Enzymatic digestibility of lignocellulosic wood biomass: Effect of enzyme treatment in supercritical carbon dioxide and biomass pretreatment.

Energy and resource intensive mechanical and chemical pretreatment along with the use of hazardous chemicals are major bottlenecks in widespread lignocellulosic biomass utilization. Herein, the study investigated different pretreatment methods on spruce wood namely supercritical CO2 (scCO2) pretreatment, ultrasound-assisted alkaline pretreatment, and acetosolv pulping-alkaline hydrogen peroxide bleaching, to enhance the enzymatic digestibility of wood using optimized enzyme cocktail. Also, the effect of scCO2 pretreatment on enzyme cocktail was investigated after optimizing the concentration and temperature of cellulolytic enzymes. The impact of scCO2 and ultrasound-assisted alkaline pretreatments of wood were insignificant for the enzymatic digestibility, and acetosolv pulping-alkaline hydrogen peroxide bleaching was the most effective pretreatment that showed the release of total reducing sugar yield (TRS) of ∼95.0 wt% of total hydrolyzable sugars (THS) in enzymatic hydrolysis. The optimized enzyme cocktail showed higher yield than individual enzymes with degree of synergism 1.34 among the enzymes, and scCO2 pretreatment of cocktail for 0.5-1.0 h at 10.0-22.0 MPa and 38.0-54.0 °C had insignificant effect on the enzyme's primary and global secondary structure of cocktail and its activity.

Biodegradation of 1,4-dioxane in a continuous-flow bioelectrochemical reactor by biofilm of Pseudonocardia dioxanivorans CB1190 and microbial community on conductive carriers.

Bioelectrochemical degradation is an environmentally friendly, cost-effective and controllable way of providing electron acceptor to the microorganisms. A two-chamber continuous-flow bioelectrochemical reactor (BER) was developed in this study. The objective was to investigate the potential for enhancing the bioelectrochemical degradation of 1,4-dioxane (DX) by Pseudonocardia dioxanivorans CB1190 (CB1190) and microbial community biofilm on conductive and non-conductive carriers in low potentials (1.0-1.2 V) and currents (<2 mA). In the case of CB1190, biodegradation experiments at 1.0 V did not result in any observable change in DX removal efficiency (32.63 ± 2.48%) compared to the 0.0 V (31.69 ± 2.33%). However, the removal efficiency was much higher at 1.2 V (59.08 ± 0.86%). The higher removal at 1.2 V was attributed to an increase in dissolved oxygen (DO) concentration from 3.77 ± 0.33 mg/L at 0.0 V to 5.40 ± 0.11 mg/L at 1.2 V, which resulted from water electrolysis. In the case of microbial community, on the other hand, DX removal efficiency increased at 1.0 V (30.98 ± 1.10%) compared to 0.0 V (23.40 ± 1.02%) that can be attributed to a simultaneous increase in microbial activity from 2389 ± 118.5 ngATP/mgVSS at 0.0 V to 2942 ± 109 ngATP/mgVSS at 1.0 V. Analysis of the changes in microbial composition indicated enrichment of Alistipes and Lutispora at 1.0 V due to the ability of these genera to directly transfer electrons with conductive surface. On the other hand, no change was observed in the microbial community in the case of non-conductive carriers. Results of this study showed that electro-assisted biodegradation of DX at low potentials is possible through two different mechanisms (oxygen production and direct electron transfer with electrode) which makes this technique flexible and cost-effective. The novelty of this work lies in exploring the use of electrical assistance to enhance the biodegradation of DX in the presence of CB1190 and the microbial community. This study more specifically investigated lower potential than required water electrolysis potential, allowing microorganisms to be stimulated through mechanisms unrelated to oxygen generation.

Influence of elevated pressure and pressurized fluids on microenvironment and activity of enzymes.

