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Abstract Superwetting aerogel is a promising alternative for the remediation of emulsified oily wastewater for its high porosity combined with extreme wettability enabled high separation performances to emulsion wastewater. However, it remains challenging for superwetting aerogels to accomplish high-performance dual separation to surfactant-stabilized oil-in-water (O/W) and water-in-oil (W/O) emulsions with high stability. Herein, an environmentally benign superamphiphilic composite aerogel was prepared by a green synthesis route that relied on the utilization of natural amphiphilic biomass. Collagen fibers (CFs) were utilized to construct the three-dimensional (3D) supramolecular skeleton of aerogel to provide high storage capacity of water/oil and outstanding capillary effect to boost the mass transfer. The two-dimensional (2D) lamellar structure of gelatin (Gel) was further grown on the skeleton of CFs aerogel to play the role for simultaneously enhanced demulsifying capability and spreading of emulsions. The as-prepared superamphiphilic aerogel enabled the separation of highly stable surfactant-stabilized O/W and W/O emulsions with high separation efficiency and flux. Excellent recycling performances and anti-fouling performance were also confirmed. Our investigations therefore demonstrated that the structural engineering of superamphiphilic aerogel is a promising way to realize high-performance dual separation of surfactant-stabilized O/W and W/O emulsion wastewater. Graphical Abstract

Abstract Melamine resin (MR), traditionally synthesized using melamine and formaldehyde, is widely used in the leather industry. However, the emission of free formaldehyde poses a significant challenge for conventional MR. To address the issues of aldehyde in MR, extensive research has been conducted. This paper introduces a novel aldehyde-free MR (LTSL) retanning agent synthesized using cyanuric chloride, l-lysine, and sodium sulfanilate. The chemical structure of LTSL was analyzed via Fourier transform infrared spectroscopy, nuclear magnetic resonance, and X-ray photoelectron spectroscopy. The presence of amino, carboxyl, and sulfonic acid groups in LTSL enhanced its storability and imparted LTSL with an amphoteric character. The isoelectric point of LTSL was optimized to reach 4.37, and LTSL exhibited an appropriate size distribution with an average particle size of 254.17 nm and achieved high absorption rates of 87.77% and 95.84% for retanning and fatliquoring agents, respectively. Consequently, the thickness rate of LTSL reached up to 37%, with no detectable formaldehyde. Notably, LTSL also demonstrated excellent physical and mechanical properties, primarily attributed to the coordination and electrostatic interactions between the chrome-tanned collagen fiber and amino/carboxyl groups in LTSL. This research presents an innovative approach for developing an aldehyde-free MR retanning agent, significantly contributing to the sustainable development of leather manufacturing. Graphical Abstract

The interactions between lignin oligomers and solvents determine the behaviors of lignin oligomers self-assembling into uniform lignin nanoparticles (LNPs). Herein, several alcohol solvents, which readily interact with the lignin oligomers, were adopted to study their effects during solvent shifting process for LNPs’ production. The lignin oligomers with widely distributed molecular weight and abundant guaiacyl units were extracted from wood waste (mainly consists of pine wood), exerting outstanding self-assembly capability. Uniform and spherical LNPs were generated in H2O-n-propanol cosolvent, whereas irregular LNPs were obtained in H2O-methanol cosolvent. The unsatisfactory self-assembly performance of the lignin oligomers in H2O-methanol cosolvent could be attributed to two aspects. On one hand, for the initial dissolution state, the distinguishing Hansen solubility parameter and polarity between methanol solvent and lignin oligomers resulted in the poor dispersion of the lignin oligomers. On the other hand, strong hydrogen bonds between methanol solvent and lignin oligomers during solvent shifting process, hindered the interactions among the lignin oligomers for self-assembly.

