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The behavior of tetracyclines and their degradation products during swine manure composting 总被引:16,自引:0,他引:16
The purposes of this study were to investigate the behavior of three tetracyclines including chlortetracycline (CTC), oxytetracycline (OTC) and tetracycline (TC) and their degradation products in a pilot scale swine manure composting, and also to study the degradation kinetics of CTC, OTC and TC. During the pilot scale composting, CTC, OTC and TC were degraded by 74%, 92% and 70%, respectively. Several degradation products were found like 4-epitetracycline (ETC), 4-epioxytetracycline (EOTC), 4-epichlortetracycline (ECTC), demeclocycline (DMCTC) and anhydrotetracycline (ATC). Both the simple and the adjusted first-order kinetic models successfully fit the degradation process of CTC, OTC and TC during the composting, but the adjusted first-order kinetic model fit much better with the calculated half-lives of 8.2, 1.1 and 10.0 days, respectively. 相似文献
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The biodegradability of poly(epsilon-caprolactone) (PCL) was studied in blends and composites of modified and granular starch. Four types of PCL-starch compositions were prepared: (i) PCL-granular starch blends; (ii) hydrophobic coating of starch particles by n-butylisocyanate (C(4) starch) and octadecyltrichlorosilane (C(18) starch), followed by melt blending with PCL; (iii) PCL-starch blends compatibilized by PCL-g-dextran grafted copolymer (PGD); and (iv) PCL-grafted starch particles (PGS) as obtained by in situ ring-opening polymerization of caprolactone (CL) initiated directly from hydroxyl functions at the granular starch surface. Biodegradability of these materials was measured by monitoring the percentage of weight loss in composting and the rate of fungal colonization when samples were used as a sole carbon source for fungus (A. niger). Intrinsic viscosity [eta] of host PCL chains was measured after extraction of composted samples in boiled chloroform. SEM was used to study the surface morphology after compost incubation of the samples. The inherent biodegradability of host polymer was enhanced with surface compatibilization during composting for longer incubation. It was observed that the weight loss during composting increased with the decrease in interfacial tension between filler and polymer. In general, it was concluded that inherent biodegradability does not depend very significantly on the concentration of starch in the polyester matrix, but on the compatibilization efficiency. The effect of the PCL fraction in the graft copolymer, when used as compatibilizer, was also studied on the biodegradability of the host polymer. 相似文献
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Céline M. O’Gorman 《Fungal Biology Reviews》2011,25(3):151-157
Aspergillus fumigatus is an opportunistic fungal pathogen that causes invasive aspergillosis, a usually fatal infection. The disease has risen in prominence in recent years due to the increasing numbers of severely immunocompromised patients becoming infected. The fungus is ubiquitous in the environment, producing large numbers of conidia that are dispersed in the air. Humans inhale numerous conidia everyday, but infections are not seen in healthy individuals. As inhalation of conidia is the main route of infection, considerable efforts are required to prevent infection in susceptible patients. This review summarises the current knowledge on airborne concentrations of A. fumigatus conidia, their background levels in outdoor air and seasonal distribution patterns. New and established methods of air sampling for airborne A. fumigatus conidia are discussed. Common environmental sources of the fungus are reviewed, including its presence in compost heaps. Finally, the lack of stringent guidelines on the monitoring and control of airborne A. fumigatus concentrations in hospitals is discussed. 相似文献
65.
