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Gold (Au) nanoparticles are widely adopted as nonbiological-toxic and biocompatible biomaterials. In this study, Au nanoparticles supported on lignin–tannin (LT) micro-/nanoparticles were prepared via a green and novel method without the use of an additional reducing agent. Soluble lignin oligomers and tannin were first obtained from H2O–tetrahydrofuran (THF) solvothermal treatment of the corncob residue and bayberry bark, which are industrial and forestry wastes of biomass, respectively. With outstanding self-assembly capability, the lignin oligomers induced the co-self-assembly of tannins into LT particles considerably, which enhanced the density of ortho-phenolic hydroxyls on the hydrophilic shell. Consequently, Au3+ can be stabilized and subsequently reduced into Au0 particles that were highly dispersed on the LT particles. Upon increasing the proportion of tannins, the amount of Au species on LT particles and the Au0/Aun+ ratio increased, accompanied by the inferior thermal stability of the particles. In addition, the as-prepared Au/LT particles can be taken up by cells and can reduce the vitality of several cancer cells, indicating a potential biotherapy application.

Penetration and reaction of tanning agents in leather greatly influence tanning performance and leather quality. Aldehyde tanning agents are widely used in leather manufacture, but their penetration and reaction in leather cannot be detected easily. Considering the fact that aldehyde can form a fluorescent Schiff base with amino groups of collagen, we visualized the distribution and reactivity of typical aldehyde tanning agents in leather during tanning process using a fluorescence microscope. The results showed that glutaraldehyde in leather was easily observed under the fluorescein isothiocyanate (FITC) filter system. The fluorescence intensity of pelt/leather gradually increased with penetrating of glutaraldehyde, basifying and heating, which was consistent with the formation of Schiff base and the increase in Ts of pelt/leather. Oxidized sodium alginate and dialdehyde sodium carboxymethyl cellulose in leathers were also detected using a fluorescence microscope because the aldehyde group of the two tanning agents formed a fluorescent Schiff base with amino groups of collagen. The oxazolidine tanned leather and the tetrakis hydroxymethyl phosphonium tanned leather emitted little fluorescence because they crosslinked collagen with hydroxymethyl group. These results indicate the fluorescent technique is useful to visualize the penetration and reaction of aldehyde tanning agents that crosslink collagen with aldehyde groups.

Storage is essential in improving the quality of strong‐flavor baijiu (SFB). Here, we investigated the release behaviors of metals from containers into SFB and their effects on the evolution of aroma compounds during storage. Twenty‐six metals were identified in SFB samples. The concentrations of Na, K, Ca, Mg, Al, and Fe obviously increased after storing in pottery jar, whereas those of Fe and Cu greatly increased after storing in stainless‐steel vessel. The volatility of most esters, alcohols, ketone, furan, and aldehyde decreased, whereas that of most acids increased after adding the metal ions into fresh SFB. The fluorescence intensity of SFB decreased with increased aging time in pottery jar, whereas the fluorescence intensity of acids was quenched with adding Fe3+ and Cu2+. All these results suggested that some metals released from containers had binding affinities with acids, thereby reducing SFB organoleptic stimulation by forming metal‐aroma compound complexes during storage., Some metals were dissolved out from containers such as pottery jar and stainless‐steel vessel into strong‐flavor baijiu (SFB) during storage. These metals had binding affinities with aroma compounds, thereby reducing SFB organoleptic stimulation by forming metal‐aroma compound complexes during storage.

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

This study is the first report on production and characterization of the enzyme from an Ornithinibacillus species. A 4.2-fold increase in the extracellular protease (called L9T) production from Ornithinibacillus caprae L9T was achieved through one factor at-a-time approach and response surface methodological optimization. L9T protease exhibited a unique protein band with a mass of 25.9 kDa upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis. This novel protease was active over a range of pH (4-13), temperatures (30-80 oC) and salt concentrations (0-220 g/L), with the maximal activity observed at pH 7, 70 oC and 20 g/L NaCl. Proteolytic activity was upgraded in the presence of Ag+, Ca2+ and Sr2+, but was totally suppressed by 5 mM phenylmethylsulfonyl fluoride which suggests that this enzyme belongs to the serine protease family. L9T protease was resistant to certain common organic solvents and surfactants; particularly, 5 mM Tween 20 and Tween 80 improved the activity by 63 and 15%, respectively. More importantly, L9T protease was found to be effective in dehairing of goatskins, cowhides and rabbit-skins without damaging the collagen fibers. These properties confirm the feasibility of L9T protease in industrial applications, especially in leather processing.

