Water Washing Step Research Articles

Multi enzyme production from mixed untreated agricultural residues applied in enzymatic saccharification of lignocellulosic biomass for biofuel

Lignocellulose recalcitrance essentially dictates high cost and low efficiency of its enzymatic saccharification. The complex lignocellulosic structure is a major obstacle to enzymatic saccharification and green ionic liquid pretreatment methods face difficulty of water washing prior enzymatic hydrolysis. Ionic liquid tolerant lignocellulolytic enzymes overcome the inhibition of enzymes during enzymatic saccharification and eliminated water washing step after pretreatment of lignocellulosic biomass. The cell wall composition cellulose, hemicellulose, and lignin, three main wall polymers of various agricultural residues and food waste lignocellulose substrates also affected the enzyme activities secreted by the B. subtilis strain. This study explores the potential of the halophilic, alkalophilic, and ionic liquid (IL)-tolerant strain Bacillus subtilis BC-001 for the simultaneous production of hydrolytic enzymes essential for lignocellulosic bio-refinery processes. BC-001 produced cellulase, amylase, xylanase, pectinase and protease are 70.41, 87.14, 65.50, 122.55 and 66.48 U/mL, respectively under optimized fermentation conditions. Cellulase produced by BC-001 retained more than 80% activity after 72 hours in 20% w/w of different ILs tested and enzymes retained more than 68% activities after 12 h in 50% w/w ILs. Employing such IL-stable cellulase, enzymatic saccharification is conducted without water washing on rice straw (RS) that has been pretreated with various ILs, including 1-ethyl-3-methylimidazolium chloride, 1-butyl-3-methylimidazolium chloride, and choline chloride. This research is novel as the study marks the first instance of multi-hydrolytic enzyme production from a novel alkalophilic, halophilic, thermophilic, and IL-tolerant bacterial strain using a mixture of untreated agricultural residues.

Green solvents extraction-based detoxification to enhance the enzymatic hydrolysis of steam-exploded lignocellulosic biomass and recover bioactive compounds

A novel strategy for pre-treated biomass detoxification combining emerging green solvents and low environmental impact extraction technologies was evaluated. Steam-exploded biomass was subjected to microwave-assisted or orbital shaking extraction using bio-based or eutectic solvents. The extracted biomass was enzymatically hydrolysed. The potential of this detoxification methodology was studied in terms of phenolic inhibitors extraction and sugar production improvement. The effect of adding a post-extraction water washing step before hydrolysis was also evaluated. Excellent results were achieved when steam-exploded biomass was subjected to the microwave-assisted extraction combined with the washing step. The highest sugar production was achieved when ethyl lactate was used as extraction agent (49.80 ± 3.10 g total sugar/L) over the control (30.43 ± 0.34 g total sugar/L). Results suggested that a detoxification step based on green solvents would be a promising option to extract phenolic inhibitors, which can be revalorized as antioxidants, and improve the sugar production from the extracted pre-treated biomass.

New insights into the source of the boron memory effect and implications for accurate boron isotope measurements.

The boron (B) memory effect is a concern for B isotope analysis in inductively-coupled plasma mass spectrometry and a potential cause of poor data comparability between laboratories. It is widely assumed that the memory resides in water droplets on the surface of the spray chamber. However, even without the use of the spray chamber, background subtractions are still required to generate accurate data, therefore additional causes for the memory effect exist, which are investigated here. Different parts of the mass spectrometer were examined to pinpoint the source of a particularly high B background. After identifying the torch as the source of the background, different parts of the torch were soaked in dilute nitric acid, which was analyzed for B over time. B was leached out of the tip of the outer quartz tube of the torch in a fashion similar to borosilicate glass, which suggests the incorporation of B into the silica structure of the torch at high temperatures. Running 3% nitric acid washes effectively reduces the background. B background compositions change based on the solutions run beforehand, therefore different blank subtraction methods generate systematic differences. A new background subtraction method that utilizes B isotope ratios improved the precision by up to 0.14‰. The addition of a water wash step before sample elution led to smaller eluent volumes and improved matrix matching without causing a B breakthrough. An important part of the B memory derives from the torch glass, which incorporates B from sample solutions at high temperatures. Multiple nitric acid washes, matrix matching, blank subtraction, and standard sample bracketing generated accurate B isotope analyses with background/signal ratios as high as 10%, without the need for hazardous chemicals as washes. B isotope values of two sediment standards that represent average post-Archean continental crust were reported.