Despite lignin nanoparticles (LNPs) being extensively employed as assistant agents to improve the UV-blocking performance of sunscreens, there is a lack of information addressing how and to what extent the chemical and structural features of these particles relate to the improvements observed in the Sun Protection Factors (SPF) of the sunscreens. In this study, lignin oligomers were prepared by a solvothermal extraction process of five typical biomasses in a water–acetone co-solvent without noticeable degradation of the cellulose fraction. Afterward, LNPs were produced from the self-assembly of these lignin oligomers via the solvent-shifting methodology. When incorporated into the sunscreen, these had different morphologies, and exerted different UV-blocking capacities. The effects of the chemical structure and size distribution of the LNPs were systematically studied and compared to those of the original lignin oligomers. LNPs exhibited better UV-blocking ability than soluble lignin oligomers due to the more exposed chromophore on the surface. Besides, compact LNPs with conjugating CO and β-O-4 linkages, as well as the presence of the syringyl unit rich in the methoxyl group in the structures, were beneficial in boosting the UV resistance of the sunscreens. Even though smaller LNPs with higher surface area favored the UV shielding performance, LNPs with widely distributed sizes could further help decrease the UV transmittance. These findings provide an excellent basis for using lignin-derived materials as sunscreen additives and pave the way to developing new environmentally friendly materials for the cosmetic industry.

Abstract Compared with flavonoid glycosides, flavonoid aglycones are difficult to be separated since they have less hydroxyls. Collagen fiber (CF), a natural polymer, was once used as packing material for separation of kaempferol and quercetin (the typical flavonoid aglycones) after crosslinking by glutaraldehyde mainly based on hydrogen bonding and hydrophobic interaction in column length-diameter ratio of 60:1. Hydrophobic modification by grafting alkyl chains was then employed to enhance the hydrophobic interaction between CF and flavonoid aglycones, which can improve the separation efficiency and decrease column length-diameter ratio to 19:1. In order to further improve the adsorption capacity and separation efficiency, the strategy of simultaneously grafting hydrophobic alkyl chains (–CH2–CH2–) and alkali groups (–NH2) was adopted in this work to enhance hydrophobic interaction, hydrogen bonding and electrostatic association to flavonoid aglycones at the same time through grafting polyethyleneimine (PEI). PEI modified CF (PEI-CF) maintained the fiber structure of CF, and had higher adsorption extent and rate to flavonoid aglycones through the enhanced synergetic effect of hydrophobic interaction, hydrogen bonding and electrostatic association. As a result, PEI-CF presented a satisfactory column separation efficiency for kaempferol and quercetin even the length-diameter ratio of column was decreased to 11:1, which was much better than previously developed glutaradehyde-crosslinked collagen fiber and isobutyl-grafted collagen fiber, as well as commonly used polyamide and Sephadex LH-20. Graphical abstract

Abstract Protease-assisted soaking has received increasing attention in recent years. However, few reports have elaborated on the effect of bactericides, which are used to protect raw hides from microbial damage in the soaking process, on the performance of protease-assisted soaking. Here we investigate the effects of three bactericides, namely, 2-methyl-4-isothiazolin-3-one (MIT), sodium propyl 4-hydroxybenzoate (SPHB) and cetyl trimethyl ammonium bromide (CTAB), on the catalytic activity of protease. MIT and SPHB have little effect on the proteolytic activity, whilst CTAB has a negative effect. Fluorescence spectroscopy, synchronous fluorescence spectroscopy, molecular docking and molecular dynamics simulation were used to analyse the bactericide–protease interaction. The data reveal that MIT and SPHB are bound to the non-catalytic sites of protease, whilst CTAB affects the catalytic triad of protease. Furthermore, the protease and bactericides were used alone, simultaneously and sequentially in the soaking process, and their soaking performances were evaluated. The evaluation shows that the use of protease increases the microorganisms in the soaking float, and MIT exhibits the best bactericidal effect. The simultaneous use of protease and MIT effectively inhibits bacteria and scarcely affects the removal of unstructured proteins from hides and the attack on epidermis by protease. These findings contribute to a better understanding of the scientific use of protease with other auxiliaries in soaking. Graphical Abstract

