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Quantification of nutrient and mass loss during composting is needed to understand the composting process, to implement methods for nutrient conservation, and to reduce potential adverse environmental impact. Beef cattle feedlot manure was composted in a windrow on an open concrete area in 1992, 1993, and 1994 to determine the amounts of nutrient, C, and mass loss during composting. The area was enclosed on all sides with a 0.2 m high metal sheet to direct runoff to a fiberglass tank (4000 L) during rainfall. Nutrients in runoff represented combined runoff and leaching losses. Nutrients, C, and mass loss during composting was determined by the difference between the amounts at the beginning and at the end of the composting. Nitrogen loss during composting ranged from 19 to 42% and was related to the initial manure N content. Ammonia volatilization (calculated by difference) accounted for 92% of the N loss whereas combined runoff nitrate and ammonium loss was 0.5%. Mass loss was relatively low (15-20%) while C loss ranged from 46 to 62% and was basically all through bio-oxidation. Phosphorus runoff loss, the main mechanism for P loss, was low ( 2%). Manure N/P ratio decreased during composting, indicating a greater soil P buildup potential with compost application. Potassium and Na losses in runoff were high ( 6.5% each) in 1992 and 1993: they were low ( 2% each) in 1994 due to fewer rainfall. Calcium and Mg losses were 6% each year. Nutrient and salt loss during composting resulted in reduced electrical conductivity of the composted manure. Ammonium and P concentrations in runoff would create surface water pollution if runoff was not diluted with fresh water

In the vermicomposting of paper mill sludge, the activity of earthworms is very dependent on dietetic polysaccharides including cellulose as energy sources. Most of these polymers are degraded by the host microbiota and considered potentially important source for cellulolytic enzymes. In the present study, a metagenomic library was constructed from vermicompost (VC) prepared with paper mill sludge and dairy sludge (fresh sludge, FS) and functionally screened for cellulolytic activities. Eighteen cellulase expressing clones were isolated from about 89,000 fosmid clones libraries. A short fragment library was constructed from the most active positive clone (cMGL504) and one open reading frame (ORF) of 1,092 bp encoding an endo-b-1,4-glucanase was indentified which showed 88% similarity with Cellvibrio mixtus cellulase A gene. The endo-b-1,4-glucanase cmgl504 gene was overexpressed in Escherichia coli. The purified recombinant cmgl504 cellulase displayed activities at a broad range of temperature (25-55℃) and pH (5.5'8.5). The enzyme degraded carboxymethyl cellulose (CMC) with 15.4 U, while having low activity against avicel. No detectable activity was found for xylan and laminarin. The enzyme activity was stimulated by potassium chloride. The deduced protein and three-dimensional structure of metagenome-derived cellulase cmgl504 possessed all features, including general architecture, signature motifs, and N-terminal signal peptide, followed by the catalytic domain of cellulase belonging to glycosyl hydrolase family 5 (GHF5). The cellulases cloned in this work may play important roles in the degradation of celluloses in vermicomposting process and could be exploited for industrial application in future.

Abstract Microbial biomass and community structure were investigated in two composts using the phospholipid fatty acid technique. The composts consisted of shredded straw of Miscanthus with the addition of pig slurry to give an initial C:N ratio of about 25. Samples were taken following changes in the compost temperature (at 5°C intervals) during the first month of composting and additionally after 2 and 3 months. The total microbial biomass, measured as total amount of phospholipid fatty acid, peaked after 1 day with about six times the initial values. The temperature also peaked after 1 day, being above 60°C, and then slowly declined to around 25°C over 3 months. Microbial biomass was approximately halved during this time. When the total amount of phospholipid fatty acid was separated into indicator phospholipid fatty acids for different groups of microorganisms, these groups showed different patterns during the composting process. Gram-positive bacteria increased rapidly with increasing temperature and decreased with decreasing temperature. Gram-negative bacteria and fungi increased initially up to a temperature around 50°C, but decreased during the extreme heating phase. When the temperature declined to about 50°C, the amounts of phospholipid fatty acids indicative of these two groups increased again. The phospholipid fatty acid indicative of actinomycetes, 10Me18:0, was at a low level during the whole experiment, but increased slightly during the last month of composting. The development of the microbial community in the two composting systems was similar during the initial thermophilic phase of the composting process, but the communities after 3 months differed.