A Critical Review on Water Overconsumption in Lignocellulosic Biomass Pretreatment for Ethanol Production through Enzymic Hydrolysis and Fermentation

Global demand for renewable and sustainable energy fostered the considerable development of biomass-to-ethanol valorization strategies. Thermochemical pretreatment methods have been proposed to render biomass more amenable to enzymatic and microbial digestion. However, the efforts have not led to its industrial-scale worldwide realization. One of the obstacles to commercialization could be related to water overconsumption, as excessive water washing of the pretreated slurry is often performed to remove inhibitory compounds and residual chemicals after biomass pretreatment. Only increasing solid loading for biomass pretreatment results in ineffective pretreatment performance, more inhibitors formation, and high viscosity, which in turn necessitates the water washing step. A number of physicochemical and biological methods are applied to detoxify the acid-pretreated liquid fraction for enzymatic hydrolysis and fermentation. Among them, alkaline neutralization and liquid–liquid extraction are preferred because of their simple operation and low cost. Seemingly, recycling black liquor for alkali pretreatment offers a pathway to reduce water and chemical consumption, but alkali replenishment and inhibitor accumulation significantly weaken this technology. Interestingly, quite a few studies have removed the water washing and even solid–liquid separation steps after (liquid hot water, Tween 40, and CaO) pretreatment. There is still much room for future studies to render biomass pretreatment more feasible in terms of economic and environmental points of view. This review provides a deep understanding of wastewater generation during biomass upgrading and discusses the solutions to reduce water consumption critically.

Impregnation of preparative high‐performance solid phase extraction chromatography columns by organophosphorus acid compounds

The flexible and reversible preparation of columns for use in high-performance solid phase extraction chromatography by physisorption of organophosphorus acid extractants has been investigated in detail. Two extractants have been evaluated, bis (2-ethyl-1-hexyl) phosphoric acid (HDEHP) and 2-ethyl-1-hexyl (2-ethyl-1-hexyl) phosphonic acid (HEHEHP), but the developed procedure should be broadly applicable to other extractants. The liquid-liquid solubility of the extractants in feed solvents consisting of aqueous ethanol solutions of varying composition has been determined. The total amount of adsorbed extractant has been quantified by complete desorption and elution with ethanol followed by acid-base titrimetry. Column impregnation with feed solutions of varying concentration in the undersaturated region has been systematically evaluated, and the influence of a subsequent water wash step has been explored. It is shown that to achieve a robust and reproducible physisorption, the adsorbed amount of extractant should be determined after the wash step, and care must be taken when using indirect methods of measurement. Equilibrium Langmuir-type adsorption isotherms as a function of the extractant concentration in the feed solution have been determined. Adsorption of HEHEHP is higher than HDEHP for equal feed compositions, but the solubility of HEHEHP is lower, resulting in approximately identical maximum coverage levels. The ability of the resulting columns to separate rare earth elements have been verified for a mixture of eight metals using a combined isocratic and gradient elution of nitric acid.

Importance of pyrolysis temperature and pressure in the concentration of polycyclic aromatic hydrocarbons in wood waste-derived biochars

Biochar addition to soil can lead to potential environmental risks due to its content of polycyclic aromatic hydrocarbons (PAHs). Until now, previous research focused on assessing the influence of pyrolysis peak temperature and feedstock on the formation and evolution of PAHs. Nevertheless, the effects of other important process parameters —such as pressure, gas residence time, and type of carrier gas— have not been comprehensively explored. To fill this gap, a 2-level full factorial design of experiments was conducted to assess the influence of the above-mentioned parameters on the pyrolysis behavior of an untreated wood waste as well as the properties of resulting biochars, including their PAHs contents. Results showed that the highest production of PAHs was reached at lower peak temperatures, whereas an increase in temperature led to a substantial reduction of the final PAHs content. An increased pressure also resulted in a marked decrease in PAHs, probably as a consequence of the higher carrier gas flow rates used under pressurized conditions, which could inhibit the generation of PAHs by condensation and polymerization. The outstanding results obtained from the phytotoxicity assessment for three plant species (barley, watercress, and basil) suggest that PAHs were not the major responsible for the observed short-term phytotoxic effects of biochars, since a considerable part of the phytotoxic compounds in biochar can be removed by a simple water washing step.

