Bio-physical pre-treatments in anaerobic digestion of organic fraction of municipal solid waste to optimize biogas production and digestate quality for agricultural use.

This study optimized the anaerobic digestion (AD) of separated collected organic fractions of municipal solid waste (OFMSW) to produce energy and digestate as biofertilizer. Due to OFMSW's partial recalcitrance to degradation, enzymatic (UPP2, MCPS, USC4, USE2, A. niger) and physical (mechanical blending, heating, hydrodynamic cavitation) pre-treatments were tested. Experimental and modeling approaches were used to compare AD performance regarding energy sustainability and digestate quality. Digestate was separated into solid and liquid fractions, and then chemically and physically characterized by investigating the nutrient release mechanisms. Principal Component Analysis was applied, equally weighing energy and digestate productions. Unlike previous studies focusing only on biogas, this study evaluated the effects of pre-treatments on both biogas and digestate production, viewing AD as a biorefinery process for urban waste valorization. Results showed that all pre-treatments were energetically sustainable, but enzymatic pre-treatments yielded digestates richer in nutrients (increase of 80% N, 200% P and 150% K as compared to OFMSW) and with greater organic matter degradation compared to physical pre-treatments. The liquid fraction of digestate from enzymatic pre-treatments had higher nutrient concentrations, while those from physical pre-treatments had more balanced nutrient content, making them more suitable for fertigation.

Natural protein-polysaccharide-phenol complex particles from rice bran as novel food-grade Pickering emulsion stabilizers.

To develop novel food-grade Pickering emulsion stabilizers, insoluble rice bran protein-polysaccharide-phenol natural complex (IRBPPP) was prepared into Pickering emulsion stabilizers after different mechanical pretreatments (shear, high-pressure homogenization, ultrasonic, and combined mechanical pretreatment). With the increase in mechanical pretreatment types, the covalent binding of proteins and polysaccharides in IRBPPP gradually enhanced, the breakage efficiency of IRBPPP gradually increased (IRBPPP particle size decreased from 220.54 to 67.89 µm, the specific surface area of IRBPPP particle increased from 993.47 to 2033.86 cm-1/g), and the microstructure of IRBPPP gradually showed an orderly network structure, which enhanced the IRBPPP dispersion stability and the Pickering emulsion stability. Pickering emulsion stability was highly correlated (P < 0.01) with the breakage efficiency of IRBPPP particles. Overall, the combined mechanical pretreatment improved the stability of the IRBPPP-stabilized Pickering emulsion. The study added value to rice bran products and offered a new way to create stable food-grade Pickering emulsions for functional foods using natural protein-polysaccharide-phenol complex particles.

Recrystallization of Cellulose, Chitin and Starch in Their Individual and Native Forms.

Semi-crystalline natural polymers are involved in many technological processes. Biopolymers having identical chemical compositions can differ in reactivity in heterogeneous transformations depending on their crystal structure (polymorphic modification). This paper compares the crystal structure recrystallization processes occurring in natural polysaccharides (cellulose, chitin, and starch) in the individual form and as a component of native biomass. Aqueous treatment of pre-amorphized semi-crystalline biopolymers was shown to result in swelling, thus alleviating the kinetic restrictions imposed on the restoration of crystalline regions and phase transition to the thermodynamically more stable polymorphic modification. During recrystallization, cellulose I in the individual form and within plant-based biomass undergoes a transition to the more stable cellulose II. A similar situation was demonstrated for α- and ß-chitin, which recrystallize only into the α-polymorphic modification in the case of both individual polymers and native materials. Recrystallization of A-, B-, and C-type starch, both in the individual form and within plant-based flour, during aqueous treatment, results in a phase transition, predominantly to the B-type starch. The recrystallization process depends on the temperature of aqueous treatment; longer treatment duration has almost no effect on the recrystallization degree of polymers, both in the individual form and within native materials.

Physical pretreatment of three biowastes to improve black soldier fly larvae bioconversion efficiency.

