Quantification of indicator and pathogenic bacteria in manures and digestates from three agricultural biogas plants over a one-year period.

Interest in the conversion of manure in biogas via anaerobic digestion (AD) is growing, but questions remain about the biosafety of digestates. For a period of one year, we monitored the impact of three mesophilic agricultural biogas plants (BPs) mainly fed with pig manure (BP1, BP3) or bovine manure (BP2) on the physicochemical parameters, the composition of the microbial community and the concentration of bacteria (E. coli, enterococci, Salmonella, Campylobacter, Listeria monocytogenes, Clostridium perfringens, Clostridium botulinum and Clostridioides difficile).

Occurrence and Diversity of Listeria monocytogenes Isolated from Two Pig Manure Treatment Plants in France.

The presence of Listeria monocytogenes in piggery effluents intended for irrigation crops may be a source of bacterial dissemination in agriculture. The occurrence and diversity of L. monocytogenes in the farm environment were examined in two pig manure treatment systems (S1 and S2).

Impact of mesophilic anaerobic digestion and post-treatment of digestates on the transfer of conjugative antimicrobial resistance plasmids.

Manure is a major source of antimicrobial-resistant bacteria and resistance genes carried by mobile genetic elements such as plasmids. In France, the number of on-farm biogas plants has increased significantly in recent years. Our study investigated the impact of mesophilic anaerobic digestion (AD) and the post-treatment of digestates on the fate of conjugative plasmids, along with their potential transfer of antimicrobial resistance.

Characterization of Isolates Collected from Three Agricultural Biogas Plants over a One-Year Period.

Digestate produced by agricultural biogas plants (BGPs) may contain pathogenic bacteria. Among them, deserves particular attention due to its ability to grow under anaerobic conditions and persist in amended soil. The aim of this study was to examine the potential pathogenicity and the antimicrobial resistance of in manure and digestate collected from three agricultural biogas plants (BGPs).

Characterization of Clostridioides difficile strains isolated from manure and digestate in five agricultural biogas plants.

Clostridioides difficile strains were isolated from manure and digestate samples from five biogas plants in France. The objective of this study was to characterize these isolates using PCR ribotyping, wgMLST, a multiplex PCR targeting genes encoding for the main virulence factors, i.e.

Evaluation of the occurrence of sporulating and nonsporulating pathogenic bacteria in manure and in digestate of five agricultural biogas plants.

The number of agricultural biogas plants has been increasing in the past decades in some European countries. Digestates obtained after anaerobic digestion (AD) of manure are usually spread on agricultural land; however, their hygiene status regarding pathogens posing public health and/or animal health challenges has been poorly characterized up to now in France. In this study, three replicates of manure and digestate were collected from five farm biogas plants receiving animal manure in order to assess the occurrence and concentrations of sporulating (Clostridium botulinum, Clostridioides difficile, Clostridium perfringens) and nonsporulating (Listeria monocytogenes, thermotolerant Campylobacter spp.

Fate of two strains of extended-spectrum beta-lactamase producing Escherichia coli in constructed wetland microcosm sediments: survival and change in antibiotic resistance profiles.

Free water surface constructed wetlands (FWS CW) are efficient technologies to limit the transfer of antibiotic resistant bacteria (ARB) originating from urban effluents into the aquatic environment. However, the decrease in ARB from inflow to outflow through the FWS CW may be explained by their transfer from the water body to the sediment. To investigate the behavior of ARB in the sediment of a FWS CW, we inoculated three microcosms with two strains of extended-spectrum beta-lactamase producing Escherichia coli (ESBL E.

Transcriptomic Analysis of the Adaptation of to Lagoon and Soil Matrices Associated with a Piggery Environment: Comparison of Expression Profiles.

Understanding how , the causative agent of listeriosis, adapts to the environment is crucial. Adaptation to new matrices requires regulation of gene expression. To determine how the pathogen adapts to lagoon effluent and soil, two matrices where has been isolated, we compared the transcriptomes of CIP 110868 20 min and 24 h after its transfer to effluent and soil extract.

Impact of wet aerobic pretreatments on cellulose accessibility and bacterial communities in rape straw.

A new pretreatment method of lignocellulosic biomass was explored by using a wet aerobic process with an alkaline lignin and a mineral salt solution. This treatment significantly improved structural modification of rape straw used as substrate model in this study. Change in cellulose accessibility to cellulase of rape straw rose up to six fold within the first days of this pretreatment without generated significant modification of van Soest lignocellulose fractionation.

Characterisation of the biodegradability of post-treated digestates via the chemical accessibility and complexity of organic matter.

The stability of digestate organic matter is a key parameter for its use in agriculture. Here, the organic matter stability was compared between 14 post-treated digestates and the relationship between organic matter complexity and biodegradability was highlighted. Respirometric activity and CH yields in batch tests showed a positive linear correlation between both types of biodegradability (R=0.

Cellulose accessibility and microbial community in solid state anaerobic digestion of rape straw.

Solid state anaerobic digestion (SSAD) with leachate recirculation is an appropriate method for the valorization of agriculture residues. Rape straw is a massively produced residue with considerable biochemical methane potential, but its degradation in SSAD remains poorly understood. A thorough study was conducted to understand the performance of rape straw as feedstock for laboratory solid state anaerobic digesters.

Persistence and Potential Viable but Non-culturable State of Pathogenic Bacteria during Storage of Digestates from Agricultural Biogas Plants.