Production of Yellow Poplar Interior Plywood with Cottonseed-based Protein Adhesives

Defatted cottonseed (CS) and water-washed CS meals were prepared from glandless CS and were used in adhesive formulations to produce three-ply yellow poplar plywood panels. Adhesive resins were prepared from each protein meal with sodium bisulfite and one of two polyamido-amine-epichlorohydrin (PAE) wet strength agents, and the plywood panels were produced by hot pressing. Shear strength and water resistance were determined by American Society of Testing and Materials (ASTM) and American National Standards Institute for Hardwood and Decorative Plywood/Hardwood Plywood and Veneer Association (ANSI/HPVA) methods and were compared with the properties of plywood panels made with an adhesive formulated from a commercial soybean meal. Panels prepared from three protein meals had comparable shear strengths. The combinations of the two CS preparations and the two wet strength agents produced panels with acceptable wet resistant properties, whereas the soybean meal only produced acceptable panels with one of the wet strength agents. Because the panels prepared from the two CS meals had comparable properties, there appears to be no benefit to including a water-washing step to increase the meal’s protein level. In contrast with recent literature reports suggesting the addition of alkali to elevate the formulation pH was necessary with CS meal, suitable panels were prepared herein without the addition of the base. This difference may have been due to the slightly higher pressing temperature and longer press times used in this work compared with earlier results. The CS meals showed promise as formaldehyde-free hardwood-plywood wood-based adhesives for interior applications.

Technoeconomic Assessment of a Biomass Pretreatment + Ionic Liquid Recovery Process with Aprotic and Choline Derived Ionic Liquids

Ionic liquids have shown promising results in biomass pretreatment; however, an extensive water washing step is necessary. This fact increases not only the processing costs but also those associated with the ionic liquid recovery step. In this work, Eucalyptus globulus wood pretreated with two acetate-based ionic liquids, namely 1-ethyl-3-methylimidazolium acetate and choline acetate, has been washed with increasing volumes of water in order to analyze the influence of the amount of washing water used on the subsequent enzymatic hydrolysis stage and on the IL recovery costs. Vapor–liquid equilibria data of recovered ionic liquid/water mixtures have been determined to simulate the IL recovery step with Aspen Plus, calculating the operating costs using the Aspen Plus Economics Analyzer afterward. [Emim][OAc] was more efficiently washed and more effective toward wood pretreatment than [Ch][OAc]. Both IL/water systems were successfully modeled, and simulation studies showed that incremental volumes of water led to higher operating costs in the IL recovery step that are compensated with less IL makeup costs. Therefore, this work offers a technoeconomical analysis of the IL recovery step in a real biorefinery pretreatment process as a function of the volume of water used in the pretreated wood washing stage.

The challenge of deodorizing post-consumer polypropylene packaging: Screening of the effect of washing, color-sorting and heat exposure

For promoting a sustainable end-of-life-management for plastic packaging, mechanical recycling of especially post-consumer plastic packaging waste constantly gains more attention. To fulfill both industrial and consumer demands, and to increase the recycled content in new applications, high-quality recyclates are of prime importance. However, the odor contamination of post-consumer polyolefin recyclates is not only limiting their application field but is also of concern for the recycling industry and plastic converters since odor emissions during processing might affect the workers’ well-being. As the development of targeted odor reduction strategies requires detailed insights into causative odorants, the present study addresses the odor characterization of different recycled post-consumer polypropylene from the packaging sector by coupling human sensory and comprehensive instrumental analyses. Thereby, the impact of different washing procedures and color sorting were evaluated in terms of their odor reduction potential. In contrast to color sorting, implementation of a hot water washing step led to a noteworthy odor reduction since intensity ratings declined from 7.4 to 4.0, albeit the odor intensity was still not comparable to the low odor level of investigated virgin polypropylene (intensity rating of 2.1). Moreover, a screening on heat-induced emissions of odorous contaminants inspired by a standard extrusion process was performed, revealing a greater emission of odorants in terms of both number and perceived intensities with increasing temperature.