Trace anionic dyes in wastewater are difficult to be rapidly and efficiently removed because they are completely soluble and poorly biodegradable. Herein, a facile and environmentally friendly adsorbent was fabricated via the surface functioned SiO2 with abundant amine groups of polyethyleneimine (PEI). The structural characterization indicated that PEI was successfully immobilized on the SiO2 surface. The adsorption performance of SiO2-PEI was evaluated using acid orange II (AOII) as model pollutant. The adsorption of AOII on SiO2-PEI displayed high removal rates in the pH range of 2.0–9.0, and exhibited ultrafast removal (99.1% removal rate at 10 min). The adsorption behavior fitted well with the Langmuir isotherm and pseudo-second-order kinetic model, and the maximum uptake capability of AOII was higher than 705.3 mg/g. The excellent adsorption capacity of AOII on SiO2-PEI mainly relied on the electrostatic attraction between the sulfonic acid group of AOII and amine group of PEI in the adsorption process. Additionally, other anionic dyes like acid fuchsin and direct sky blue 5B could also be fast and efficiently removed by SiO2-PEI. This work is expected to open new possibilities for the ultrafast removal of anionic dye pollutants.

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

A novel hierarchically fibrous solid acid catalyst was facilely prepared by supporting Keggin-type phosphotungstic acid (HPW) on fibrous substrate of mesoporous TiO2-Al2O3 binary oxide nanofiber bundles. The acid strength and specific surface area were rationally tuned by changing the composition of TiO2-Al2O3 nanofiber bundles. When applied in fructose dehydration to prepare 5-hydroxymethylfurfural (5-HMF) using DMSO as the solvent, the fibrous HPW/TiO2-Al2O3 catalyst exhibited high catalytic activity (80.3%), selectivity (89.3%) and stability during the cycles. Our results demonstrated a promising and facile strategy for developing highly active and recyclable solid acid catalysts.

In this study, an extracellular metalloprotease (EMPr) from Bacillus sp. LCB14 was cloned, successfully expressed in Bacillus subtilis SCK6, and utilized to dehair goat skins in leather-making processes. Through optimization of fermentation conditions, the expression level of EMPr reached 6973 U/mL after 72 h of incubation. Then the crude enzyme was purified 6.30 fold through a three-step purification process of centrifugation, dialysis and SP Sepharose Fast Flow. The purified protease EMPr was established by 12.5% SDS-PAGE and showed 40.08 kDa. It exhibited highest activity 77,302 U/mg at pH 6.5 and 50 °C respectively. Protease activity was slightly enhanced by Li+ and K+. Interestingly, the protease activity was enhanced by the surfactants, such as, Tween 20, Tween 80, SDS, and Triton X-100 respectively. The dehairing experiments showed that the crude EMPr completely dehaired goatskins during 6 h at 33–35 °C without use of sodium sulfide. The enzymatic dehaired belt showed well opening up of fiber structure and the collagen was not damaged. Therefore the protease EMPr displayed great potential application in dehairing process without using sodium sulfide.

Sodium alginate (SA), tara gum (TG), starch (ST) and cyclodextrin (CD) were oxidized to dialdehyde polysaccharides (DAPs) using equivalent sodium periodate. The effects of polysaccharide structure features on aldehyde group content, molecular size and tanning performance of DAPs were investigated. Each DAP had abundant aldehyde groups (>7 mmol/g) for fur tanning in the experimental conditions, and DAP with higher aldehyde group content was obtained when polysaccharide with lower molecular weight and linear chain was used. Lower crystallinity and β-(1→4) glycosidic linkage of polysaccharide benefited its degradation. Compared with dialdehyde ST (Mw>150,000) and dialdehyde CD (Mw

An oligosaccharide-based masking agent suitable for chrome-free metal tanning was produced from cellulose via a stepwise degradation and oxidation process. Firstly, an AlCl3-NaCl-H2O/γ-valerolactone (GVL) biphasic solvent system was established for cellulose conversion (87.6%), which allowed in situ separation of the oligosaccharides and valuable small molecules into the two phases. Then, a H2O2 oxidation process enabled further degradation of the oligosaccharides and introduced –CHO/–COOH groups. This process strengthened the surface charge of the oligosaccharides, enhancing their coordination ability with metal ions. The post-oxidized fraction, together with added Zr species, exhibited satisfactory tanning performance, with a shrinkage temperature of 85.2 °C for the tanned leather. Al/Zr species could spontaneously coordinate with O atoms of O[double bond, length as m-dash]C(2) in the carboxylic group of post-oxidized oligosaccharides, which promoted the penetration of Al/Zr species into the leather matrix for efficient crosslinking reactions.