Abstract Wet-salted skin, as a special artificial high-salt environment, is rich in protein, fat, collagen and other nutrient substrates, and is a rich resource of halotolerant and halophilic microorganisms. However, knowledge gaps regarding the microbial community structure and inter taxa associations of wet-salted skin are large. In this study, the spatiotemporal dynamics and community structure of microorganisms present on wet-salted goatskins were investigated using 16S rRNA gene amplicon sequencing and culturable technique. Alpha diversity analysis based on Sobs, Chao, Ace and Shannon indices revealed that microbial diversity on the wet-salted goatskins exhibited a trend of ‘down → up → down → flat’ with time. During preservation, genera belonging to the bacteria domain such as Acinetobacter, Weissella and Streptococcus were slowly dying out, whereas those belonging to halophilic archaea such as Natrialba and Haloterrigena were gradually flourishing. Moreover, to resist high-salt stress, microorganisms on the wet-salted goatskin gradually migrated from the outside to the inside, eventually leading to the microbial diversity inside the skin being the same as or even higher than that on the skin surface. Venn diagram analysis revealed that the strains of some genera, including Psychrobacter, Salimicrobium, Salinicola, Ornithinibacillus, Halomonas, Bacillus and Chromohalobacter, were distributed throughout the interior and exterior of the wet-salted goatskin and existed during various periods. Accordingly, 45 protease-producing halophilic or halotolerant microorganisms were isolated and screened from the wet-salted goatskin using the gradient dilution plate method. Importantly, 16S rRNA genes of some bacteria exhibited less than 99.5% similarity to valid published species, indicating that they likely are novel species and have a good potential for application. Graphical Abstract

Abstract The effect of hydrophobic modification on the performances of collagen fibers (CFs) was investigated by using silane coupling agents with different alkyl chains as hydrophobic modifiers. It was found silane could be easily grafted onto CF surface through covalent bonds under 5% water content. This modification led to the transformation of surface wettability of CF from hydrophilic to hydrophobic. Interestingly, the change of surface wettability resulted in substantial improvement of the modified CF properties, presenting well dispersity of collagen fibers, higher thermal stability and enhanced mechanical properties in comparison with natural CF. The degree of improvement mainly depended on the length of alkyl chain in silane. Longer alkyl chain produced strong hydrophobicity and subsequently more superior performances of the modified CF. When the length of alkyl chain increased to 18 carbon atoms, the modified CF possessed durable superhydrophobicity even exposed to aqueous solutions of different pH, UV, and organic solvents, and had excellent thermal and mechanical properties like leather fibers. In general, this work clearly revealed that the properties of CF are closely and positively related to the hydrophobicity, which is suggestive in developing new leather making technology. Graphical Abstract

Abstract Effect of retanning on the thermal stability of leather is eliciting increasing attention. However, the relationship between the hydrophilicity of retanning agents and the heat resistance of leather and the corresponding mechanism remain unclear. Herein, phenolic formaldehyde syntans (PFSs) were selected as models to explore the effect of the hydrophilicity of retanning agents on the thermal stability of retanned leather. The thermal stability of leather was closely correlated to the hydrophilic group content (sulfonation degree) of PFSs. As the sulfonation degree decreased, the water absorption rate of PFSs and their retanned leathers decreased, whereas the thermal stability of leather increased. Molecular dynamics simulation results proved that the introduction of PFSs could reduce the binding ability of collagen molecules with water and thus decreased the water molecules around the PFS-treated collagen. These results may provide guidance for the tanners to select retanning agents reasonably to improve the thermal stability of leather. Graphical Abstract

Abstract Gamma rays is widely used in modern science and technology, but it may cause health damage to practitioners. In the present study, natural composites based on leather and high-Z elements (atomic number ≥ 56) were fabricated and used as gamma rays shielding materials. These shielding materials were prepared by coating rare earth nanoparticles (Er2O3 or La2O3) onto the surface of natural leather, which was first impregnated with Bi3+ and Ba2+. Results show that the attenuation efficiency of the prepared Er1.31Bi5.46-NL (1.31 and 5.46 mmol cm−3 loaded elements) with thickness of 3.2 mm was 61.57% for incident rays at 121.78 keV (152Eu) and reached 96.4% in the incident of 59.5 keV (241Am), which is comparable to that of 0.25-mm lead plate (54.54 mmol cm−3). In addition, these natural-leather-based shielding materials exhibited low density (approximately 1/10 of Pb), high strength and wearable behaviors. Graphical abstract