A Salt Controlled Scalable Approach for Formation of Polyelectrolyte Complex Fiber†

Summary of main observation and conclusionA new scalable approach is reported here for producing the polyelectrolyte complex (PEC) fiber of alginate (ALG) and poly(diallyldimethylammonium chloride) (PDDA). Salt (LiBr, NaBr, or KBr) is used to restrict the complexation of negatively charged ALG and positively charged PDDA in solution to obtain spinnable fluid that can be directly extruded into the coagulation bath to form nascent fiber. A water washing step is adopted right after the formation of nascent fiber to eliminate the defects in fiber. Morphology and mechanical properties of the as‐prepared ALG/PDDA complex fiber are found to be greatly affected by the water washing, as well as the amount and the type of salt used. As the reported approach is similar to the wet‐spinning process which is a commonly used method for industrial production of fibers, it is promising to be applied in larger scale production of PEC fibers.

Effect of Acid Treatment on the Functionalization of Surface, Structural and Textural Properties of Carbon Nanotubes Taunit

The role of acid treatment of Taunit carbon nanotubes in the formation of oxygen-containing functional groups on its surface as well as morphological and textural properties was studied. Acid treatment was carried out in an HNO3 solution or its mixture with H2SO4 under mild conditions (85 °C/1 h) with subsequent washing with distilled water or without washing. Properties of the initial and oxidized samples were investigated using elemental carbon, hydrogen, nitrogen, oxygen (CHNO) analysis, BET (Brunauer-Emmett-Teller) determination of surface area, X-ray diffraction, Raman and Fourier Transform Infrared Spectroscopy (FTIR) spectroscopy, and hydrogen temperature-programmed reduction. Treatment with HNO3 and HNO3/H2SO4 mixture was shown to be efficient for the formation of various oxygen-containing groups on the Taunit surface; therewith, the water washing step also contributed to functionalization of the surface. Depending on the oxidant, acid treatment increased graphite and oxygen content in the samples by a factor of 3‒4.5. Treatment with HNO3 without water washing exerted a weak effect on the graphite structure ordering, the concentration of aliphatic groups was high as compared to other oxidation conditions. Treatment of Taunit with the HNO3/H2SO4 mixture, on the contrary, increased the number of defects in graphite layers and decreased the concentration of aliphatic structures.

RETRACTED: Corn stover pretreatment by metal oxides for improving lignin removal and reducing sugar degradation and water usage

Five metal oxides, Fe2O3, CuO, NiO, ZnO, and MgO, were investigated as catalysts to improve lignin removal and reduce sugar degradation during corn stover pretreatment. Liquid hot water (LHW) pretreatment was used as control. Among the five metal oxides, MgO was the most suitable for biomass pretreatmen. The optimal pretreatment condition was the solid/liquid ratio of 1/10 with 0.10 mol/L MgO at 190 °C for 40 min. The fermentable xylose (85%) and glucose (97%) from MgO pretreatment were equivalent to those (89 and 95%) from LHW pretreatment, and lignin removal was 1.5-fold more than that from LHW pretreatment. The pH of the resulting biomass slurry was close to 7.0 and without furfural and 5-hydroxymethylfurfural formation. Thus, the water-washing step for inhibitor removal can be omitted. The biomass liquor can be used directly for downstream hydrolysis and fermentation. Acid-resistant equipment is not required due to the absence of acids.

