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To fully harness the potential of laccase in the efficient decolorization and detoxification of single and mixed dyes with diverse chemical structures, we carried out a systematic study on the decolorization and detoxification of single and mixed dyes using a crude laccase preparation obtained from a white-rot fungus strain, Pleurotus eryngii. The crude laccase preparation showed efficient decolorization of azo, anthraquinone, triphenylmethane, and indigo dyes, and the reaction rate constants followed the order Remazol Brilliant Blue R > Bromophenol blue > Indigo carmine > New Coccine > Reactive Blue 4 > Reactive Black 5 > Acid Orange 7 > Methyl green. This laccase preparation exhibited notable tolerance to SO[sub.4] [sup.2−] salts such as MnSO[sub.4], MgSO[sub.4], ZnSO[sub.4], Na[sub.2]SO[sub.4], K[sub.2]SO[sub.4], and CdSO[sub.4] during the decolorization of various types of dyes, but was significantly inhibited by Cl[sup.−] salts. Additionally, this laccase preparation demonstrated strong tolerance to some organic solvents such as glycerol, ethylene glycol, propanediol, and butanediol. The crude laccase preparation demonstrated the efficient decolorization of dye mixtures, including azo + azo, azo + anthraquinone, azo + triphenylmethane, anthraquinone + indigo, anthraquinone + triphenylmethane, and indigo + triphenylmethane dyes. The decolorization kinetics of mixed dyes provided preliminary insight into the interactions between dyes in the decolorization process of mixed dyes, and the underlying reasons and mechanisms were discussed. Importantly, the crude laccase from Pleurotus eryngii showed efficient repeated-batch decolorization of single-, two-, and four-dye mixtures. This crude laccase demonstrated high stability and reusability in repeated-batch decolorization. Furthermore, this crude laccase was efficient in the detoxification of different types of single dyes and mixed dyes containing different types of dyes, and the phytotoxicity of decolorized dyes (single and mixed dyes) was significantly reduced. The crude laccase efficiently eliminated phytotoxicity associated with single and mixed dyes. Consequently, the crude laccase from Pleurotus eryngii offers significant potential for practical applications in the efficient decolorization and management of single and mixed dye pollutants with different chemical structures.

A spherical CuO-Bi[sub.2]O[sub.3]-MgO/SiO[sub.2] catalyst was prepared using the coprecipitation-gel method. The study investigated the influence of the MgO/SiO[sub.2] ratio on the catalyst structure and the activity of the catalyst in the preparation of 1,4-butanediol from formaldehyde acetylenation. The activity and filtration performance of the catalyst were compared with commercial samples. The study found that different MgO/SiO[sub.2] ratios not only changed the size of CuO particles, the orientation of crystal faces, the specific surface area, and the pore distribution in the catalyst, but also adjusted the interaction between CuO and SiO[sub.2]. In addition, different MgO/SiO[sub.2] ratios could significantly alter the structure of the catalyst and enhance its activity, with the highest activity achieved when the MgO/SiO[sub.2] ratio was 1:3. Experimental results showed that the spherical CuO-Bi[sub.2]O[sub.3]-MgO/SiO[sub.2] catalyst in this study achieved a selectivity of 96.3% and a conversion rate of 94.0% when reacting with formaldehyde at a concentration of 38 wt% for 12 h. The catalyst outperformed commercial samples in terms of activity and had the same strength level and better filtration separation performance as commercial samples.

C. vulgaris microalgae biomass was employed for the extraction of valuable bioactive compounds with deep eutectic-based solvents (DESs). Particularly, the Choline Chloride (ChCl) based DESs, ChCl:1,2 butanediol (1:4), ChCl:ethylene glycol (1:2), and ChCl:glycerol (1:2) mixed with water at 70/30 w/w ratio were used for that purpose. The extracts’ total carotenoid (TCC) and phenolic contents (TPC), as well as their antioxidant activity (IC50), were determined within the process of identification of the most efficient solvent. This screening procedure revealed ChCl:1,2 butanediol (1:4)/H[sub.2]O 70/30 w/w as the most compelling solvent; thus, it was employed thereafter for the extraction process optimization. Three extraction parameters, i.e., solvent-to-biomass ratio, temperature, and time were studied regarding their impact on the extract’s TCC, TPC, and IC50. For the experimental design and process optimization, the statistical tool Response Surface Methodology was used. The resulting models’ predictive capacity was confirmed experimentally by carrying out two additional extractions under conditions different from the experimental design.

3-Hydroxybutanone (Acetoin, AC) and 2,3-butanediol (BD) are two essential four-carbon platform compounds with numerous pharmaceutical and chemical synthesis applications. AC and BD have two and three stereoisomers, respectively, while the application of the single isomer product in chemical synthesis is superior. AC and BD are glucose overflow metabolites produced by biological fermentation from a variety of microorganisms. However, the AC or BD produced by microorganisms using glucose is typically a mixture of various stereoisomers. This was discovered to be due to the simultaneous presence of multiple butanediol dehydrogenases (BDHs) in microorganisms, and AC and BD can be interconverted under BDH catalysis. In this paper, beginning with the synthesis pathways of microbial AC and BD, we review in detail the studies on the formation mechanisms of different stereoisomers of AC and BD, summarize the properties of different types of BDH that have been tabulated, and analyze the structural characteristics and affinities of different types of BDH by comparing them using literature and biological database data. Using microorganisms, recent research on the production of optically pure AC or BD was also reviewed. Limiting factors and possible solutions for chiral AC and BD production are discussed.