Abstract Manufacture of eco-friendly chrome-free leather is of great significance for realizing sustainable development of leather industry. Conventional tanning theory believes that it is impossible to convert raw hide to leather without the utilization of cross-linking agent (e.g., chrome salts) among collagen fibers in raw hide. Here, we developed a brand-new leather manufacture strategy that relied on the composite dehydration media enabled self-driven directional dehydration mechanism to accomplish chrome-free leather manufacture for the first time, rather than followed the classic cross-linking mechanism that has been obeyed for more than one century in leather industry. We demonstrated that the essence of leather making is to regulate the water content in raw hide rather than to form cross-linkage among collagen fibers. The composite dehydration media comprised of anhydrous ethanol and molecular sieves (3A activated zeolite powder) successfully guaranteed continuous self-driven directional dehydration of raw hide by establishing stable water concentration gradient between raw hide and ethanol, which significantly increased the dispersity of collagen fibers in raw hide (with the water content reduced from 56.07% to 5.20%), thus obtaining chrome-free leather that is more ecological than chrome-tanned leather due to the elimination of any tanning agent. The as-prepared chrome-free leather exhibited outstanding tear force (174.86 N), tensile strength (24.56 N mm−2), elongation at break (53.28%) and dry-thermal stability, superior to chrome-tanned leather. Notably, the used composite dehydration media was recyclable for chrome-free leather manufacture, therefore facilitating an environmentally benign leather manufacture process. Our investigations are expected to open up a new conceptual leather making strategy that is applicable for realizing substantial manufacture of eco-friendly leather. Graphical abstract

Abstract The environmental impacts of typical fatliquors were diagnosed by the life cycle assessment of industrial production and use (post-tanning) processes. Life cycle impact assessment and sensitivity analysis showed that fatliquor and fatliquoring operation were the major contributors to the environmental impacts of post-tanning because a large amount of fatliquors was consumed during fatliquoring operation. The environmental impacts of fatliquors decreased in the following order: chlorinated paraffin (CP) > sulfonated rape oil (SNR) > sulfated rape oil (SR) > phosphated rape oil (PR) > oxidized–sulfited rape oil (OSR). Sulfuric acid, fuming sulfuric acid, and chlorine used for fatliquor modification gave the main contribution to most impact categories for SR, SNR, and CP production, whereas rape oil contributed the most for PR and OSR production. OSR use process reduced the primary energy demand, abiotic depletion potential, and global warming potential by 38.5%, 56.0%, and 48.5%, respectively, compared with CP use process. These results suggested that biomass-derived fatliquors, especially oxidized–sulfited and phosphate modified fatiliquors, helped reduce the environmental burdens in leather manufacturing. Graphical Abstract

Abstract Amphoteric polymer can be used as retanning agent in leather manufacture. It is particularly useful in chrome-free tanning systems since it can regulate the charge properties of chrome-free leather and enhance the fixation of anionic post-tanning chemicals in leather. However, the aggregation and precipitation of amphoteric polymer retanning agents around the isoelectric point (pI) hinder their wide application. Herein, we synthesized five amphoteric acrylic polymers (AAPs) by free radical copolymerization with acrylic acid and five different cationic acrylic monomers. The effect of cationic monomer structure on the aggregation behavior of AAPs was investigated. The aggregation of AAPs in aqueous solution showed pH and concentration dependence. Light scattering analysis showed that Poly (AA-co-MAPTAC) and Poly (AA-co-DMAPMA) were in the shape of coiled linear flexible chains with small particle size (Rg 7.6 nm and 14.8 nm, respectively) near the pI. However, Poly (AA-co-DAC), Poly (AA-co-DMC) and Poly (AA-co-DMAEMA) were in the shape of hollow spheres and exhibited serious aggregation. Quantum chemical calculations suggested that the amide groups in the cationic monomers MAPTAC and DMAPMA enhanced the nucleophilicity of AAPs. Thus the corresponding AAPs could carry a large number of cationic charges to slow their aggregation when the pH just climbed over the pI. The results are expected to provide theoretical reference for the synthesis and widespread application of AAPs.