Black soldier fly larvae (BSFL, Hermetia illucens (L.)) are recognized for efficient biowaste reduction while yielding valuable proteins and fats for animals. However, lignocellulosic fibers in biowastes are difficult to digest by biowaste and larval digestive tract microorganisms as well as the larvae themselves. This study investigated two biowaste physical pretreatments (thermal, mechanical) for improving BSFL processing of fibrous biowastes. Cow manure, spent grain, and grass clippings were thermally pretreated at 90 °C for three durations (0.5, 1 and 4 h). Contrary to expectations, thermal pretreatment resulted in either no improvement or decreased larval performance on all substrates, regardless of treatment duration. In contrast, mechanical pretreatment of spent grain and grass clippings, involving milling with three screen sizes (0.5, 1 and 2 mm) showed promising results. Specifically, bioconversion rates on 0.5 mm-milled spent grain and grass clippings increased by 0-53 % and 25-44 % dry mass, respectively compared to untreated. Additionally, larval protein conversion increased by 41 % and 23 % on spent grain and grass clippings, respectively. However, mechanical pretreatment did not affect fiber degradation by larval conversion, as hemicellulose decreased by 25 % and 75 % for spent grain and grass clippings, respectively, regardless of particle size. Particle size reduction influenced substrate microbial respiration (CO2 mg/min), with 0.5-mm milled grass clippings exhibiting higher respiration compared to untreated, although this effect was not observed for spent grain. This study highlights mechanical pretreatment's potential in enhancing BSFL bioconversion of fibrous biowastes and the importance of understanding substrate physical properties influencing substrate microorganisms and BSFL.

Mechanical pretreatment of typical agricultural biomass on shape characterization and NO emissions during combustion.

The impact of mechanical pretreatment of corn straw (CS), pea straw (PS), and wheat straw (WS), on shape characterization and NO emissions during combustion were investigated in this research. Particle size ranges were obtained and characterized their shape factors using Image J correction. The thermal properties and NO emissions of the different-sized particles were investigated by TG-MS and fixed-bed reactor. Compared with CS and PS, WS is more likely to break into smaller particles due to its moderate strength. Amine-N completely disappeared after pyrolysis, whereas pyrrolic-N and pyridinic-N were the main N functionalities in char-N. During the volatile burning stage, the maximum peak of NO concentration was 270, 354 and 311 ppm for CS, PS and WS, respectively. NO was detected at a steady level during the semicoke combustion stage, and the duration increased with particle size. The NO concentration decreased sharply in a short duration during the fixed carbon combustion stage.

Life cycle assessment of the hydrothermal carbonization process applied to the wet fraction mechanically separated from municipal mixed waste.

The under-sieve fraction (USF), obtained as one of the output streams from the mechanical pretreatment of mixed municipal solid waste, is usually aerobically biologically stabilized before being landfilled. For its characteristics (i.e., moisture and organic content), the USF can be alternatively processed by hydrothermal carbonization (HTC), producing hydrochar to be used for energy production. Based on previous results obtained from laboratory HTC tests of the USF, this work is aimed at evaluating the sustainability of the proposed process from an environmental point of view by applying the Life Cycle Assessment. Various combinations of process parameters (temperature, time, and dry solid-to-water ratios) and two different utilization pathways for hydrochar (the whole amount produced in external lignite power plants or part of it used internally) are compared. The results indicate that environmental performances are mainly connected with process energy consumption: in general, the cases operating at the lowest dilution ratio and the highest temperature provide improved environmental indicators. Co-combusting all the produced hydrochar in external power plants provides better environmental performances than feeding a portion of it to the HTC itself: the avoided effects by displacing lignite are higher than the additional burdens from natural gas use. Then, alternative process water treatments are compared, showing that the burdens added by the process water treatments do not offset the benefits generated by the main HTC process for the major part of the considered environmental indicators. Finally, the proposed process indicates better environmental performances when compared to the conventional method of treating the USF, based on aerobic biostabilization and landfilling.

Production of Designer Xylose-Acetic Acid Enriched Hydrolysate from Bioenergy Sorghum, Oilcane, and Energycane Bagasses.

Xylan accounts for up to 40% of the structural carbohydrates in lignocellulosic feedstocks. Along with xylan, acetic acid in sources of hemicellulose can be recovered and marketed as a commodity chemical. Through vibrant bioprocessing innovations, converting xylose and acetic acid into high-value bioproducts via microbial cultures improves the feasibility of lignocellulosic biorefineries. Enzymatic hydrolysis using xylanase supplemented with acetylxylan esterase (AXE) was applied to prepare xylose-acetic acid enriched hydrolysates from bioenergy sorghum, oilcane, or energycane using sequential hydrothermal-mechanical pretreatment. Various biomass solids contents (15 to 25%, w/v) and xylanase loadings (140 to 280 FXU/g biomass) were tested to maximize xylose and acetic acid titers. The xylose and acetic acid yields were significantly improved by supplementing with AXE. The optimal yields of xylose and acetic acid were 92.29% and 62.26% obtained from hydrolyzing energycane and oilcane at 25% and 15% w/v biomass solids using 280 FXU xylanase/g biomass and AXE, respectively.