Despite the development of on-farm anaerobic digestion as a process for making profitable use of animal by-products, factors leading to the inactivation of pathogenic bacteria during storage of digestates remain poorly described. Here, a microcosm approach was used to evaluate the persistence of three pathogenic bacteria ( Derby, and ) in digestates from farms, stored for later land spreading. Nine samples, including raw digestates, liquid fractions of digestate and composted digestates, were inoculated with each pathogen and maintained for 40 days at 24°C.

Class P dye-decolorizing peroxidase gene: Degenerated primers design and phylogenetic analysis.

Dye-decolorizing peroxidases (DyPs) were classified as a new family of heme peroxidase in 2007. Produced by various bacteria, they are the first bacterial enzymes known able to degrade lignin and dyes, for which their application in waste treatment and pretreatment of lignocellulosic biomass could be envisaged. In this work, a PCR primer pair was created and tested that enabled the detection and quantification of a wide range of bacterial genes of P class DyP in complex matrices.

Free water surface constructed wetlands limit the dissemination of extended-spectrum beta-lactamase producing Escherichia coli in the natural environment.

The fates of Escherichia coli and extended-spectrum beta-lactamase-producing E. coli (ESBL E. coli) were studied over a period of one year in a free water surface constructed wetland (FWS CW) with a succession of open water zones and vegetation ponds (Typha or Phragmites), that received the effluent from a wastewater treatment plant.

Isolation of bacterial strains able to metabolize lignin and lignin-related compounds.

Unlabelled: In this study, we identified five strains isolated from soil and sediments able to degrade kraft lignin, aromatic dyes and lignin derivatives. Using 16S rRNA gene sequencing, the isolates were identified as Serratia sp. JHT01, Serratia liquefacien PT01, Pseudomonas chlororaphis PT02, Stenotrophomonas maltophilia PT03 and Mesorhizobium sp.

Fate of Viable but Non-culturable Listeria monocytogenes in Pig Manure Microcosms.

The fate of two strains of Listeria monocytogenes and their ability to become viable but non-culturable (VBNC) was investigated in microcosms containing piggery effluents (two raw manures and two biologically treated manures) stored for 2 months at 8 and 20°C. Levels of L. monocytogenes were estimated using the culture method, qPCR, and propidium monoazide treatment combined with qPCR (qPCRPMA).

Experimental design for the optimization of propidium monoazide treatment to quantify viable and non-viable bacteria in piggery effluents.

Background: Distinguishing between viable and dead bacteria in animal and urban effluents is a major challenge. Among existing methods, propidium monoazide (PMA)-qPCR is a promising way to quantify viable cells. However, its efficiency depends on the composition of the effluent, particularly on total suspended solids (TSS)) and on methodological parameters.

Control of nitrogen behaviour by phosphate concentration during microalgal-bacterial cultivation using digestate.

The cultivation of microalgae with digestate supernatant is a promising process for the recovery of mineralized nutrients (P, N) from anaerobic digestion. Nevertheless, the variability of phosphorus concentration in the influent could limit this process. The impact of initial N:P ratios between 3 and 76gNgP(-1) was studied and proved no growth limitation over 14-day batch experiments even when P was depleted.

Occurrence of lignin degradation genotypes and phenotypes among prokaryotes.

A number of prokaryotes actively contribute to lignin degradation in nature and their activity could be of interest for many applications including the production of biogas/biofuel from lignocellulosic biomass and biopulping. This review compares the reliability and efficiency of the culture-dependent screening methods currently used for the isolation of ligninolytic prokaryotes. Isolated prokaryotes exhibiting lignin-degrading potential are presented according to their phylogenetic groups.

Digestate color and light intensity affect nutrient removal and competition phenomena in a microalgal-bacterial ecosystem.

During anaerobic digestion, nutrients are mineralized and may require post-treatment for optimum valorization. The cultivation of autotrophic microalgae using the digestate supernatant is a promising solution; however the dark color of the influent poses a serious problem. First, the color of the digestates was studied and the results obtained using three different digestates demonstrated a strong heterogeneity although their color remained rather constant over time.

Comparison of DNA extraction kits and modification of DNA elution procedure for the quantitation of subdominant bacteria from piggery effluents with real-time PCR.

Four commercial DNA extraction kits and a minor modification in the DNA elution procedure were evaluated for the quantitation of bacteria in pig manure samples. The PowerSoil(®), PowerFecal(®), NucleoSpin(®) Soil kits and QIAamp(®) DNA Stool Mini kit were tested on raw manure samples and on lagoon effluents for their ability to quantify total bacteria and a subdominant bacteria specific of pig manure contamination: Lactobacillus amylovorus. The NucleoSpin(®) Soil kit (NS kit), and to a lesser extent the PowerFecal(®) kit were the most efficient methods.

Effect of land application of manure from enrofloxacin-treated chickens on ciprofloxacin resistance of Enterobacteriaceae in soil.

A field plot experiment was carried out to evaluate the impact of spreading chicken manure containing enrofloxacin (ENR) and its metabolite ciprofloxacin (CIP), on the levels of CIP-resistant Enterobacteriaceae in soil. The manures from chickens treated with ENR and from untreated control chickens were applied on six plots. Total and CIP-resistant Enterobacteriaceae were counted on Violet Red Bile Glucose medium containing 0 to 16mg L(-1) of CIP.

The impact of fouling on the process performance of the thermal treatment of pig slurry using tubular heat exchangers.

The aim of this study was to determine the kinetics of fouling and their influence on the performance of a thermal treatment process used for sanitisation of pig slurry. Two temperatures (55 °C and 80 °C) were investigated. One trial was carried out at 55 °C and 80 °C in which the slurry was not re-circulated and one trial at 80 °C in which 100% or 50% of the slurry was re-circulated.