Abstract It is well-known that the sulfonation degree (DS) of aromatic syntan is an important factor affecting its retanning performances. But the quantitative relation between DS and syntan property and the influencing mechanism of DS on syntan property are not clarified. In this work, five phenolic formaldehyde syntans (PFSs) with the same polymerization degree but varying DS were prepared to investigate the effect of DS on the properties of syntan and crust leather. It was found that the absolute value of zeta potential and the particle size of PFS decreased with increasing DS in aqueous solution. Molecular dynamic simulation results proved that the DS of PFS was a major contributor to electrostatic interaction and hydrogen bonding in the PFS–water system and greatly affected the aggregation and dispersion of PFS in aqueous solution. The PFS with a low DS was prone to aggregate to large particles in aqueous solution because of low intermolecular electrostatic repulsion and less hydrogen bonds and therefore can be used to increase the thickness and tightness of leather. The PFS with a high DS presented a small particle size with more anionic groups in aqueous solution, thereby sharply decreasing the positive charge of leather surface and facilitating the penetration of the post-tanning agents into the leather. These results might be scientifically valid for rational molecular design of syntans and more productive use of syntans in leather making. Graphical Abstract

Abstract Fatliquor oxidation may give leather unpleasant odor, and excessive amounts of Cr(VI) and volatile organic compounds. The accurate evaluation and improvement of the oxidative stability of fatliquors are of great significance to high-quality leather manufacturing. We proposed a set of practical methods for evaluating the oxidative stability of fatliquors on the basis of oxidation induction time, change in iodine value (∆ IV), and change in acid value (∆ AV) under accelerated oxidation conditions (at 100 °C with 10 L/h of air). Oxidation induction time is a highly sensitive marker for quantifying the oxidative stability of fatliquors, and ∆ IV and ∆ AV that are low cost and easy to operate are useful in evaluating the oxidative stability of fatliquors when the oxidation induction time is less than 22 h. The number of double bonds in fatliquors is an important factor affecting oxidative stability. The sulfation modification of fatliquors that greatly reduces double bonds and the addition of antioxidants, especially butylated hydroxyanisole and butylated hydroxytoluene, markedly improve oxidative stability of fatliquors.

Abstract This study demonstrated the interaction mechanism of collagen peptides (CPs) with 4-ethylphenol (4-EP), phenol, guaiacol, and 4-ethylguaiacol (4-EG) in the ethanol-water solution. The ultraviolet visible spectroscopy, zeta potential tests and hydrogen nuclear magnetic spectroscopy manifested that CPs interacted with the phenolic compounds. Meanwhile, Isothermal titration calorimetry determination indicated that the CPs was hydrogen bonded with 4-EP in 52 %(v/v) ethanol-water solution, while the hydrophobic forces played a major role in the interaction of CPs with guaiacol and 4-EG, respectively. Moreover, hydrogen and hydrophobic bonds were involved in the interaction between CPs and phenol. Finally, Head Space-solid Phase Microextraction Gas Chromatography Mass Spectrometry analysis indicated that the content of phenolic compounds in model solution efficiently decreased with the presence of CPs. In the real liquor, it was found that the content of volatile compounds (including phenolic compounds) was obviously decreased after CPs added.

Abstract Effective and ecofriendly converting biomass to chemicals is important for sustainable engineering based on the foreseeable shortage of fossil resources. Undecylprodigiosin (UP) is a promising antibiotic, but the direct feeding of pure precursor amino acids makes it costly for large-scale production. Here, collagen peptide (CP), a renewable animal-derived biomass contains abundant precursor amino acids of UP. CP can act as carbon and nitrogen source for the growth of Streptomyces coelicolor CGMCC 4.7172. The plant biomasses including soybean meal, wheat bran, and malt extract were unsuitable for UP prodution. However, 365.40 µg/L UP was detected after 24 h in the media containing CP, and its highest concentration reached 1198.01 µg/L. UP was also detected in the media containing meat hydrolysates of domestic animals, but its initial production time was delayed, and final concentration was lower than that in the medium containing CP only. Compared the fermentation performances of CP and other proteins, CP has a special superiority for UP production. These results revealed that UP biosynthesis may be dependent on amino acid availability of substrates and CP is beneficial for UP production because of its specific amino acid composition. Graphical abstract