Enzymes have great potential in bioprocess engineering due to their green and mild reaction conditions. However, there are challenges to their application, such as enzyme extraction and purification costs, enzyme recovery, and long reaction time. Enzymatic reaction rate enhancement and enzyme immobilization have the potential to overcome some of these challenges. Application of high pressure (e.g., hydrostatic pressure, supercritical carbon dioxide) has been shown to increase the activity of some enzymes, such as lipases and cellulases. Under high pressure, enzymes undergo multiple alterations simultaneously. High pressure reduces the bond lengths of molecules of reaction components and causes a reduction in the activation volume of enzyme-substrate complex. Supercritical CO2 interacts with enzyme molecules, catalyzes structural changes, and removes some water molecules from the enzyme's hydration layer. Interaction of scCO2 with the enzyme also leads to an overall change in secondary structure content. In the extreme, such changes may lead to enzyme denaturation, but enzyme activation and stabilization have also been observed. Immobilization of enzymes onto silica and zeolite-based supports has been shown to further stabilize the enzyme and provide resistance towards perturbation under subjection to high pressure and scCO2.

Biodegradation of 1,4-dioxane by a native digestate microbial community under different electron accepting conditions.

The potential of a native digestate microbial community for 1,4-dioxane (DX) biodegradation was evaluated under low dissolved oxygen (DO) concentrations (1-3 mg/L) under different conditions in terms of electron acceptors, co-substrates, co-contaminants and temperature. Complete DX biodegradation (detection limit of 0.01 mg/L) of initial 25 mg/L was achieved in 119 days under low DO concentrations, while complete biodegradation happened faster at 91 and 77 days, respectively in nitrate-amended and aerated conditions. In addition, conducting biodegradation at 30 ˚C showed that the time required for complete DX biodegradation in unamended flasks reduced from 119 days in ambient condition (20-25 °C) to 84 days. Oxalic acid, which is a common metabolite of DX biodegradation was identified in the flasks under different treatments including unamended, nitrate-amended and aerated conditions. Furthermore, transition of the microbial community was monitored during the DX biodegradation period. While the overall richness and diversity of the microbial community decreased, several families of known DX-degrading bacteria such as Pseudonocardiaceae, Xanthobacteraceae and Chitinophagaceae were able to maintain and grow in different electron-accepting conditions. The results suggested that DX biodegradation under low DO concentrations, where no external aeration was provided, is possible by the digestate microbial community, which can be helpful to the ongoing research for DX bioremediation and natural attenuation.

Delignified porous wood as biofilm support for 1,4-dioxane-degrading bacterial consortium.

Delignified porous wood samples were used as carriers for biofilm formation of a bacterial consortium with the ability to degrade 1,4-dioxane (DX). The delignification treatment of the natural wood resulted in higher porosity, formation of macropores, increase in surface roughness and hydrophilicity of the treated wood pieces. These superior properties of two types of treated carriers (respectively, A and B) compared to the untreated wood resulted in 2.19 ± 0.52- and 2.66 ± 0.23-fold higher growth of biofilm. Moreover, analysis of the fatty acid profiles indicated an increase in proportion of the saturated fatty acids during the biofilm formation, characterising an enhancement in rigidity and hydrophobicity of the biofilms. DX initial concentration of 100 mg/L was completely degraded (detection limit 0.01 mg/L) in 24 and 32 h using the treated A and B woods, while only 25.84 ± 5.95% was removed after 32 h using the untreated wood. However, fitting the DX biodegradation data to the Monod model showed a lower maximum specific growth rate for biofilm (0.0276 ± 0.0018 1/h) versus planktonic (0.0382 ± 0.0024 1/h), because of gradual accumulation of inactive cells in the biofilm. Findings of this study can contribute to the knowledge of biofilm formation regarding the physical/chemical properties of biofilm carriers and be helpful to the ongoing research on bioremediation of DX.

Nanocrystalline cellulose derived from spruce wood: Influence of process parameters.

