were sacrificed in the early and the late follicular phase, and in the mid-luteal phase of the menstrual cycle, and also after castration. Pituitary LH content correlated significantly with plasma estradiol levels but not progesterone levels in the cycling monkeys. Pituitary LH species were fractionated by isoelectrofocusing (1EF). Pituitary LH species were separated into six fractions by IEF. High alkaline LH and alkaline LH were the most abundant species in the late follicular phase and the mid-luteal phase, respectively. Neutral LH and acidic LH were the most abundant in the early follicular phase and in the castrates. Pituitary LH thus changed qualitatively and quantitatively during the menstrual cycle and after castration.     

Humic substances change during the co-composting process of municipal solid wastes and sewage sludge

The change of the degree of stability of compost during the composting process was a kind of guideline for our study. This stability was estimated by monitoring the chemical fractionation (extraction of humic and fulvic acids, and humin) during two cycles of composting. Change of humin (H), humic-like acid carbon (CHA) and fulvic-like acid carbon (CFA) fractions during the composting process of municipal solid wastes were investigated using two windrows W1 (100% of municipal solid wastes) and W2 (60% of municipal solid wastes and 40% of dried sewage sludge). Humin and fulvic acid fractions in the two windrows decreased since the start of composting process and tend to stabilize. At the end of composting process, humic acid fraction is more important in the windrow without sludge (W1) than the one with sludge (W2). The humification indexes used in this study showed that the humic-like acid carbon fraction production takes place largely during the phase of temperature increase (thermophilic phase), and it appeared very active in the windrow W2. At the end of composting process, the E₄/E₆ ratio value indicated that the compost of W1 is more mature than the compost of W2. The humification ratio (HR) allowed a correct estimation of compost organic matter stabilization level.     

Organic matter humification by vermicomposting of cattle manure alone and mixed with two-phase olive pomace

The chemical changes occurring in a cattle manure (CM) and a mixture of two-phase olive pomace and CM (OP+CM) after vermicomposting with Eisenia andrei for eight months were evaluated. Further, humic acid (HA)-like fractions were isolated from the two substrates before and after the vermicomposting process, and analyzed for elemental and acidic functional group composition, and by ultraviolet/visible, Fourier transform infrared and fluorescence spectroscopies. Before vermicomposting, the HA-like fractions featured a prevalent aliphatic character, large C contents, small O and acidic functional group contents, a marked presence of proteinaceous materials and polysaccharide-like structures, extended molecular heterogeneity and small degrees of aromatic ring polycondensation, polymerisation and humification. After vermicomposting, the total extractable C and HA-C contents in the bulk substrates increased, and the C and H contents, aliphatic structures, polypeptidic components and carbohydrates decreased in the HA-like fractions, whereas O and acidic functional group contents increased. Further, an adequate degree of maturity and stability was achieved after vermincomposting, and the HA-like fractions, especially that from OP+CM, approached the characteristics typical of native soil HA. Vermicomposting was thus able to promote organic matter humification in both CM alone and in the mixture OP+CM, thus enhancing the quality of these materials as soil organic amendments.     

Comparison between UV spectroscopy and Nirs to assess humification process during sewage sludge and green wastes co-composting

The humification of organic matter during composting was studied by the quantification and monitoring of the evolution of humic substances (Humic Acid-HA and Fulvic Acid-FA) by UV spectra deconvolution (UVSD) and near-infrared reflectance spectroscopy (NIRS) methods. The final aim of this work was to compare UVSD to NIRS method, already applied on the same compost samples in previous studies. Finally, UVSD predictions were good for HA and HA/FA (r² of 0.828 and 0.531) but very bad for FA (r² of 0.092). In contrary, all NIRS correlations were accurate and significant with r² of 0.817, 0.806 and 0.864 for HA, FA and HA/FA ratio respectively. From these results, HA/FA ratio being a well-used index of compost maturity, UVSD and NIRS represent two invaluable tools for the monitoring of the composting process. However, we can note that NIRS predictions were more accurate than UVSD calibrations.     