Abstract Developing high-performance separation membrane with good durability is a highly desired while challenging issue. Herein, we reported the successful fabrication of chemically and mechanically durable superhydrophobic membrane that was prepared by embedding UiO-66 as size-sieving sites within the supramolecular fiber structure of collagen fiber membrane (CFM), followed by the polydimethylsiloxane (PDMS) coating. The as-prepared CFM/UiO-66(12)/PDMS membrane featured capillary effect-enhanced separation flux and homogeneous porous channels guaranteed high separation efficiency. When utilized as double-layer separation membranes, this new type of composite membranes separated various surfactant stabilized water-in-oil microemulsions and nanoemulsions, with the separation efficiency high up to 99.993 % and the flux as high as 973.3 L m− 2 h− 1. Compared with commercial polytetrafluoro ethylene (PTFE) membrane, the advantage of the double-layer CFM/UiO-66(12)/PDMS membranes in separation flux was evident, which exhibited one order of magnitude higher than that of commercial PTFE membrane. The CFM/UiO-66(12)/PDMS membrane was acid-alkali tolerant, UV-aging resistant and reusable for emulsion separation. Notably, the CFM/UiO-66(12)/PDMS membrane was mechanically durable against strong mechanical abrasion, which was still capable of separating diverse water-in-oil emulsions after the abrasion with sandpaper and assembled as double-layer separation membranes. We anticipate that the combination of CFM and metal organic frameworks (MOFs) is an effective strategy for fabricating high-performance separation membrane with high mechanical and chemical durability. Graphical Abstract

Abstract Dialdehyde sodium alginate (DSA) is an alternative chrome-free tanning material for fur production. To obtain satisfactory resultant fur and provide suggestions for the usage of DSA in fur making, the general properties of DSA tanned sheep fur were systematically investigated. The tanning mechanism of DSA was analyzed and it was verified that DSA was mainly combined with collagen fiber by forming Schiff base covalent bonds while supplemented by a small number of hydrogen bonds and ionic bonds. Due to the acid sensitivity of Schiff base structure, DSA tanned fur had poor resistance to acid rinsing but had excellent resistance to washing and good fatliquoring performance. Also, it had good resistances to yellowing and reductant. After being retanned by chrome tanning agent, the fur was capable of enduring a high-temperature dyeing process (68 °C for 8 h). Overall, DSA tanned sheep fur had favorable properties under appropriate post-tanning processing conditions to manufacture light-colored or dark-colored fur products with desirable physical properties. Graphical abstract

Abstract Collagen fiber (CF) and silane coupling agent-modified collagen fiber (MCF) were used as flame retardant filler for natural rubber (NR) modification. The combustion phenomena and properties of composites blended with different dosages of CF or MCF were compared to elucidate the flame retardant mechanism of the composites. The flame retardancy of NR can be enhanced effectively by increasing nitrogen content (the nitrogen content of CF is about 18%), creating air pockets, and structuring the flame retardant network in the composites. MCF failed to structure a flame retardant network in the composite, indicating that its modification effects of MCF are weaker than those of CF. When CF dosage was 30 wt%, the composite can achieve the best flame retardancy, with limited oxygen index of 29.4% and without smoke and dripping during burning. This study demonstrated a new method for the flame retardant modification of NR. Graphical abstract

Abstract A promising and practical chrome-free tanning system has been developed based on a novel Al–Zr bimetal complex tanning agent. However, to achieve satisfactory resultant leather, the retanning process that is compatible with this emerging tannage needs to be investigated systematically. This paper aims to explore the interaction between the bimetal complex tanned wet white and retanning agents. The isoelectric point (pI) of wet white was 7.2, which was nearly the same as wet blue. The electropositivity of wet white was even higher than that of wet blue during post-tanning processes, resulting in higher uptake rate of retanning agents. The distribution of various retanning agents in wet white was analyzed by pI measurement of layered leather and fluorescent tracing technique. The retanning agents were unevenly distributed throughout the cross-section, which might be an important restriction factor in obtaining satisfactory organoleptic properties of the crust leather. This fact is mainly due to the strong electrostatic interaction between anionic retanning agents and wet white. Applying a high dosage of multiple retanning agents in a proper sequence of addition benefited the full penetration of retanning agents in leather matrix and thus improved the organoleptic properties of crust leather. This work provides guidance for optimizing retanning process of the wet white leather. Graphical abstract