The cellulose nanocrystals (CNCs) were produced from spruce wood using less hazardous and toxic reagents with understanding of influence of process parameters on CNCs properties. This study employed acetosolv pulping followed by alkaline-peroxide bleaching, eliminating highly reactive chemicals such as Na-chlorites and Na-sulfite for cellulose pulp extraction from spruce wood. Cellulose pulp yield of 41.5 ± 0.7 wt% of dry wood was obtained from pulping followed by bleaching treatment. Cellulose pulp was hydrolyzed with 59.0-65.0 wt% sulfuric acid followed by ultrasonic treatment to produce CNCs. CNCs yield of 8.0 ± 3.2 wt% of dry wood was obtained at 65 wt% acid concentration and yield of 25.1 ± 0.7 wt% at 62 wt% acid concentration. The optimization of acid hydrolysis and ultrasonic treatment resulted in CNCs with high aspect ratios (length/width) up to 48.1. It was demonstrated that higher acid concentration requires lower intensity of ultrasonic treatment for CNCs dispersion, and that higher intensity could enhance aspect ratio without impacting the crystallinity index. However, ultrasonic treatment for longer than 5 min led to destruction of the whisker morphology of CNCs. The extracted CNCs possess high crystallinity index of 80.8 ± 1.7 %, low residual hemicellulose (<2.0 %) and lignin (<0.7 %), and high-char content of 26.7 wt% from thermal degradation.

Algal Polysaccharides-Based Hydrogels: Extraction, Synthesis, Characterization, and Applications.

Hydrogels are three-dimensional crosslinked hydrophilic polymer networks with great potential in drug delivery, tissue engineering, wound dressing, agrochemicals application, food packaging, and cosmetics. However, conventional synthetic polymer hydrogels may be hazardous and have poor biocompatibility and biodegradability. Algal polysaccharides are abundant natural products with biocompatible and biodegradable properties. Polysaccharides and their derivatives also possess unique features such as physicochemical properties, hydrophilicity, mechanical strength, and tunable functionality. As such, algal polysaccharides have been widely exploited as building blocks in the fabrication of polysaccharide-based hydrogels through physical and/or chemical crosslinking. In this review, we discuss the extraction and characterization of polysaccharides derived from algae. This review focuses on recent advances in synthesis and applications of algal polysaccharides-based hydrogels. Additionally, we discuss the techno-economic analyses of chitosan and acrylic acid-based hydrogels, drawing attention to the importance of such analyses for hydrogels. Finally, the future prospects of algal polysaccharides-based hydrogels are outlined.

Transformation under pressure: Discovery of a novel crystalline form of anthelmintic drug Praziquantel using high-pressure supercritical carbon dioxide.

Supercritical carbon dioxide (CO2) has been used as a processing technique to control polymorphism of pharmaceuticals. However, there are fewer reports of novel polymorphs being discovered by supercritical CO2 processing. As supercritical crystallization methods gain attention for potential in pharmaceutical processing, they may become a critical screening tool for discovery of new polymorphs. In this work, a case study is presented for a novel crystalline form of the anthelmintic drug, Praziquantel, found through supercritical CO2 processing. The novel form of Praziquantel was characterized by chromatography, nuclear magnetic resonance and infrared spectroscopy, X-ray powder diffraction, thermal analysis, and scanning electron microscopy. Furthermore, the novel form exhibited 13-20% improved solubility compared to commercial Form A between pH 1.6 and 7.5 and was physically stable under stressed conditions (40 °C and 75% relative humidity) for 7.5 weeks. Overall, this work showed that supercritical CO2 processing is a valuable tool to screen for novel, and possibly viable polymorphs of pharmaceutical compounds with improved properties.

Ternary Phase Diagram Development and Production of Niclosamide-Urea Co-Crystal by Spray Drying.