Description du sujet. Le bilan des nutriments, l’homogénéité des andains ainsi que l’hygiénisation, évaluée par la température, de composts obtenus lors du co-compostage de boues de laiterie et de fumier de bovins ont été étudiés à la demande de l’industrie laitière réunionnaise qui souhaite développer la valorisation agronomique des boues de laiterie en satisfaisant les contraintes règlementaires de l’Ile de la Réunion. Objectifs. Les objectifs de cette expérimentation étaient d’évaluer la faisabilité d’un co-compostage de fumier de bovin avec des boues de laiterie et de statuer sur la qualité du compost produit. Méthode. Trois andains de fumier avec deux doses de boues de laiterie ont été mis en place (sur une base massique) : fumier seul (T), fumier ⅔ + boues ⅓ (B1) et fumier ½ + boues ½ (B2) présentant une densité brute de 305, 566 et 630 kg·m-3 et une porosité libre à l’air de 72 %, 48 % et 42 %, respectivement. Un retournement a été effectué après 21 jours. Le compostage a été prolongé durant 142 jours.Résultats. Les résultats obtenus montrent que les températures des tas atteignent 70 °C après deux jours de compostage et que l’hygiénisation (t > 55 °C) dure 40, 29 et 34 jours pour les andains T, B1et B2, respectivement. L’andain T a perdu 69 % de sa masse et 64 % de son volume initial pendant le compostage, l’andain B1, 71 % et 44 % et l’andain B2, 68 % et 49 %, respectivement. Les matières minérales et les éléments fertilisants se sont concentrés dans la matière sèche (MS). L’andain T a perdu 54 % de sa matière organique (MO) et 15 % de son azote (N), l’andain B1, 51 % et 42 % et l’andain B2, 56 % et 50 %, respectivement. Les teneurs en MS et en N deviennent plus homogènes au sein du tas pour les andains T et B1 contrairement au tas B2.Conclusions. Les composts obtenus sont conformes à la norme NFU 44-051 (T) et à la norme NFU 44-095 (B1 et B2), sauf pour le critère de teneur en MS pour ces derniers. Par rapport au compost de fumier de bovin, le compost avec ajout de boues (⅓) est enrichi (sur une base matière fraiche) en N (+ 15 %), en P (+ 40 %) et appauvri en K (- 20 %). Co-composting of sludge and dairy cattle manure in Réunion (France): sanitization, nutriment losses and compost homogeneityDescription of the subject. Nutrient balance, windrow homogeneity and the sanitization of composts obtained from the co-composting of dairy sludge and cattle manure were investigated in Réunion at the request of the island's dairy industry, which wants both to develop the agronomic valorization of dairy sludge and to satisfy regulatory constraints on the island. Objectives. The aims of this experiment were to evaluate the feasibility of co-composting cattle manure with dairy sludge and to determine the quality of the compost produced.Method. Three heaps of manure with two doses of dairy sludge were established (on a mass basis): manure alone (T), manure ⅔ + sludge ⅓ (B1) and manure ½ + sludge ½ (B2), with a bulk density of 305, 566 and 630 kg·m-3 and a free air space of 72%, 48% and 42%, respectively. The heaps were turned after 21 days. Total composting time was 142 days. Results. During the experimentation, the temperature remained high and above 55°C for 40 days for the pure manure heap T, for 29 days for heap B1 and for 34 days for heap B2. During composting, heap T lost 69% of its wet mass and 64% of its initial volume, while heap B1 lost 71% and 44% and B2 lost 68% and 49%, respectively. Heap T lost 54% of its organic matter (OM) and 15% of its initial nitrogen (N); the respective levels of loss for B1 were 51% and 42% and for B2 56% and 50%. The heterogeneity of the dry matter (DM) and N content decreased during composting for heaps T and B1, whereas it increased for heap B2. Conclusions. The composts obtained were in accordance with the French standard NFU 44-051 (T) and the French standard NFU 44-095 (B1 and B2), except for the DM content criterion for B1 and B2. Relative to bovine manure compost, compost with the addition of sludge (⅓) was found to be enriched (on a fresh weight basis) in N (+ 15%), in P (+ 40%), whereas it was depleted in K (- 20%).