Poly(butylene adipate-co-terephthalate) (PBAT), a polyester made of terephthalic acid (TPA), 1,4-butanediol, and adipic acid, is extensively utilized in plastic production and has accumulated globally as environmental waste. Biodegradation is an attractive strategy to manage PBAT, but an effective PBAT-degrading enzyme is required. Here, we demonstrate that cutinases are highly potent enzymes that can completely decompose PBAT films in 48 h. We further show that the engineered cutinases, by applying a double mutation strategy to render a more flexible substrate-binding pocket exhibit higher decomposition rates. Notably, these variants produce TPA as a major end-product, which is beneficial feature for the future recycling economy. The crystal structures of wild type and double mutation of a cutinase from Thermobifida fusca in complex with a substrate analogue are also solved, elucidating their substrate-binding modes. These structural and biochemical analyses enable us to propose the mechanism of cutinase-mediated PBAT degradation. Bio-degradation of poly(butylene adipate-co-terephthalate) is an attractive tactic but requires an effective hydrolytic enzyme. Here, the authors demonstrate that cutinases are highly potent PBAT-decomposing enzymes and their mechanism is proposed based on substrate-binding mode.

This research work used Musa paradisiaca(banana) peels as a natural solvent, assorted with the precursor AgN[O.sub.3] (10 mM) to perform the green synthesis of silver nanoparticles. The phytochemical components present in the Musa paradisiaca peel extracts were determined by gas chromatography coupled to a mass spectrometer (GC-MS), and it was possible to identify the compounds: 1.2 Ethanediol (60.0261 %) and 2.3 Butanediol (11.2%); these -diols represent a highly reducing agent for metals, since they act as a solvent for the metal precursor behaving as a reducing agent, and facilitating the formation of nanoparticles. Likewise, the synthesized silver nanoparticles were subjected to a washing and drying treatment to be subsequently characterized by means of UV-Vis and XRD techniques, resulting in a wavelength of 411 nm, which is characteristic of these metallic nanoparticles, and achieving the identification of the face-centered cubic structure (fcc) of the metallic silver, with an average particle size of 21.8 nm according to the Debye-Scherrer equation.

2-Hydroxytetrahydrofuran (HTHF) is the main by-product of hydrogenation of 1,4-butynediol (BYD) to 1,4-butanediol (BDO) in industry, which is difficult to be effectively removed in the subsequent distillation process and seriously affects the product quality. Here, a series of silica-supported bimetallic Ni-Fe catalysts with different Fe/Ni weight ratios were prepared by using incipient wetness impregnation method and investigated the effect of Fe on the catalyst performance in the hydrogenation of HTHF to BDO. In comparison with monometallic Ni and Fe catalysts, bimetallic Ni-Fe catalysts exhibited better performance for HTHF hydrogenation due to the formation of Ni-Fe alloy phase identified by XRD, TEM, STEM-EDS, H.sub.2-TPR, NH.sub.3/H.sub.2-TPD, Pyridine FTIR and XPS, etc. A mechanism is proposed to explain the promoting effect of Fe, which can be assigned to the synergism between nickel sites with high ability to activate/overflow hydrogen and Fe-containing sites with strong oxophilicity for the activation of the O-C-O bond over the tetrahydrofuran ring.

Using biodegradable instead of conventional plastics in agricultural applications promises to help overcome plastic pollution of agricultural soils. However, analytical limitations impede our understanding of plastic biodegradation in soils. Utilizing stable carbon isotope ( 13 C-)labelled poly(butylene succinate) (PBS), a synthetic polyester, we herein present an analytical approach to continuously quantify PBS mineralization to 13 CO 2 during soil incubations and, thereafter, to determine non-mineralized PBS-derived 13 C remaining in the soil. We demonstrate extensive PBS mineralization (65 % of added 13 C) and a closed mass balance on PBS− 13 C over 425 days of incubation. Extraction of residual PBS from soils combined with kinetic modeling of the biodegradation data and results from monomer (i.e., butanediol and succinate) mineralization experiments suggest that PBS hydrolytic breakdown controlled the overall PBS biodegradation rate. Beyond PBS biodegradation in soil, the presented methodology is broadly applicable to investigate biodegradation of other biodegradable polymers in various receiving environments. This study applies stable carbon isotope labelling to study polymer biodegradation in soils. This labelling enables accurate and precise tracking of polymer carbon during biodegradation and, thereby, provides a holistic picture of this process.

The photocatalytic conversion of ethanol and the simultaneous development of hydrogen technology play a role in solving the energy crisis and reducing environmental pollution. In this research, rod-like M-MoS[sub.2] serves as a channel for charge transfer, leading to superior photocatalytic activity compared to H-MoS[sub.2]. Further, two-dimensional (2D) B-doped C[sub.3]N[sub.4] (BCN) nanosheets were anchored on the one-dimensional (1D) rod-like M-MoS[sub.2] surface to form a 1D/2D heterojunction, with M-MoS[sub.2]/BCN-0.08 (mass ratio of M-MoS[sub.2]:BCN of 0.08:1) exhibiting the highest photocatalytic performance. Under visible light irradiation, the ethanol conversion rate reached 1.79% after 5 h of photocatalytic reaction per gram of catalyst, while generating 421 μmol of 2,3-butanediol (2,3-BDO), 5460 μmol of acetaldehyde (AA), and 5410 μmol of hydrogen gas (H[sub.2]). This different characterization provides evidence that a significant amount of photoinduced electrons generated in BCN under illumination conditions rapidly transfer to the conduction band (CB) of M-MoS[sub.2] through the rod-like structure of M-MoS[sub.2], and finally transfer to Pt to promote the production of hydrogen gas. The photoinduced holes in the valence band (VB) of M-MoS[sub.2] are rapidly consumed by ethanol upon transferring to BCN, effectively separating the photoinduced electron–hole pairs and resulting in superior photocatalytic performance.