In this work, a ternary phase diagram was developed for a Niclosamide-urea co-crystal (NCS-UR) in isopropanol (IPA) using a combination of slurry and solvent addition methods. The ternary phase diagram showed that solubility of Niclosamide and urea differed by an order of magnitude in IPA, leading to an incongruently saturating system. Spray drying was explored as a method to generate NCS-UR. Co-crystals with small, uniform particle size were successfully prepared by spray drying from equimolar solutions with yield up to 73%. Co-crystals were phase pure by X-ray powder diffraction (XRPD) and differential scanning calorimetry (DSC) from all conditions explored. Somewhat similar particles were obtained at inlet temperature of 70 °C (mean size of 2.0 µm) compared to 85 °C (2.8-3.4 µm). Based on the TPD, isolating phase pure co-crystal through solution crystallization in IPA would require excess urea. However, spray drying did not require excess co-former. The in-vitro solubility of NCS-UR was compared to anhydrous NCS in biorelevant media. NCS-UR did not give improvement in solubility at 1 h or 24 h. Overall, this work showed that spray drying is a feasible process for preparing phase pure co-crystals for an incongruently saturating system and simultaneously generating micron size particles.

Physical and biological removal of Microcystin-LR and other water contaminants in a biofilter using Manganese Dioxide coated sand and Graphene sand composites.

Sand as a filter media is often challenged by the presence of organics in the form of natural organic matter, metal ions, and various micropollutants in the source water. It is mainly due to the presence of limited active adsorption sites and low surface area that governs an ineffective adsorption potential of the sand material. Herein, graphitized sand was synthesized to tackle the above limitations using two sugar solution sources: a) brewery effluent (as a low-cost solution) (GS1) and; b) sucrose solution (GS2). GS1 showed 68%, 60%, and 99% higher maximum adsorption constant (qmax) for divalent metal ions: iron, copper, and manganese, respectively as compared to raw sand (RS). Coating of MnO2 over the graphitized sand (GSMs: GS1M and GS2M) further helped in Microcystin-LR (MC-LR) removal (3%-9%) when inoculated with MC-LR-degraders, but was not as effective in removing metals, organic carbon and nitrogen when compared to just graphitized sand (GS1 or GS2). Inoculating GS and GSMs (for both sugar sources) not only helped in higher MC-LR removal (10%-15% more) but also enhanced the removal of other water contaminants including metals, organic nitrogen, and carbon. GS1 showed 20% and 50% more MC-LR removal than the sand material when tested at a low and high initial concentration of MC-LR (5 µg/L and 50 µg/L). The highest breakthrough period was obtained for GS1 filter using 1 mg/L Rhodamine-B dye, which was 12 times (48 min) more than the raw sand filter and almost 2.5 times (second best, 21 min) than GS1M. After three cycles of regeneration and reuse of GS1 filter, a decrease of just 14% in saturation adsorption capacity indicated its high reusability aspects.

Dataset of breakthrough time for various modified sand materials using Rhodamine-B as an adsorbate.

Removal of synthetic dyes from wastewater generated by the textile industries is important. Rhodamine-B is widely used colorant and is medically proven to lead to tissue borne sarcoma, reproductive and neurotoxicity issues in humans, if still present in the treated drinking water. Herein, this dataset provides information on different forms of sand materials for their effective utilization as an adsorbent material for Rhodamine-B. The effectiveness of the media was measured in terms of breakthrough time obtained. One of the 27 presented data set is a part of a research article [1] explaining the breakthrough time of these filter media under specific experimental condition. All these data is a combination of three variables that were studied: a) concentration of Rhodamine-B (1 mg/L, 5 mg/L and 10 mg/L), b) flow velocity of Rhodamine-B spiked water (2 mL/min, 5 mL/min and 10 mL/min) and c) bed height (7.5 cm, 10 cm, and 12.5 cm). At any bed height, the breakthrough time of graphitized sand (brewery sugar coated, GS1) was found to be 3-4 times higher than the second best adsorbent, i.e., manganese dioxide coated on GS1.

Agro-industrial residues as a unique support in a sand filter to enhance the bioactivity to remove microcystin-Leucine aRginine and organics.