Hydrodynamic disintegration of thickened excess sludge and maize silage to intensify methane production: Energy effect and impact on microbial communities.

The aim of this project was to study the combination of two methods to increase methane production: feedstock pretreatment by hydrodynamic disintegration and co-digestion of maize silage (MS) with thickened excess sludge (TES). Disintegration of TES alone resulted in a 15% increase in specific methane production from 0.192 Nml/gVS (TES + MS) to 0.220 Nml/gVS (pretreated TES + MS). The energy balance revealed additional energy (0.14 Wh) would cover only the energy expenditure for the mechanical pretreatment and would not allow for net energy profit. Identification of the methanogenic consortia by 16S rRNA gene amplicon sequencing revealed that Chloroflexi, Bacteroidota, Firmicutes, Proteobacteria and Actinobacteriota were five most abundant bacteria phyla, with Methanothrix and Methanolinea as the dominant methanogens. Principal component analysis did not show any effect of feedstock pretreatment on methanogenic consortia. Instead, the composition of inoculum was the decisive factor in shaping the microbial community structure.

Can Biomass Mastication Assist the Downstreaming of Polyhydroxyalkanoates Produced from Mixed Microbial Cultures?

Polyhydroxyalkanoates (PHAs) are natural polyesters which biodegrade in soils and oceans but have more than double the cost of comparable oil-based polymers. PHA downstreaming from its biomass represents 50% of its overall cost. Here, in an attempt to assist downstreaming, mastication of wet biomasses is tested as a new mechanical continuous biomass pretreatment with potential for industrial upscaling. Downstreaming conditions where both product recovery and purity are low due to the large amount of treated wet biomass (50% water) were targeted with the following process: extraction of 20 g in 100 mL solvent at 30 °C for 2 h, followed by 4.8 h digestion of 20 g in 0.3 M NaOH. Under the studied conditions, NaOH digestion was more effective than solvent extraction in recovering larger PHA amounts, but with less purity. A nearly 50% loss of PHA was seen during digestion after mastication. PHAs downstreamed by digestion with large amounts of impurities started to degrade at lower temperatures, but their melt elasticity was thermally stable at 170 °C. As such, these materials are attractive as fully PHA-compatible processing aids, reinforcing fillers or viscosity modifiers. On the other hand, wet biomass mastication before solvent extraction improves PHA purity and thermal stability as well as the melt rheology, which recovers the viscoelasticity measured with a PHA extracted from a dried biomass.

Turning an invasive alien species into a valuable biomass: Anaerobic digestion of Rugulopteryx okamurae after thermal and new developed low-cost mechanical pretreatments.

The invasive alien seaweed Rugulopteryx okamurae (R.o.) has spread quickly through the Mediterranean Sea causing an unprecedented ecological impact. A solution integrated into a circular economy model is needed in order to curb the negative effects of its presence. Anaerobic digestion (AD) is proposed as a feasible process able to transform biomass into renewable energy. Nevertheless, in order to improve the methane yield and surpass the drawbacks associated with AD processes, this research proposes a thermal pretreatment and a new developed method where the macroalgae is mechanically pretreated with zeolite. Chemical and microstructure characterization of the algal biomass after pretreatments involved scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). The highest methane yields of 240 (28) and 250 (20) NLCH4 kg-1 VSadded were obtained with the new mechanical pretreatment and the thermal pretreatment at 120 °C for 45 min without zeolite, achieving a 35 % improvement against the non-pretreated algae. A direct relationship between the crystallinity index of the samples and methane production was observed. The experimental data of methane production versus time were found to be in accordance with both first-order kinetic and Transference Function mathematical models.

Laser Direct Joining of Steel to Polymethylmethacrylate: The Influence of Process Parameters and Surface Mechanical Pre-Treatment on the Joint Strength and Quality.

The search for lightweight structures increases the demand for non-metallic materials, such as polymers, composites, and hybrid structures. This work presents the dissimilar joining through direct laser joining between polymethylmethacrylate (PMMA) and S235 galvanised steel using a pulsed Nd:YAG laser. The main goal is to determine the influence of processing parameters on joint strength and quality. In addition, the impact of surface conditions on the joint quality was also analysed. Overall, the optimum ranges of process parameters were found, and some are worth highlighting, such as the laser beam diameter and pulse duration, which significantly influenced the joint strength. Failure of the welded samples occurred in PMMA component, demonstrating good joint efficiency. Additionally, a maximum increase of 5.1% of the tensile shear strength was achieved thanks to the mechanical pre-treatment. It is possible to conclude that the joining between PMMA and the S235 galvanised steel can be performed by optimising the process parameters. Additionally, it can be enhanced through surface pre-treatments by exploring the mechanical interlock between both materials.

