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 (r(2) of 0.828 and 0.531) but very bad for FA (r(2) of 0.092). In contrary, all NIRS correlations were accurate and significant with r(2) 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.

Changes in the level of alkaline and acid phosphatase activities during green wastes and sewage sludge co-composting.

The aim of this work was to study the activity level of alkaline and acid phosphatases during the composting of green wastes and sewage sludge and to determine relationships between biotic and abiotic properties of compost and phosphatase activities. This study has revealed a noticeable separation of phosphomonoesterase activities into two distinct phases during composting. Alkaline and acid phosphatase activities were high during the first month of composting and then declined up to the end of the process. Both phosphatase activities were significantly correlated with a group of variables which are clearly related to advancement of maturity during the composting process: C/N, respiration, cellulase, protease, phenoloxidase activities, HA and Global Index of Composting Evolution (GICE) resulting from 14 biological and chemical parameters. This study has also revealed the complexity of factors regulating turnover of P in compost process since phosphatase activities appeared constrained across two thresholds: 60/70 and 100 microg of inorganic P g(-1) DM for activation and repression, respectively.

Calibration of chemical and biological changes in cocomposting of biowastes using near-infrared spectroscopy.

Cocomposting of green wastes and sewage sludges is a complex process involving rapid biological and chemical changes. The objective of the study was to assess the usefulness of near-infrared reflectance spectroscopy (NIRS) to characterize these changes, as an alternative to standard procedures which are often time-consuming and laborious. Samples obtained during 146 days of composting were analyzed by 14 conventional methods and NIRS. Results from conventional methods demonstrated a noticeable separation into two distinct phases. An initial phase from 4 to 50-60 days was characterized by intensive degradation. A second phase up to 146 days was characterized by a decrease in all biological activities. NIRS calibrations allowed accurate predictions of nitrogen (N), carbon (C), C/N, humic acid (HA), pH, respiration, cellulase, phenoloxidase, and composting time successfully. Results were less accurate for organic matter (OM), protease, acid, and alkaline phosphatases and unsatisfactory for fulvic acid. NIRS calibration allows composting time/state of progress of maturation to be predicted accurately to within 10 days. A global index of composting evolution (GICE), resulting from the 14 parameters studied, is proposed. It is precisely predicted and shows that since NIRS is able to predict essential parameters of compost maturity, it could prove invaluable for monitoring biowastes cocomposting.

Efficiency of near-infrared reflectance spectroscopy to assess and predict the stage of transformation of organic matter in the composting process.

Changes in composts of sewage sludges and green wastes were analysed by near infrared reflectance spectroscopy (NIRS) and chemical analysis with 426 samples representative of six stages of composting: 8, 20, 35, 75, 135 and 180 days. Maturity of compost was assessed through changes in C:N ratio. Results of spectroscopic properties (200 wavelengths) were studied with several multivariate analyses. First, a descriptive approach revealed compost changes with time of maturation. Then, a constrained ordination (RDA with permutation tests) demonstrated a significant effect of three factors of sampling: stage of composting, depth and position in windrows. Precise calibration models between spectral data, the C, N, C:N values and composting time were build using partial least square regression (r(2)>0.95). Together, these results show the efficiency of NIRS to predict chemical changes and the stage of transformation of organic matter during the composting process.

Sewage sludge effects on mesofauna and cork oak (Quercus suber L.) leaves decomposition in a Mediterranean forest firebreak.

Effects of sewage sludge on litter mesofauna communities (Collembola and Acari) and cork oak (Quercus suber L.) leaf litter decomposition have been studied during 18 mo using litterbags in an in situ experimental forest firebreak in southeastern France. The sludge (2.74 t DM ha(-1) yr(-1)) was applied to fertilize and maintain a pasture created on the firebreak. Litterbag colonization had similar dynamics on both the control and fertilized plots and followed a typical Mediterranean pattern showing a greater abundance in spring and autumn and a lower abundance in summer. After 9 mo of litter colonization, Collembola and Acari, but mainly Oribatida, were more abundant on the sludge-fertilized plot. Leaf litter decomposition showed a similar pattern on both plots, but it was faster on the control plot. Furthermore, leaves from the fertilized plot were characterized by greater nitrogen content. Both chemical composition of leaves and sludges and the decomposition state of leaves have significantly affected the mesofauna community composition from each plot.

Degradation of procyanidins by Aspergillus fumigatus: identification of a novel aromatic ring cleavage product.

Aspergillus fumigatus was able to grow on apple-purified procyanidins (PCs). PCs concentration decreased 30% over the first 60 h of liquid fermentation. The mean degree of polymerization (DPn) of apple-purified PCs increased from 8 to 15 during the fermentation. A fungal enzyme extract from the liquid fermentation was used to study procyanidin B2 [(-)-epicatechin-(4beta-8)-(-)-epicatechin] degradation. The major degradation product (PB2-X) had a retention time of 10.5 min and a molecular mass at m/z 609. High-performance liquid chromatography/multiple fragment mass spectrometry (HPLC/MS(n)) was used for the structural characterization of PB2-X as well as that of thiolysis-treated PB2-X. Twelve fragment ions at m/z 565, 547, 457, 439 (two fragment ions), 421, 413, 377, 395, 351, 287 and 277 were completely identified. It was therefore deduced that the terminal unit of procyanidin B2 dimer was modified by an oxygenase from A. fumigatus leaving the extension unit intact. In addition, FT-IR analysis confirmed a lactone formation in (-)-epicatechin moiety involved in oxidative degradation. Two reaction schemes were postulated for the interpretation of the results.