In the past, the versatility of a biosand filter has been successfully checked to counter suspended solids, metals, dissolved organic carbon (DOC), coliforms and other water quality parameters (WQPs) from the drinking water sources. In this study, cyanotoxin in the form of microcystin-LR (MC-LR) along with above-mentioned WQPs including nitrate, nitrite, and ammonia are analyzed for their removal using agro-residue based biosand filters (ARSFs) for 49 days (7 cycles). Three different agro-residue materials (ARMs) viz. deinking sludge (DSF), hemp fiber (HFF) and paper-pulp dry sludge (PPF) were used as the support material (top 5 cm) along with sand (49 cm) as the primary filter media to enhance the overall bioactivity. This enhancement in bioactivity is hypothesized to remove more MC-LR, DOC, coliform along with efficient nitrification/denitrification. Native bacterial community isolated from the filtration unit of a drinking water treatment plant (Chryseobacterium sp. and Pseudomonas fragi = X) along with the MC-LR-degrader: Arthrobacter ramosus (which was screened as the best biofilm-former among two other MC-LR-degraders tested) were used to inoculate the filters (all three ARSFs). Overall, DSF performed the best among all the ARSFs when compared to the sand filter (SFI) inoculated with the same bacterial strains (A + X). An increase in the bioactivity for ARSFs, particularly DSF was evident from the DOC removal (44 ±â€¯11%, 15% more than SFI), coliform removal (92.7 ±â€¯12.8%, 24% more than SFI), MC-LR removal (87 ±â€¯14%, 13% more than SFI) and an effective nitrification/denitrification, reducing ammonia, nitrate and nitrite level to below guideline values. Toxic assessment using bioindicator (Rhizobium meliloti) revealed safe filter water only in case of DSF.

Potential of biological approaches for cyanotoxin removal from drinking water: A review.

Biological treatment of cyanotoxins has gained much importance in recent decades and holds a promise to work in coordination with various physicochemical treatments. In drinking water treatment plants (DWTPs), effective removal of cyanotoxins with reduced toxicity is a primary concern. Commonly used treatments, such as ozonation, chlorination or activated carbon, undergo significant changes in their operating conditions (mainly dosage) to counter the variation in different environmental parameters, such as pH, temperature, and high cyanotoxin concentration. Presence of metal ions, natural organic matter (NOM), and other chemicals demand higher dosage and hence affect the activation energy to efficiently break down the cyanotoxin molecule. Due to these higher dose requirements, the treatment leads to the formation of toxic metabolites at a concentration high enough to break the guideline values. Biological methods of cyanotoxin removal proceed via enzymatic pathway where the protein-encoding genes are often responsible for the compound breakdown into non-toxic metabolites. However, in contrast to the chemical treatment, the biological processes advance at a much slower kinetic rate, predominantly due to a longer onset period (high lag phase). In fact, more than 90% of the studies reported on the biological degradation of the cyanotoxins attribute the biodegradation to the bacterial suspension. This suspended growth limits the mass transfer kinetics due to the presence of metal ions, NOMs and, other oxidizable matter, which further prolongs the lag phase and makes biological process toxic-free, albeit less efficient. In this context, this review attempts to bring out the importance of the attached growth mechanism, in particular, the biofilm-based treatment approaches which can enhance the biodegradation rate.

Fabrication of nanobiocatalyst using encapsulated laccase onto chitosan-nanobiochar composite.

Laccase is one of the widely used enzymes for biotechnological processes. Immobilization of enzymes is a universally accepted approach to increase their reusability and stability. In this study, laccase enzyme from Trametes versicolor was encapsulated for the first time in a chitosan-nanobiochar matrix. The chitosan-tripolyphosphate gel formation technique was employed to produce homogeneous biocatalyst nanoparticles, with 35% effective binding efficiency and 3.5 Units/g apparent activity under the best configuration. The reusability of the encapsulated laccase was demonstrated towards the oxidation of 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS) for several consecutive cycles, exhibiting 30% of the initial activity after 5 cycles. The encapsulated laccase showed a moderate increase in enzyme stability against pH and temperature variation compared to the free enzyme. Moreover, the storage stability of laccase at both 4 °C and 25 °C was increased after immobilization. Only 2% of laccase was leaked during a 5-day period from biocatalyst. Laccase in its free form showed no antibacterial activity against Gram positive and Gram-negative model microorganisms, while encapsulated laccase showed antibacterial activity towards Gram-positive ones. Thus, the encapsulation of the laccase is an efficient method to keep the enzyme active and stable for different applications.