The biodegradability of poly-β-hydroxybutyrate (PHB), poly-β-hydroxybutyrate-co-valerate (PHB-V) and poly--caprolactone (PCL) were examined following thermal aging in an oven for 192, 425 and 600 h. Different temperatures, 100, 120 and 140°C for PHB and PHB-V and 30, 40 and 50^sup o^C for PCL were used to assess the influence of this parameter on biodegradation. The biodegradability tests were done in soil compostage at pH 11.0 and involved measuring the residual mass of polymer. Thermal analysis of the polymers was done using a differential scanning calorimeter (DSC). The melting temperature and crystallinity were also determined. Thermal ageing increased the biodegradability only for PHB at 120 and 140^sup o^C, and there was no correlation between crystallinity and the biodegradation of the polymers.[PUBLICATION ABSTRACT]

Principal chemical indices of compost associated with compost stabilization were investigated using relationship between stability degree (SD) and chemical indices including pH, electrical conductivity (EC), total C, extractable C, decomposability, total N, NH4+, NO3−, molar ratio of NH4+ to NO3−, C/N, total P, and soluble P of various composts. Compost SD was positively (p<0.05) correlated with pH and C/N, and negatively (p<0.05) with EC, total N, and molar ratio of NH4+ to NO3−. However, the correlation with pH, C/N, and total N were in contradiction to other studies that reported an opposite relationship to ours, probably due to different properties of initial composting materials. Therefore, the present study in conjunction with other studies suggest that EC and the molar ratio of NH4+ to NO3− are the chemical indices closely associated with stabilization of composts regardless of composting materials.

Archaeal diversity during the composting process of pig manure and mushroom culture waste using a field-scale composter was investigated by a culture-independent approach. Metagenomes were isolated from six sampling sites at various stages and the 16S rRNA fragments were amplified with archaea-specific primers. Based on their rRNA sequences, a total of 180 clones, 30 clones from each site, could be divided into seven groups. Among them, group I to group V were assigned to the phylum Euryarchaeota, and group VI and group VII to the phylum Crenarchaeota. All the clones of group I (uncultured archaeon clone AE34) and group II (uncultured archaeon clone AS17) belonged to the class Methanomicrobia and the closest neighboring species was allocated to the Methanomicrobium mobile, a methanogen. Two major methanogen groups, I and II, were predominantly present at the initial stage and at the mid to late stages, respectively. The quantified values of their prevalence were 45.0% (81 out of a total of 180 clones) and 47.8% (86 of 180 clones), respectively. Group VI (an uncultured archaeon) and group VII (uncultured archaeon clone AF15) were minor groups and belonged to the class Thermoprotei. Little change in the methanogenic archaeal diversity was observed compared to that of the bacterial and fungal diversity. The results may help to gain information about CH4 production from composting and to improve the fieldscale composter system, since the diversity would be dependent on the maturation and composition of the compost.

The utility of an urban solid waste, either freshly composted or vermicomposted, for improvement of plant growth in a soil B horizon was investigated. Growth, mineral nutrition and arbuscular mycorrhizal (AM) colonization of cucumber and red clover plants were studied in an experiment carried out under controlled growing conditions, using different mixtures of soil and composts as plant substrates. Soil inoculation with the AM fungus Acaulospora sp. did not benefit growth of plants when soil was used as the only substrate, possibly due to its poor fertility. Results showed that neither mycorrhizal plant species grew when soil was mixed with composted urban waste or when compost was used as the only substrate. However, amendment of soil with 10 or 50% vermicompost significantly increased dry matter yields of red clover and cucumber plants, compared to treatments where soil was the only substrate. Addition of vermicompost also increased Olsen-P and other mineral elements in soil and shoot P, Ca, Mg, Cu, Mn and Zn concentrations, but caused a significant reduction on root length colonized by AM fungi in red clover plants. It is concluded that application of high amounts of vermicompost from composted urban wastes to soils might cause a significant reduction of activity of AM fungi, which must be taken into account when using these organic amendments in agricultural systems.

The objective of this study was (a) to detect changes of the functional abilities of the microflora during composting of manure as a result of windrow turning frequency and (b) to detect differences between distinct zones within the windrows. Biolog GN microtiter plates containing 95 different carbon sources were inoculated with diluted suspensions of compost material containing 15,000 microorganisms per well (120 microliter). We found a dramatic shift in functional microbial community structure during the 8-week composting process. The shift was more rapid when the compost windrows were turned. The substrate use pattern in the outer, well-aerated zone of the unturned windrow was similar to that of the turned windrows. Microbial biomass and respiration decreased more rapidly in the turned than in the unturned windrows, indicating a different pace of compost maturation. The data suggest that the Biolog assay may be a suitable approach to determine compost maturity.