[Temporal variations of physicochemical and microbiological parameters in three freshwater ecosystems (southeastern France) invaded by Ludwigia spp]. / Variations temporelles des paramètres physicochimiques et microbiologiques de trois écosystèmes aquatiques (Sud-Est de la France) envahis par des Ludwigia.

In France, two amphibious hydrophytes of alien Ludwigia (Onagraceae) have for about the past twenty years been causing serious ecological and economic problems: L. peploides (Kunth) Raven et L. grandiflora (Michaux) Greuter & Burdet. This bacteriological and physicochemical study, focused on three different Mediterranean aquatic ecosystems, reveals, for the first time, a direct negative impact of these American invaders. During summer, while plant growth is intensive, and the appearance in the water column of anoxic conditions and production of toxic compounds may be observed, notably in L. grandiflora stands. The toxicity is linked to a proliferation of sulphate-reducing bacteria producing sulphides that are very harmful for aquatic organisms.

Characterization of a low redox potential laccase from the basidiomycete C30.

A new exocellular laccase was purified from the basidiomycete C30. LAC2 is an acidic protein (pI = 3.2) preferentially produced upon a combined induction by copper and p-hydroxybenzoate. The spectroscopic signature (UV/visible and EPR) of this isoform is typical of multicopper oxidases, but its enzymatic and physico-chemical properties proved to be markedly different from those of LAC1, the constitutive laccase previously purified from the same organism. In particular, the LAC2 kcat values observed for the oxidation of the substrates syringaldazine (kcat = 65 600 min-1), ABTS (2,2-azino-bis-[3-ethylthiazoline-6-sulfonate] (kcat = 41 000 min-1) and guaiacol (kcat = 75 680 min-1) are 10-40 times those obtained with LAC1 and the redox potential of its T1 copper is 0.17 V lower than that of LAC1 (E degrees = 0.73 V). This is the first report on a single organism producing simultaneously both a high and a low redox potential laccase. The cDNA, clac2, was cloned and sequenced. It encodes a protein of 528 amino acids that shares 69% identity (79% similarity) with LAC1 and 81% identity (95% similarity) with Lcc3-2 from Polyporus ciliatus (AF176321-1), its nearest neighbor in database. Possible reasons for why this basidiomycete produces, in vivo, enzyme forms with such different behaviors are discussed.

Reduction of Yersinia enterocolitica load in deliberately inoculated blood: the effects of blood prestorage temperature and WBC filtration.

BACKGROUND: Yersinia enterocolitica is known to cause severe infections in patients who receive transfusions. STUDY DESIGN AND METHODS: The aim of the study was to define the best strategy for reducing the bacterial load in blood that was deliberately contaminated with Y. enterocolitica by combining prestorage temperature and WBC filtration with conditions of blood processing close to those applied in blood banks. RESULTS: The effects of three prestorage temperatures (4 degrees C, 20 degrees C, 37 degrees C) were evaluated at various times after infection. The best reduction of bacterial load was achieved after 3 hours at 20 degrees C. In further experiments, conducted according to the former specifications, filtration of whole blood from eight and six donors with an inoculum of 100 and 500 to 1000 CFUs per mL, respectively, resulted in a total inhibition of bacterial growth up to 42 days after infection. After fractionation of blood components, in contrast to plasma and RBCs, filtration was shown to reduce dramatically the bacterial growth in buffy coats, demonstrating that the antibacterial effect of filtration was supported by the removal of infected WBCs from blood samples. CONCLUSION: These results provide support for the systematic use of blood filtration in the preparation of blood components to prevent Y. enterocolitica infection of patients receiving transfusions.

Obtaining cornea donation consent by telephone.

BACKGROUND: Cornea donation process comes up against difficulties in obtaining families' consent. A face-to-face interview is often not possible for logistical reasons. We carried out a prospective study of the effectiveness of telephone contact in obtaining donation consent. METHODS: Consent was obtained by a single, nonmedical, hospital coordinator. If a face-to-face interview was not possible, a telephone interview was conducted using a standardized procedure. RESULTS: Over a 21-month period, 334 families were contacted, either in a face-to-face interview (142, 42.5%) or by telephone (192, 57.5%). Donation consent was obtained in 66.5% of cases, 106 times by telephone and 116 times in face-to-face interview. The acceptance rate was 55.2% by telephone and 81.6% face to face (P<0.001). In total, 47.7% of the cornea recovery consents were obtained after telephone interview. CONCLUSIONS: Telephone interview is an effective method for obtaining consent to cornea donation. Although the acceptance rate using this method is lower than by face-to-face interview, using the telephone should not be overlooked as this enabled procurement of nearly half the corneas in our hospital.