EFFECT OF NONIONIC SURFACTANTS ON THE REMOVAL OF PAH FROM CONTAMINATED SOIL

In this study, a soil washing process in the presence of a nonionic surfactant solution of Tween 80 or Triton X-100 was investigated. Sandy soil was contaminated in the laboratory with naphthalene (10 mg/kg and 5000 mg/kg) and anthracene (25 mg/kg and 200 mg/kg), then washed with surfactant solution. A preliminary water washing step showed the performance of water in the removal of the two polycyclic aromatic hydrocarbons (PAH), especially naphthalene. The effect of Tween 80 and Triton X-100 was significant beyond the critical micellar concentration (CMC), where a concentration of 7 or 10CMC showed a great efficiency in removing PAH. Also, the effect of these surfactants was shown remarkably affected by the pH and the ionic strength.

Production and purification of biodiesel produced from used frying oil using hydrodynamic cavitation

This work describes the biodiesel production from used frying oil using a hydrodynamic cavitation reactor as well as separation and purification of fatty acid methyl esters (FAME). Under the optimized process conditions, i.e., methanol to oil molar ratio of 4.5:1 and catalyst (KOH) concentration of 0.55 wt%, the conversion achieved was 93.86 mol%. Higher conversion (93.6%) was obtained in only 20 min as compared to 88.5% in 1 h in stirred tank reactor. Due to the completion of transesterification reaction, the amount of intermediate diglycerides and monoglycerides present in the reaction mixture was less. It helps for the complete separation of methyl ester and glycerol layers without hindrance in 1 h. Small amount KOH catalyst used for completion of reaction reduces amount of KOH and soap in ester layer which further helps to form a less stable emulsion during water washing step. The complete separation was observed at 70 °C temperature in just 3 h. Thus, this study indicates that the increased production capacity can be achieved by shortening the time for the separation and purification.

Production and purification of biodiesel produced from used frying oil using hydrodynamic cavitation

This work describes the biodiesel production from used frying oil using a hydrodynamic cavitation reactor as well as separation and purification of fatty acid methyl esters (FAME). Under the optimized process conditions, i.e., methanol to oil molar ratio of 4.5:1 and catalyst (KOH) concentration of 0.55 wt%, the conversion achieved was 93.86 mol%. Higher conversion (93.6%) was obtained in only 20 min as compared to 88.5% in 1 h in stirred tank reactor. Due to the completion of transesterification reaction, the amount of intermediate diglycerides and monoglycerides present in the reaction mixture was less. It helps for the complete separation of methyl ester and glycerol layers without hindrance in 1 h. Small amount KOH catalyst used for completion of reaction reduces amount of KOH and soap in ester layer which further helps to form a less stable emulsion during water washing step. The complete separation was observed at 70 °C temperature in just 3 h. Thus, this study indicates that the increased production capacity can be achieved by shortening the time for the separation and purification.

Clinical performance evaluation of total protein measurement by digital refractometry and characterization of non-protein solute interferences

ObjectivesRefractometric methods to measure total protein (TP) in serum and plasma specimens have been replaced by automated biuret methods in virtually all routine clinical testing. A subset of laboratories, however, still report using refractometry to measure TP in conjunction with serum protein electrophoresis. The objective of this study was therefore to conduct a modern performance evaluation of a digital refractometer for TP measurement. Design and methodsPerformance evaluation of a MISCO Palm Abbe™ digital refractometer was conducted through device familiarization, carryover, precision, accuracy, linearity, analytical sensitivity, analytical specificity, and reference interval verification. Comparison assays included a manual refractometer and an automated biuret assay. ResultsCarryover risk was eliminated using a demineralized distilled water (ddH2O) wash step. Precision studies demonstrated overall imprecision of 2.2% CV (low TP pool) and 0.5% CV (high TP pool). Accuracy studies demonstrated correlation to both manual refractometry and the biuret method. An overall positive bias (+5.0%) was observed versus the biuret method. On average, outlier specimens had an increased triglyceride concentration. Linearity was verified using mixed dilutions of: a) low and high concentration patient pools, or b) albumin-spiked ddH2O and high concentration patient pool. Decreased recovery was observed using ddH2O dilutions at low TP concentrations. Significant interference was detected at high concentrations of glucose (>267mg/dL) and triglycerides (>580mg/dL). Current laboratory reference intervals for TP were verified. ConclusionsPerformance characteristics of this digital refractometer were validated in a clinical laboratory setting. Biuret method remains the preferred assay for TP measurement in routine clinical analyses.