Alterations of epigenetic modulators are extensively associated with cancer, but their key molecular activities in cancer regulation are often unclear. We discovered that lysine demethylase 6A (KDM6A, also known as UTX) suppresses cancer by forming liquid-like condensates with lysine methyltransferase 2D (KMT2D, also known as MLL4) and regulating chromatin activity at multiple levels.

Abstract Bating pelt with protease is an important process, which removes unwanted non-collagenous proteins from the pelt and moderately disperse hide collagen network. However, the grain surface, may be excessively hydrolyzed during bating due to the longer retention time of protease in the grain than in the middle layer caused by the low mass transfer rate of protease in pelt. Here, the effects of protease dosage, common auxiliaries and molecular weight of protease on protease transfer during bating were investigated so that we can find the key points to avoid excessive collagen damage, particularly in the grain. Observably, increasing protease dosage led to faster protease transfer and softer leather, but along with more considerable grain damage. Using penetrating agent JFC (fatty alcohol-polyoxyethylene ether) and ammonium sulfate enhanced protease transfer and simultaneously alleviated collagen damage due to the decrease in interfacial tension and electrostatic attraction between protease and pelt, respectively. Additionally, proteases with lower molecular weight transferred faster in pelt, which suggests that a potential strategy to solve the conflict between the mass transfer and the reaction of protease in pelt might be to produce/employ smaller bating proteases. Graphical abstract

In the present investigation, an collagen fibre (CF), abundant natural biomass, was successfully grafted by polyethyleneimine (PEI). The resultant PEI grafted collagen fibre (CF-PEI) was employed as biocompatible and high cell loading support matrix for the immobilization of Saccharomyces cerevisiae cells. The as-prepared CF-PEI immobilized cells (CF-PEI-cell) exhibited high activity and stability for both batch and continuous fermentation. In batch fermentation, CF-PEI-cells showed enhanced stability as compared with other matrices supported cells, and produced an average ethanol concentration of 45.04 g/L with ethanol yield (YP/S) of 0.46 g/g and glucose conversion efficiency (η) of 90.4%. Continuous fermentation was operated stably in a down-flow trickling bed reactor charged with CF-PEI-cell for a total of 2 months. When the dilution rate was 0.16 1/h, the average ethanol productivity reached 7.18 g/(L h) with η of 88.94%. Further scanning electron microscopy observations confirmed that yeast cells can proliferate on the surface of CF-PEI during ethanol fermentation, which demonstrates that CF-PEI is indeed an ideal matrix for the immobilization of yeast cells.

Calcium aluminate clinkers, in which the mass ratio of Al2O3 to SiO2(A/S) is 5, were prepared at 1500℃ for 1h by proportioning pure reagents. The alumina leaching properties and crystal structure of 12CaO·7Al2O3 in the clinkers with different molar ratios of CaO unbonded with SiO2 to Al2O3 (C/A) were studied. The effect mechanism of C/A on the clinkers was also discussed by X-ray diffraction and X-ray fluorescence analysis. When C/A is 1.0 to 1.4, the alumina-leaching ratio improves because the amount of 12CaO·7Al2O3 increases with increasing C/A. When C/A is 1.4, the alumina-leaching ratio reaches the maximum value of 93.30%. In this case, 12CaO·7Al2O3 with defects forms, and the amount of substance of CaO is less than 11.3 mol. With the further increase of C/A, the alumina-leaching ratio decreases, which is because the preferred orientation of 12CaO·7Al2O3 changes from the (211) crystal plane into the (420) crystal plane.