Biodegradation of microcystin-LR using acclimatized bacteria isolated from different units of the drinking water treatment plant.

Bacterial community isolated from different units of a Drinking Water Treatment Plant (DWTP) including pre-ozonation unit (POU), the effluent-sludge mixture of the sedimentation unit (ESSU) and top-sand layer water sample from the filtration unit (TSFU) were acclimatized separately in the microcystin-leucine arginine (MC-LR)-rich environment to evaluate MC-LR biodegradation. Maximum biodegradation efficiency of 97.2 ±â€¯8.7% was achieved by the acclimatized-TSFU bacterial community followed by 72.1 ±â€¯6.4% and 86.2 ±â€¯7.3% by acclimatized-POU and acclimatized-ESSU bacterial community, respectively. Likewise, the non-acclimatized bacterial community showed similar biodegradation efficiency of 71.1 ±â€¯7.37%, 86.7 ±â€¯3.19% and 94.35 ±â€¯10.63% for TSFU, ESSU and POU, respectively, when compared to the acclimatized ones. However, the biodegradation rate increased 1.5-folds for acclimatized versus non-acclimatized conditions. The mass spectrometry studies on MC-LR degradation depicted hydrolytic linearization of cyclic MC-LR along with the formation of small peptide fragments including Adda molecule that is linked to the reduced toxicity (qualitative toxicity analysis). This was further confirmed quantitatively by using Rhizobium meliloti as a bioindicator. The acclimatized-TSFU bacterial community comprised of novel MC-LR degrading strains, Chryseobacterium sp. and Pseudomonas fragi as confirmed by 16S rRNA sequencing.

Pinewood nanobiochar: A unique carrier for the immobilization of crude laccase by covalent bonding.

Nanotechnology-inspired biocatalytic systems attracted attention for many applications since nanosized supports for enzyme immobilization can improve efficiency-determining factors e.g. enhancing the surface area and loading capacity and reducing the mass transfer resistance. Among the nanomaterials, nanobiochar has unique features as a support for enzyme immobilization i.e. high surface to volume ratio, porous structure, and presence of functional groups on its surface. However, the performance of the immobilization is highly dependent on the immobilization conditions and the properties of the enzyme and the support material. In this research, crude laccase was covalently immobilized onto functionalized nanobiochar using a two-step method of diimide-activated amidation. The effect of different parameters was investigated. The optimal conditions were found to be 14 mg/mL of laccase concentration, 5 mg/mL of nanobiochar, 8.2 mM of cross-linker and 3 h of contact time. For investigating the pH, thermal, storage, and operational stability, the sample obtained from the optimized conditions was used. The results showed the higher stability of immobilized laccase against temperature and pH variation compared to free laccase. In addition, immobilized laccase maintained its catalytic performance up to seven cycles of utilization and showed more than 50% of initial activity after two months of room temperature storage.

Anaerobic digestion of thin stillage of corn ethanol plant in a novel anaerobic baffled reactor.

In this study, the performance of a conventional anaerobic baffled reactor (ABR) and a novel configuration of hybrid ABR for the treatment of thin stillage was evaluated. The hybrid ABR achieved the chemical oxygen demand (COD) removal, sulfate removal and methane yield of 97-94%, 94-97% and 294-310 mL CH4 g-1 CODremoved, respectively at organic loading rate (OLR) of 1-3.5 kg COD m-3 d-1. On the other hand, the value of COD and sulfate removal and methane yield for the conventional ABR were 75-94%, 67-76% and 140-240 mL CH4 g-1 CODremoved, respectively at OLR range of 1.1-1.8 kg COD m-3 d-1. The enhanced performance and robustness of the novel ABR was demonstrated to be the result of incorporation of solid/liquid/gas separators into the configuration of the conventional ABR, leading to reduced biomass washout, higher solid retention time and significantly improved phase separation.