Performance Evaluation of Combined Hydrothermal-Mechanical Pretreatment of Lignocellulosic Biomass for Enzymatic Enhancement.

Pretreatment is a crucial process in a lignocellulosic biorefinery. Corncob is typically considered as a natural renewable carbon source to produce various bio-based products. This study aimed to evaluate the performance of the hydrothermal-mechanical pretreatment of corncob for biofuels and biochemical production. Corncob was first pretreated by liquid hot water (LHW) at different temperatures (140-180 °C) and duration (30, 60 min) and then subjected to centrifugal milling to produce bio-powders. To evaluate the performance of this combined pretreatment, the energy efficiency and waste generation were investigated. The results indicated that the maximum fermentable sugars (FS) were 0.488 g/g biomass obtained by LHW at 180 °C, 30 min. In order to evaluate the performance of this combined pretreatment, the energy efficiency and waste generation were 28.3 g of FS/kWh and 7.21 kg of waste/kg FS, respectively. These obtained results indicate that the combined hydrothermal-mechanical pretreatment was an effective pretreatment process to provide high energy efficiency and low waste generation to produce biofuels. In addition, the energy efficiency and waste generation will be useful indicators for process scaling-up into the industrial scale. This combined pretreatment could be a promising pretreatment technology for the production of biofuels and biochemicals from lignocellulosic valorization.

Gravity and Electrostatic Separation for Recovering Metals from Obsolete Printed Circuit Board.

This study proposed an evaluation of enrichment processes of obsolete Printed Circuit Boards (PCBs), by means of gravity and electrostatic separation, aiming at the recovery of metals. PCBs are the most important component in electronic devices, having high concentrations of metals and offering a secondary source of raw materials. Its recycling promotes the reduction in the environmental impacts associated with its production, use, and disposal. The recovery method studied started with the dismantling of the PCB, followed by a comminution and granulometric classification. Subsequent magnetic, gravity, and electrostatic separations were performed. After the separations, a macroscopic visual evaluation and chemical analysis were carried out, determining the metal content in the concentrate products. The results obtained from gravity separation showed a product with metallic concentrations of 89% and 76% for particle sizes of 0.3−0.6 mm and 0.6−1.18 mm, respectively. In electrostatic separation, the product obtained was 88% for the lower particle size (<0.3 mm) and 62% for particles sizes >1.18 mm.

Impact of mechanical and thermo-chemical pretreatments to enhance anaerobic digestion of poly(lactic acid).

To date, the introduction of biodegradable plastics such as PLA in anaerobic digestion systems has been limited by a very low rate of biodegradation. To overcome these limitations, pretreatment technologies can be applied. In this study, the impact of pretreatments (mechanical, thermal, thermo-acid, and thermo-alkaline) was investigated. Mechanical pretreatment of PLA improved its biodegradation rate but did not affect the ultimate methane potential (430-461 NL CH4 kg-1 VS). In parallel, thermal and thermo-acid pretreatments exhibited a similar trend for PLA solubilization. Both of these pretreatments only achieved substantial solubilization (>60%) at higher temperatures (120 and 150 °C). At lower temperatures (70 and 90 °C), negligible solubilization (between 1 and 6%) occurred after 48 h. By contrast, coupling of thermal and alkaline pretreatment significantly increased solubilization at the lower temperatures (70 and 90 °C). In terms of biodegradation, thermo-alkaline pretreatment (with 5% w/v Ca(OH)2) of PLA resulted in a similar methane potential (from 325 to 390 NL CH4 kg-1 VS) for 1 h at 150 °C, 6 h at 120 °C, 24 h at 90 °C, and 48 h at 70 °C. Reduction of the Ca(OH)2 concentration (from 5% to 0.5% w/v) highlighted that a concentration of 2.5% w/v was sufficient to achieve a substantial level of biodegradation. Pretreatment at 70 and 90 °C using 2.5% w/v Ca(OH)2 for 48 h resulted in biodegradation yields of 73% and 68%, respectively. Finally, a good correlation (R2 = 0.90) was found between the PLA solubilization and its biodegradation.