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

Chrome-free metal tanning agent has been considered as eco-friendly in the leather industry. However, extensive crosslinking reactions of metal species on the leather surface restrain their uniform penetration into the hierarchical nanoscale leather matrix. Thus, masking agents with appropriate coordination ability are needed. Herein, the selective degradation of hemicellulose in corncob was achieved with 92.5% of conversion in an AlCl3–H2O system, obtaining oligosaccharides masking agent with high purity and leaving cellulose and lignin in the solid residue for other valuable use. Subsequently, H2O2 oxidation was performed to introduce –CHO/–COOH into oligosaccharides and reduce their molecular weights, thereby enhancing coordination ability and reducing ligand dimension. The post-oxidized reaction fluids together with additional Zr species were subjected to leather tanning, in which the oligosaccharides could coordinate with Al/Zr species and promote the penetration of metal species into the leather matrix. By controlling the hemicellulose degradation and oligosaccharide oxidation, an appropriate concentration of oligosaccharides with proper –CHO/–COOH contents allowed the efficient masking effect of the oligosaccharides. As a result, a uniform distribution of Al/Zr species was observed on the cross section, and 83.5 °C of shrinkage temperature was obtained for the chrome-free tanned leather.

The kinetics and mechanisms of the oxidation of Cr(III) in soil contaminated by unsaturated oils were investigated. Batch experiments were performed with unsaturated oils, namely, fish oil, hydrogenated lard oil, rapeseed oil, and caster oil. Impacts of environmental parameters, including temperature, soil pH, UV irradiation, oil content, and soil moisture content were examined. Results showed that oxidation of Cr(III) in oil-treated soils was accompanied by the formation of Cr(VI), which first increased and then decreased. Changes in the peroxide values of oils and the production of hexanal in the soil indicated that hydroperoxide was closely related to the formation of Cr(VI). tert-Butylhydroperoxide, as a model molecule of hydroperoxide, significantly enhanced the oxidation of Cr(III) in water. This result further showed that hydroperoxides were responsible for the oxidation of Cr(III). Native soil substances, such as organic matter, Fe(II), and microbes, and the decomposition products of hydroperoxides, such as aldehydes, could reduce Cr(VI). The change in Cr(VI) content in the soil resulted from the competition between the oxidation of Cr(III) and the reduction of Cr(VI). High temperature, high soil pH, UV irradiation, and low soil moisture content could facilitate the oxidation of Cr(III), which is of environmental significance.

A novel Gram-stain-positive, motile, moderate halophile, strain L9T, was isolated from hides of white goat in China. The isolate grew optimally at 30 °C, at pH 7 and with 5–10% (w/v) NaCl. The predominant menaquinone was MK-7, and the major cellular fatty acids were identified as iso-C15:0 and anteiso-C15:0. The peptidoglycan amino acid type was determined to be A4β, containing l-ornithine and d-aspartic as diagnostic amino acids. The phospholipids were dominated by diphosphatidylglycerol, phosphatidylglycerol, one unidentified aminophospholipid and two unidentified phospholipids. Genome sequencing resulted in a genome size of 4.0 Mbp and a DNA G + C content of 35.9 mol%. Phylogenetic trees based on the 16S rRNA gene sequences showed the isolate to be closely related to Oceanobacillus limi H9BT (98.2% similarity) and Ornithinibacillus halophilus G8BT (97.5% similarity). The ANI and dDDH values between strain L9T and the closely related species were 69.8–76.1% and 13.0–20.5%, respectively. On the basis of the data presented, strain L9T represents a novel species of the genus Ornithinibacillus, for which the name Ornithinibacillus caprae sp. nov. is proposed. The type strain is L9T (= KCTC 43176T = CGMCC 1.17659T).

Carbonaceous materials have attracted considerable attention as promising catalysts of persulfate (PS) activation for antibiotic degradation. In this work, an environment-friendly and low-cost carbonaceous material (Cr2O3/BC) was prepared by pyrolyzing chrome shavings, and the catalytic ability of Cr2O3/BC for PS activation was evaluated using tetracycline (TC) as the model antibiotic. The Cr2O3/BC/PS system exhibited ultrafast TC removal efficiency (99.9% removal rate within 5 min), which was owing to persistent free radicals, defective sites, and dispersed Cr2O3 particles, which were beneficial for the generation of free radicals, such as OH·, SO4·-, ·O2– and 1O2. Coexisting substances, such as inorganic ions and humic acid, exerted little effect on TC removal. In addition, 99.9% of TC removal rates were achieved in TC contaminated tap water. Cr2O3/BC/PS system also exhibited the high removal rates towards ciprofloxacin (98% removal rate within 5 min) and sulfadiazine (99.8% removal rate within 5 min). Surprisingly, no chromium was detected after TC degradation, indicating that no secondary pollution was generated. This work provides a feasible strategy for the high-value use of chrome shavings and a practical method for antibiotic removal.