Removal of pharmaceutical compounds in water and wastewater using fungal oxidoreductase enzymes.

Due to recalcitrance of some pharmaceutically active compounds (PhACs), conventional wastewater treatment is not able to remove them effectively. Therefore, their occurrence in surface water and potential environmental impact has raised serious global concern. Biological transformation of these contaminants using white-rot fungi (WRF) and their oxidoreductase enzymes has been proposed as a low cost and environmentally friendly solution for water treatment. The removal performance of PhACs by a fungal culture is dependent on several factors, such as fungal species, the secreted enzymes, molecular structure of target compounds, culture medium composition, etc. In recent 20 years, numerous researchers tried to elucidate the removal mechanisms and the effects of important operational parameters such as temperature and pH on the enzymatic treatment of PhACs. This review summarizes and analyzes the studies performed on PhACs removal from spiked pure water and real wastewaters using oxidoreductase enzymes and the data related to degradation efficiencies of the most studied compounds. The review also offers an insight into enzymes immobilization, fungal reactors, mediators, degradation mechanisms and transformation products (TPs) of PhACs. In brief, higher hydrophobicity and having electron-donating groups, such as amine and hydroxyl in molecular structure leads to more effective degradation of PhACs by fungal cultures. For recalcitrant compounds, using redox mediators, such as syringaldehyde increases the degradation efficiency, however they may cause toxicity in the effluent and deactivate the enzyme. Immobilization of enzymes on supports can enhance the performance of enzyme in terms of reusability and stability. However, the immobilization strategy should be carefully selected to reduce the cost and enable regeneration. Still, further studies are needed to elucidate the mechanisms involved in enzymatic degradation and the toxicity levels of TPs and also to optimize the whole treatment strategy to have economical and technical competitiveness.

A novel process for preparation of fatty acid oil mixture in solid form.

The present study describes a novel and scalable process for preparation of omega-3 and omega-6 fatty acids in solid form. The process involves multiple steps consisting of combining the oil with a metal base in alcohol to form a solution, followed by addition of reaction mixture to acetonitrile (anti-solvent) to form a slurry and further separating the solid through filtration. This process results in formation of a flowable solid with yield of 44-76% depending on the procedure employed. The fatty acid profile of the calcium and magnesium salts was stable after one year of storage in ambient conditions. The type of solvent and anti-solvent employed in such process has tremendous effect on the resulting solid texture, which could range from complete gum to a workable, filterable solid. It was also demonstrated that increasing the concentration of base in alcohol reduces the amount of residual acetonitrile in the solid.

Immobilized laccase on oxygen functionalized nanobiochars through mineral acids treatment for removal of carbamazepine.

Biocatalytic treatment with oxidoreductase enzymes, especially laccases are an environmentally benign method for biodegradation of pharmaceutical compounds, such as carbamazepine to less harmful compounds. However, enzymes are required to be immobilized on supports to be reusable and maintain their activity. Functionalization of support prior to immobilization of enzyme is highly important because of biomolecule-support interface on enzyme activity and stability. In this work, the effect of oxidation of nanobiochar, a carbonaceous material produced by biomass pyrolysis, using HCl, H2SO4, HNO3 and their mixtures on immobilization of laccase has been studied. Scanning electron microscopy indicated that the structure of nanobiochars remained intact after oxidation and Fourier transform infrared spectroscopy confirmed the formation of carboxylic groups because of acid treatment. Titration measurements showed that the sample treated with H2SO4/HNO3 (50:50, v/v) had the highest number of carboxylic groups (4.7mmol/g) and consequently the highest efficiency for laccase immobilization. Additionally, it was observed that the storage, pH and thermal stability of immobilized laccase on functionalized nanobiochar was improved compared to free laccase showing its potential for continuous applications. The reusability tests towards oxidation of 2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) showed that the immobilized laccase preserved 70% of the initial activity after 3cycles. Finally, using immobilized laccase for degradation of carbamazepine exhibited 83% and 86% removal in spiked water and secondary effluent, respectively.