《Fungal Ecology》2014
In this study, the biodiversity of thermophilous fungi in two different commercial composts was investigated using culture-based methods, denaturing gradient gel electrophoresis (DGGE) and tag-encoded pyrosequencing. 454 pyrosequencing of the internal transcribed spacer (ITS) region recovered a total of 175 OTUs between the two composts. The Ascomycota was the dominant phylum in both composts (90 % of all sequences recovered) with the thermophilic-rich orders Sordariales and Eurotiales being the most numerous. Molecular studies demonstrated the frequent presence of several thermophilic (Scytalidium thermophilum, Myriococcum thermophilum) and thermotolerant (Pseudallescheria boydii, Corynascus verrucosus and Coprinopsis sp.) fungi in the composts, despite the absence of these species from the culture-based analysis. Conversely, Aspergillus fumigatus and Mycocladus corymbifer, which were the dominant species in cultivation analyses, had very low representation in molecular studies. The results show that the previous picture of the dominant thermophilous fungi in compost communities derived from culture-based analysis has been biased, and that composting environments represent a potentially rich resource of novel fungi. 相似文献
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Thodore Wind-Tinbnoma Kabor Sabine Houot Edmond Hien Prosper Zombr Victor Hien Dominique Masse 《Bioresource technology》2010,101(3):154
The effect of raw materials and their proportions in initial mixtures on organic matter (OM) stabilization and nitrogen (N) availability during pit composting in Sub-Saharan Africa was assessed using biochemical fractionation and laboratory incubations to characterize composts sampled throughout the composting process. Stabilization of OM occurred more rapidly in mixtures with slaughter-house wastes, it was progressive in mixture with household refuses while tree leaves compost remained unstable. Carbon mineralization from compost samples was positively correlated to water soluble and hemicellulose-like organic fractions. Mixtures containing large proportions of household refuses reached the highest stability and total N but available N remained weak. Slaughter-house wastes in the initial mixtures made possible to reach good OM stabilization and the largest N availability. The nature of initial mixing influenced composting parameters, OM stabilization and N availability. It is suggested mixing household refuses and slaughter-house wastes with tree leaves to reach better amending and fertilizer qualities of composts. 相似文献
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The aim of this work was to study the biodisintegration degree of different pieces made of a biodegradable thermoplastic material, the polylactic acid (PLA) with and without corn in its composition, is studied. The pieces of different shapes and thicknesses were obtained by both injection and extrusion processes, where also a specific foaming additive of polystyrene was added. The PLA and PLA-corn manufactured pieces were subjected to aerobic degradation at a constant temperature of 58 ± 2 °C for 90 days, following EN 14806 and ISO 20200:2004 Norms. It was found that the pieces made of PLA and PLA with foaming agent had an average biodisintegration degree of 63.6%. With regard to the pieces made of PLA-corn, an average biodisintegration degree of 79.7% was obtained. In this case, the percentage of non degraded material was independent of the size, shape and thickness of the original pieces. 相似文献
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Composting of animal manures and chemical criteria for compost maturity assessment. A review 总被引:21,自引:0,他引:21
New livestock production systems, based on intensification in large farms, produce huge amount of manures and slurries without enough agricultural land for their direct application as fertilisers. Composting is increasingly considered a good way for recycling the surplus of manure as a stabilised and sanitised end-product for agriculture, and much research work has been carried out in the last decade. However, high quality compost should be produced to overcome the cost of composting. 相似文献
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Xiao-yun Jiang Guang-ming Zeng Dan-lian Huang Yang Chen Fang Liu Guo-he Huang Jian-bing Li Bei-dou Xi Hong-liang Liu 《World journal of microbiology & biotechnology》2006,22(9):909-913
Summary To reduce and eliminate the hazards of pentachlorophenol (PCP) to the soil, the method of inoculating free and immobilized white rot fungi, Phanerochaete chrysosporium to PCP-polluted soils was investigated. Three parallel beakers A, B, C are adopted with the same components of soil, yard waste, straw and bran for aerated composting to degrade the PCP in soil. A was with no inoculants as control, B was added with the inoculants of immobilized P.␣chrysosporium, C was inoculated with non-immobilized P. chrysosporium, and additionally D contained only PCP-contaminated soils also as control. By contrastive analyses, the feasibility of applying composting to the bioremediation of the PCP-polluted soil was discussed. From the experimental results, it could be seen that the degradation rate of PCP by the immobilized fungi exceeded 50% at day 9, while that of the non-immobilized fungi achieved the same rate at day 16. However, the final degradation rates of PCP for both of them were beyond 90% at day 60 and that the rate of A was much lower than the others. The above data have shown that the degradation effect of inoculating P. chrysosporium was better than that of no inoculation, and that of the immobilized fungi was better than that of non-immobilized ones. Meanwhile, shown by all the indicators the composts of A, B and C were mature and stabilized at the end of the experiment. Therefore, the method of composting with immobilized P.␣chrysosporium is effective for the bioremediation of PCP-contaminated soil. 相似文献