Influence of mechanical operation on the biodelignification of Leucaena leucocephala by xylanase treatment.

This study aimed at energy reduction during pulping of L. leucocephala by passing the wood chips through an impressafiner followed by xylanase pretreatment. An impressafiner compressed the chips and converted them into spongy materials. Wood chips of L. leucocephala with or without de-structuring and de-structured wood chips followed by enzymatic treatment were subjected to Kraft pulping at different temperatures varying from 135 to 170 °C and active alkali varying from 12 to 20% (as Na2O) to observe effect on screened pulp yield and kappa number. The de-structured wood chips followed by enzymatic treatment produced a pulp yield of 48.2% and kappa number 18.6. L. leucocephala without de-structuring produced a pulp yield of 50.1% and kappa number 23.7. When the pulp was subjected to oxygen delignification to reduce kappa number in the vicinity of 18.6, pulp showed shrinkage by 6.64% compared to Kraft pulp of de-structured wood chips followed by enzymatic treatment. Kraft pulp produced from de-structured wood chips of L. leucocephala followed by enzymatic treatment showed net saving of US$ 163.15 per digester over Kraft pulp produced without de-structuring of wood chips of L. leucocephala. Moreover, the pulp obtained by de-structuring followed by enzymatic treatment showed improvement in pulp brightness and physical strength properties including tensile, tear, and burst index significantly compared to pulp obtained without de-structuring.

Residual municipal solid waste as co-substrate at wastewater treatment plants: An assessment of methane yield, dewatering potential and microbial diversity.

Separately collected organic fraction of municipal solid waste, also known as biowaste, is typically used to fill the available capacity of digesters at wastewater treatment plants. However, this approach might impair the use of the ensuing digestate for fertilizer production due to the presence of sewage sludge, a contaminated substrate. Worldwide, unsorted municipal solid household waste, i.e. residual waste, is still typically disposed of in landfills or incinerated, despite its high content of biodegradables and recyclables. Once efficiently separated from residual waste by mechanical processes, the biodegradables might be appropriate to substitute biowaste at wastewater treatment plants. Thus, the biowaste would be available for fertilizer production and contribute to a reduction in the demand on non-renewable fertilizers. This study aimed at determining the technical feasibility of co-digesting the mechanically separated organic fraction of residual waste with sewage sludge. Further, key parameters for the implementation of co-digestion at wastewater treatment plants were determined, namely, degradation of the solids and organics, specific methane production, flocculant demand, and dewatered sludge production. The microbial community and diversity in both mono- and co-digestion was also investigated. Semi-continuous laboratory scale experiments showed that the co-substrate derived from the residual waste provided a stable anaerobic co-digestion process, producing 206 to 245 L of methane per kg of volatiles solids added to the digester. The dewaterability of the digestate increased by 4.8 percentage points when the co-substrate was added; however, there was also an increase in the flocculant demand. The specific dewatered sludge production was 955 kg per ton of total solids of co-substrate added to the digester. Amplicon sequencing analysis provided a detailed insight into the microbial communities, which were primarily affected by the addition of co-substrate. The microbiota was fully functional and no inhibition or problems in the anaerobic digestion process were observed after co-substrate addition.

Combination of hydrothermal and chemi-mechanical pretreatments to enhance enzymatic hydrolysis of poplar branches and insights on cellulase adsorption.

An integration of different pretreatments is important to overcome recalcitrance and realize efficient bioconversion of lignocellulosic biomass. This study aims at the effects of combination of hydrothermal pretreatment and different chemi-mechanical pretreatments on enzymatic hydrolysis, and understanding the enzymes adsorption mechanism. The combination of hydrothermal and chemi-mechanical pretreatments effectively improved the enzymatic hydrolysis of poplar substrates, in which the enzymatic hydrolysis of substrates pretreated by hydrothermal pretreatment + Fenton pretreatment + mechanical refining (HFM) was the highest (92.39% of glucose conversion yield, and 20.88 g/L of glucose concentration). The substrates' main characteristics were obviously changed after combined pretreatments, such as swelling ability and specific surface area of substrates were increased. The Langmuir adsorption model (R2 > 0.98) and pseudo second-order adsorption kinetic model (R2≈1) were well suitable to describe the adsorption of enzymes on substrates, meanwhile the adsorption mechanism was summarized.

Pyrolysis Kinetic Behaviour of Glass Fibre-Reinforced Epoxy Resin Composites Using Linear and Nonlinear Isoconversional Methods.

