Search results for "Biodegradation"
showing 10 items of 317 documents
Insights into the biological process performance and microbial diversity during thermophilic microalgae co-digestion in an anaerobic membrane bioreac…
2020
Abstract Harvested microalgae Chlorella spp. and primary sludge were co-digested in a laboratory-scale anaerobic membrane bioreactor (AnMBR) under thermophilic conditions (55 °C). The system was run for 700 days divided into four experimental phases to determine the influence of the organic loading rate on the process performance and the microbial community. The rise in organic loading rate from 0.17 to 0.5 gCOD·L−1·d−1 led to a 35% improvement in methane production. The system reached 69% biodegradability working at 0.5 gCOD·L−1·d−1 and a high solids retention time (70 d), indicating the efficient conversion of biomass into biogas through the AnMBR configuration while avoiding possible inh…
Effect of a co-substrate supply in a MBR treating shipboard slop: Analysis of hydrocarbon removal, biomass activity and membrane fouling tendency
2018
The paper reports the main results of an experiment carried out on a membrane bioreactor (MBR) plant designed for the treatment of shipboard slops. With a view of a co-treatment process of the slop with other wastewaters, sodium acetate, as external co-substrate, was supplied (high dosage – Period 1, low dosage – Period 2) to evaluate its effects on hydrocarbons removal. The MBR pilot plant enabled approximately 99% of total petroleum hydrocarbon (TPH) removal during the entire experiment, confirming the robustness of the MBR technology for the treatment of slops. The chromatography/mass spectrometry analysis showed that the removal efficiency for each alkane was close to the value observed…
Polyethylene bio-degradation by caterpillars?
2017
In their recent paper on the degradation of polyethylene by caterpillars of the wax moth Galleria melonella, Bombelli et al.[1] report various experiments, including microscopic and spectroscopic data which the authors believe support the chemical digestion of the polymers by these insects. While the biodegradation of mostly inert artificial polymers is definitely a very interesting research field, we must respectfully disagree with the methodology and conclusions from this paper.
Monod-based ‘single-data’ strategy for biodegradation screening tests
2020
Environmental contextObtaining biodegradation data over time can be difficult, especially when dealing with environmental compartments of increasing complexity. We evaluated the possibility of obtaining a full biodegradation depletion curve from a single biodegradation-time experimental measurement, and found that environmental information related to potential chemical persistence can be derived. The applicability of this ‘single-data’ strategy is illustrated using simulated and experimental data for several compounds. AbstractInformation obtained from biodegradability tests, e.g. half-life (t50) or kinetics parameters, is relevant in environmental risk assessment of new chemicals. In thes…
Evidence for 2,4-D mineralisation in Mediterranean soils: impact of moisture content and temperature
2009
BACKGROUND: The 2,4-D degradation ability of the microbiota of three arable Mediterranean soils was estimated. The impact of soil moisture and temperature on 2,4-D degradation was investigated. RESULTS: The microbiota of the three soils regularly exposed to 2,4-D were able rapidly to mineralise this herbicide. The half-life of 2,4-D ranged from 8 to 30 days, and maximum mineralisation of 14C-2,4-D ranged from 57 to 71%. Extractable 14C-2,4-D and 14C-bound residues accounted for less than 1 and 15% respectively of the 14C-2,4-D initially added. The highest amounts of 14C-2,4-D bound residues were recorded in the soil with the lowest 2,4-D-mineralising ability. Although all three soils were a…
Green Composites Based on PLA and Agricultural or Marine Waste Prepared by FDM
2021
Three dimensional-printability of green composites is recently growing in importance and interest, especially in the view of feasibility to valorize agricultural and marine waste to attain green fillers capable of reducing bioplastic costs, without compromising their processability and performance from an environmental and mechanical standpoint. In this work, two lignocellulosic fillers, obtained from Opuntia ficus indica and Posidonia oceanica, were added to PLA and processed by FDM. Among the 3D printed biocomposites investigated, slight differences could be found in terms of PLA molecular weight and filler aspect ratio. It was shown that it is possible to replace up to 20% of bioplastic …
Genome and phenotype microarray analyses of rhodococcus sp. BCP1 and rhodococcus opacus R7: Genetic determinants and metabolic abilities with environ…
2015
In this paper comparative genome and phenotype microarray analyses of Rhodococcus sp. BCP1 and Rhodococcus opacus R7 were performed. Rhodococcus sp. BCP1 was selected for its ability to grow on short-chain n-alkanes and R. opacus R7 was isolated for its ability to grow on naphthalene and on o-xylene. Results of genome comparison, includ- ing BCP1, R7, along with other Rhodococcus reference strains, showed that at least 30% of the genome of each strain presented unique sequences and only 50% of the predicted proteome was shared. To associate genomic features with metabolic capabilities of BCP1 and R7 strains, hundreds of different growth conditions were tested through Phenotype Microarray, b…
Combined metabolic activity within an atrazine-mineralizing community enriched from agrochemical factory soil
2007
Abstract The main objective of this work was to characterize an atrazine-mineralizing community originating from agrochemical factory soil, especially to elucidate the catabolic pathway and individual metabolic and genetic potentials of culturable members. A stable four-member bacterial community, characterized by colony morphology and 16S rDNA sequencing, was rapidly able to mineralize atrazine to CO 2 and NH 3 . Two primary organisms were identified as Arthrobacter species (ATZ1 and ATZ2) and two secondary organisms (CA1 and CA2) belonged to the genera Ochrobactrum and Pseudomonas, respectively. PCR assessment of atrazine-degrading genetic potential of the community, revealed the presence…
Durability of Biodegradable Polymer Nanocomposites
2021
Biodegradable polymers (BP) are often regarded as the materials of the future, which address the rising environmental concerns. The advancement of biorefineries and sustainable technologies has yielded various BP with excellent properties comparable to commodity plastics. Water resistance, high dimensional stability, processability and excellent physicochemical properties limit the reviewed materials to biodegradable polyesters and modified compositions of starch and cellulose, both known for their abundance and relatively low price. The addition of different nanofillers and preparation of polymer nanocomposites can effectively improve BP with controlled functional properties and change the…
Metabolic shift of polyphosphate-accumulating organisms with different levels of polyphosphate storage
2012
Previous studies have shown that polyphosphate-accumulating organisms (PAOs) are able to behave as glycogen-accumulating organisms (GAOs) under different conditions. In this study we investigated the behavior of a culture enriched with Accumulibacter at different levels of polyphosphate (poly-P) storage. The results of stoichiometric ratios Gly degraded/HAc uptake, PHB synthesized/HAc uptake, PHV synthesized/HAc uptake and P release/HAc uptake confirmed a metabolic shift from PAO metabolism to GAO metabolism: PAOs with high poly-P content used the poly-P to obtain adenosine tri-phosphate (ATP), and glycogen (Gly) to obtain nicotinamide adenine dinucleotide (NADH) and some ATP. In a test whe…