Leather split, the byproduct of leather manufacture, possesses low utility value because it has loose weave of collagen fibers and weak mechanical strengths. Herein, a practical and convenient method for increasing strengths of leather split was developed by one-step in situ polymerization. The structures and properties of polyacrylate/leather split composites were systematically investigated. The results suggested the monomers with an α-methyl and a proper straight-chain ester group, such as nBMA, can effectively modify the leather split. For leather split with a thickness of 1.6 mm, the rational processes for preparation of polyacrylate/leather split composite are that monomer and split were stirred in a drum for 4 hours for full permeation and then the split was heated in anaerobic condition at 45°C for 30 min. The tensile strength, tear strength, and elongation at break of the optimized PnBMA/split composite were 18.72 MPa, 62.73 N/mm, and 46.02%, respectively. With these mechanical properties, the split after modification can be well used as leather for making shoes, bags, gloves, and clothing.

The golden Syrian hamster is the model of choice or the only rodent model for studying many human diseases. However, the lack of gene targeting tools in hamsters severely limits their use in biomedical research. Here, we report the first successful application of the CRISPR/Cas9 system to efficiently conduct gene targeting in hamsters. We designed five synthetic single-guide RNAs (sgRNAs)--three for targeting the coding sequences for different functional domains of the hamster STAT2 protein, one for KCNQ1, and one for PPP1R12C--and demonstrated that the CRISPR/Cas9 system is highly efficient in introducing site-specific mutations in hamster somatic cells. We then developed unique pronuclear (PN) and cytoplasmic injection protocols in hamsters and produced STAT2 knockout (KO) hamsters by injecting the sgRNA/Cas9, either in the form of plasmid or mRNA, targeting exon 4 of hamster STAT2. Among the produced hamsters, 14.3% and 88.9% harbored germline-transmitted STAT2 mutations from plasmid and mRNA injection, respectively. Notably, 10.4% of the animals produced from mRNA injection were biallelically targeted. This is the first success in conducting site-specific gene targeting in hamsters and can serve as the foundation for developing other genetically engineered hamster models for human disease.

AbstractPolygonati rhizoma (Huangjing in Chinese) is a common clinical tonic with the traditional effects of tonifying Qi, nourishing Yin. However, the lack of precise control of processing parameters has led to the uneven quality of processed Huangjing. A prediction model using the CRITIC method optimizes processing by correlating method, component contents, and biological activity, ensuring consistent quality and efficacy. [ABSTRACT FROM AUTHOR]

Efficient catalytic hydrogenation of lignin-based derivative vanillin (VAN) into valuable chemicals with a high selectivity is important yet challenging because of the lack of selective and active catalysts. Herein, a mixture of polyacrylonitrile (PAN) and water-insoluble tannin (Tan) was employed to create composite fibers through the electrospinning process, resulting in PAN-Tan composite fibers. The formation of hydrogen bonds between the -CN group of PAN and the phenolic -OH group of Tan proved advantageous for high dispersion and reduced physical entanglement, resulting in the production of thinner fibers. Leveraging abundant ortho-phenolic -OH groups of Tan, the PAN-Tan fibers were used to adsorb Pd2+ ions, which were reduced by in situ reduction process to Pd0 particles. Higher solute concentrations in the spinning solution improved the homogeneity of the electrospun PAN-Tan fibers, facilitating the dispersion and reduction of adsorbed Pd2+ on the fiber surface. Subsequently, these Pd/PAN-Tan fibers served as catalysts for the selective hydrogenation of the -CHO group of VAN to produce vanillyl alcohol (VAL) in an aqueous phase. Over 99% of VAN could be hydrogenated into VAL at 50 °C for 60 min under 0.5 MPa H2. Moreover, the catalyst exhibited universal applicability for the hydrogenation of diverse typical lignin-based aromatic aldehydes. The catalytic hydrogenation of VAN was then extended to a fixed-bed reactor for 24 h, and only VAL was detected in the effluent. Our study underscored the low energy consumption for catalyst preparation without additional reducing agents and high temperature carbonization process, the stability and reusability of the Pd/PAN-Tan fiber catalyst and its potential for large-scale industrial applications. [ABSTRACT FROM AUTHOR]