Due to the increasing demand for glass fibre-reinforced epoxy resin composites (GFRC), huge amounts of GFRC waste are produced annually in different sizes and shapes, which may affect its thermal and chemical decomposition using pyrolysis technology. In this context, this research aims to study the effect of mechanical pre-treatment on the pyrolysis behaviour of GFRC and its pyrolysis kinetic. The experiments were started with the fabrication of GFRC panels using the vacuum-assisted resin transfer method followed by crushing the prepared panels using ball milling, thus preparing the milled GFRC with uniform shape and size. The elemental, proximate, and morphology properties of the panels and milled GFRC were studied. The thermal and chemical decomposition of the milled GFRC was studied using thermogravimetric coupled with Fourier-transform infrared spectroscopy (TG-FTIR) at different heating rates. Meanwhile, the volatile products were examined using TG coupled with gas chromatography-mass spectrometry (GC-MS). The TG-FTIR and TG-GC-MS experiments were performed separately. Linear (Kissinger-Akahira-Sunose (KAS), Flynn-Wall-Ozawa (FWO), and Friedman) and nonlinear (Vyazovkin and Cai) isoconversional methods were used to determine the pyrolysis kinetic of the milled GFRC based on thermogravimetry and differential thermal gravimetry (TG/DTG). In addition, the TG/DTG data of the milled GFRC were fitting using the distributed activation energy model and the independent parallel reactions kinetic model. The TG results showed that GFRC can decompose in three stages, and the main decomposition is located in the range 256-500 °C. On the other hand, aromatic benzene and a C-H bond were the major functional groups in the released volatile components in FTIR spectra, while phenol (27%), phenol,4-(1-methylethyl) (40%), and p-isopropenylphenol (34%) were the major compounds in GC-MS analysis. Whereas, the kinetic results showed that both isoconversional methods can be used to determine activation energies, which were estimated 165 KJ/mol (KAS), 193 KJ/mol (FWO), 180 KJ/mol (Friedman), 177 KJ/mol (Vyazovkin), and 174 KJ/mol (Cai).

Rheological Measurements and Structural Analysis of Polymeric Materials.

Rheological measurements of polymer melts are widely used for quality control and the optimization of processing. Another interesting field of rheology is to provide information about molecular parameters of polymers and the structure build-up in heterogeneous polymeric systems. This paper gives an overview of the influence of molar mass, molar mass distribution and long-chain branching on various rheological characteristics and describes the analytical power following from established relations. With respect to applications, we discuss how rheological measurements can be used to gain insight into the thermal stability of a material. A special impact lies in the demonstration, how long-chain branching can be analyzed using rheological means like the zero-shear viscosity as a function of molar mass and strain hardening occurring in elongation. For contributions to branching analysis, the thermorheological behavior and activation energies are particularly discussed. The use of elastic quantities in the case of mechanical pretreatment effects is briefly addressed. The influence of fillers on recoverable properties in the linear range of deformation is analyzed and the role of their specific surface area for interactions described. It is shown how the fundamental results can be applied to study the state of nanoparticle dispersions obtained under special conditions. Furthermore, it is demonstrated that the findings on polymer/filler systems are the base of structure analyses in heterogeneous polymeric materials like polyvinylchloride (PVC) and acrylonitrile-butadiene-styrene copolymers (ABS).

Comparative Study of Eleven Mechanical Pretreatment Protocols for Cryptosporidium parvum DNA Extraction from Stool Samples.

Nowadays, many commercial kits allow the polymerase chain reaction (PCR) detection of Cryptosporidium deoxyribonucleic acid (DNA) in stool samples, the efficiency of which relies on the extraction method used. Mechanical pretreatment of the stools using grinding beads has been reported to greatly improve this extraction step. However, optimization of this key step remains to be carried out. Indeed, many parameters could influence the pretreatment performances, among which the modulation of the speed and duration of the grinding step, in addition to the physicochemical features of the grinding beads, have never been evaluated to date. In this study, eleven commercial mechanical pretreatment matrixes (Lysis matrix tubes®, MP Biomedical, Irvine, CA, USA) composed of beads with different sizes, shapes, and molecular compositions, were evaluated for their performances in improving Cryptosporidium parvum oocyst DNA extraction before amplification by using our routinely used real-time PCR method. As expected, the eleven commercial mechanical pretreatment matrixes showed varying performances depending on the composition, size, and shape. All in all, the best performances were obtained when using the Lysing matrix, including ceramic beads with a median size (diameter of 1.4 mm).