Microbiological parameters as indicators of compost maturity

AIMS: The objectives of this study were to determine the changes of microbial properties of pig manure collected from pens with different management strategies and composted using different turning and moisture regimes; relate their association with humification parameters and compost temperature; and identify the most suitable microbial indicators of compost maturity. METHODS AND RESULTS: Six different microbial parameters, including total bacterial count, oxygen consumption rate, ATP content, dehydrogenase activity, and microbial biomass C and N, along with humification parameters [humic acid (HA), fulvic acid (FA) and HA : FA ratio] and compost temperature were monitored during composting. Significant positive correlations were found between temperature and microbial properties, including O2 consumption rate, ATP content, dehydrogenase activity, and microbial biomass N. The humification parameters also showed significant correlations with microbial properties of the manure compost. For instance, HA contents of pig manures was positively correlated with total aerobic heterotrophs, and microbial biomass N and C; and negatively correlated with O2 consumption rate, ATP content, and dehydrogenase activity. Among the six microbial parameters examined, dehydrogenase activity was the most important factor affecting compost temperature and humification parameters. Composting strategies employed in this study affected the speed of composting and time of maturation. If the moisture content is maintained weekly at 60% with a 4-day turning frequency, the pig manure will reach maturity in 56 days. CONCLUSIONS: The composting process went through predictable changes in temperature, microbial properties and chemical components despite differences in the initial pig manure and composting strategies used. Among the six microbial parameters used, dehydrogenase activity is the most suitable indicator of compost maturity. Compared with respiration rate, ATP content and microbial biomass procedures, dehydrogenase activity is the simplest, quickest, and cheapest method that can be used to monitor the stability and maturity of composts. SIGNIFICANCE AND IMPACT OF THE STUDY: The results presented here show that microbial parameters can be used in revealing differences between composts and compost maturity. The statistical relationship established between humification parameters and microbial parameters, particularly dehydrogenase activity, demonstrates that it is possible to monitor the composting process more easily and rapidly by avoiding longer and more expensive analytical procedures.     

Studies on mitochondrial proteins I. Separation and characterization by polyacrylamide gel electrophoresis

Rat liver mitochondria were fractionated into inner and outer membranes and soluble intermembrane space and matrix. The protein components of these fractions were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Mitochondria contained at least 20 components ranging in molecular weights from 10 000 to 140 000. Inner membranes differed markedly from outer membranes both in number of components and size distribution. The intermembrane space contained a few polypeptide species. These were of low molecular weight. The matrix was characterized by a high molecular weight component (130 000) which comprised 30% of this fraction. A major carbohydrate-containing polypeptide with an approximate molecular weight of 93 000 was detected in outer membrane preparations.     

Diversity and Abundance of Ammonia-Oxidizing Bacteria and Ammonia-Oxidizing Archaea During Cattle Manure Composting

Ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) play important roles in nitrification in various environments. They may also be key communities for ammonia oxidation in composting systems, although few studies have discussed their presence. We investigated the relative diversity and abundance of AOB and AOA using cloning procedures, denaturing gradient gel electrophoresis analysis, and real-time PCR during several stages in the process of cattle manure composting. Our results revealed that the AOB community structure changed during the process. At the high-temperature stage (>60°C), a member of the Nitrosomonas europaea/eutropha cluster dominated while the uncultured Nitrosomonas spp. cluster appeared after the temperature decreased. Additionally, our analysis indicated that AOA sequences, which were classified into a soil/sediment cluster, were present after the temperature decreased during the composting process. At these stages, the number of the archaeal amoA gene copies (3.2 or 3.9?×?10⁷ copies per gram freeze-dried compost) was significantly higher than that of bacterial amoA gene copies (2.2–7.2?×?10⁶ copies per gram freeze-dried compost). Our results suggest that both AOB and AOA are actively involved in nitrification of composting systems.