An Alternative Method For The Development Of 3D Engineered Neuronal Cultures

An Alternative Method For The Development Of 3D Engineered Neuronal Cultures

Effect of the Processing Steps (Harvesting Time to Pasteurization) on Percentage of Fatty Acids in Table Olive

The properties of fatty acids (FA) of four olive cultivars (Mari, Zard Golole, Roghani, and Souri) during crude state, lye treatment, water washing, fermentation, and pasteurization steps were studied. According to the results obtained, during the processing steps, in all the cultivars, oleic, palmitic, linoleic, and stearic acids were higher; the highest changes in saturated and unsaturated fatty acids (SFAs (saturated fatty acids) and UFAs (unsaturated fatty acids), respectively) were in water washing and lye treatment steps, and water washing and pasteurization steps, respectively; the highest and the lowest ratios of ω6/ ω3 fatty acids were in Zard Golole (crude state) and Souri (water washing step), respectively. Keywords: Table olive, variety, processing step, fatty acid.

Quantitative method for the determination of iso-fludelone (KOS-1803) in human plasma by LC–MS/MS

Epothilones are relatively new tubulin-poison anticancer drugs. Iso-fludelone (KOS-1803) is a synthetic third generation epothilone drug discovered at Memorial Sloan Kettering Cancer Center, and currently in phase I clinical trials. We report an LC–MS/MS assay for the sensitive, accurate and precise quantitation of iso-fludelone in 0.2mL of human plasma. Validation was performed according to FDA guidance. The assay comprised of KOS-1724 as the internal standard and an MTBE liquid–liquid extraction with a water wash step. Separation was achieved with an YMC-Pack ODS-AQ column and an isocratic mobile phase of 0.1% formic acid in acetonitrile and water (70:30, v/v) at 0.3mL/min for 4min. Chromatographic separation was followed by electrospray, positive-mode ionization tandem mass spectrometric detection in the multiple reaction monitoring (MRM) mode. The assay was linear from 0.1 to 300ng/mL and was accurate (−9.41 to −7.07%) and precise (1.03–13.7%) which fulfilled FDA criteria for validation. Recovery from plasma was 73.9–79.7% and ion suppression was negligible (−22.8 to −31.3%). Plasma freeze–thaw stability (99.97–105.7%), stability for 11 months at −80°C (94.93–107.9%), and stability for 6h at room temperature (94.75–105.5%) were all acceptable. This assay is currently being applied to quantitate iso-fludelone in clinical samples.

Understanding cost drivers and economic potential of two variants of ionic liquid pretreatment for cellulosic biofuel production.

BackgroundIonic liquid (IL) pretreatment could enable an economically viable route to produce biofuels by providing efficient means to extract sugars and lignin from lignocellulosic biomass. However, to realize this, novel IL-based processes need to be developed in order to minimize the overall production costs and accelerate commercial viability. In this study, two variants of IL-based processes are considered: one based on complete removal of the IL prior to hydrolysis using a water-wash (WW) step and the other based on a “one-pot” (OP) process that does not require IL removal prior to saccharification. Detailed techno-economic analysis (TEA) of these two routes was carried out to understand the cost drivers, economic potential (minimum ethanol selling price, MESP), and relative merits and challenges of each route.ResultsAt high biomass loading (50%), both routes exhibited comparable economic performance with an MESP of $6.3/gal. With the possible advances identified (reduced water or acid/base consumption, improved conversion in pretreatment, and lignin valorization), the MESP could be reduced to around $3/gal ($3.2 in the WW route and $2.8 in the OP route).ConclusionsIt was found that, to be competitive at industrial scale, lowered cost of ILs used and higher biomass loadings (50%) are essential for both routes, and in particular for the OP route. Overall, while the economic potential of both routes appears to be comparable at higher biomass loadings, the OP route showed the benefit of lower water consumption at the plant level, an important cost and sustainability consideration for biorefineries.