The corrosion inhibition behavior of commercial hydrolysable tannin (tara tannin), condensed tannin (black wattle tannin) and complex tannin (bayberry tannin) for mild steel in hydrochloric acid were investigated by means of gravimetric and electrochemical measurements. The inhibition efficiency increased with the increase of tannin concentration, and the inhibition performance of tannin followed hydrolysable tannin > complex tannin > condensed tannin. The pH of bulk solution has a significant impact on the inhibition behavior of tannin. Tannins exhibited high inhibition performance at low pH (0.3), but the corrosion rate slightly increased with a pH ≥ 2 for hydrolysable tannin and a pH > 3 for condensed tannin and complex tannin. Surface analysis revealed the formation of a protective compact inhibition film at pH 0.3, whereas a loose cracked film at pH 5.0 was revealed on the mild steel surface. The loose cracked film was deposition of ferric-tannates characterized by FTIR. Polarization experiments showed tannins act as mixed-type inhibitors with predominant anodic depression for hydrolysable tannin and cathodic depression for condensed tannin and complex tannin. EIS results indicated the increase of charge transfer resistance in the presence of tannins in 0.5 M HCl, supporting the formation of a protective film on a mild steel surface. Quantum chemical calculations predicted the higher inhibition performance of hydrolysable tannin based on the electronic properties of the molecular model. Molecular dynamic simulation revealed a nearly flat configuration for the hydrolysable tannin model molecule on a metal surface with more negative adsorption energies, as confirmed by the experiments.

The antioxidant activity in vivo and biological safety of a novel antioxidant peptide from bovine hair hydrolysates (BHP) were investigated. In various testing systems, BHP showed a strong capability to enhance the activities of antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px). Moreover, BHP led to a significant decrease of malondialdehyde (MDA) level in animal serums. All the results indicated that BHP (with a major sequence of Cys-Glu-Arg-Pro-Thr-Cys-Cys-Glu-His-Ser) had a remarkable antioxidant activity in vivo . Meanwhile, no mortalities or evidence of adverse effects was observed in Sprague-Dawley rats following acute oral gavage with BHP at a dose of 10 g/kg body weight during the acute toxicity test. Furthermore, the negative results obtained in Ames test, bone marrow micronucleus test and sperm malformation test demonstrated that BHP had no obvious genetic toxicity to cause mutagenicity of microorganism gene, chromosome and genital cells. All the results suggested that BHP possessed the remarkable antioxidant activity in vivo and biological safety, and therefore had the potential value to be safely utilized as a natural antioxidant agent applied in pharmaceutical, cosmetic and medicinal industries.

Dialdehyde carboxymethylcellulose (DCMC) solution generally has quite low solid content, which inevitably limits its industrial application. In this work, carboxymethylcellulose sodium (Na-CMC) was pre-degraded using H2O2 followed by periodate oxidation for preparing DCMC with high solid content as practical tanning agent. Pre-degradation conditions optimization showed that H2O2 dosage most impacted the tanning effect of DCMC, and the Mw and viscosity of Na-CMC underwent remarkable reduction. FT-IR and 1H NMR illustrated that aldehyde group was successfully introduced into DCMC after periodate oxidation. Under the optimized conditions, the solid content of DCMC could be improved to around 30%. This DCMC could endow tanned leather with high shrinkage temperature and satisfactory fiber dispersion. Besides, DCMC tanned leather had comparable physical and organoleptic properties to those of leathers tanned by chrome tanning agent and commercial polyaldehyde tanning agent TWT. This suggests the prospect of DCMC with high solid content as useful tanning agent.

Collagen fiber network (CFN) is a kind of supermolecule composed of collagen molecules with a hierarchical structure. As collagen fibers possess this kind of structure and a relatively high nitrogen content, they have the potential to be processed into an efficacious flame-retardant filler. To realize this potential, the dispersion and fixation of collagen fibers must be controlled effectively. In this study, a series of CFNs with collagen fiber dispersed to different extents and those fixed with different tanning agents were prepared. The fiber dispersion, limiting oxygen index (LOI), combustion performance, thermal stability, carbon residue morphology, carbon residue composition, and thermal conductivity of these CFNs were characterized. The results showed that the flame retardancy of the CFNs improved with an increase in dispersion extent of collagen fibers and removal of the interfibrillar substance. The CFN fixed with 4 wt% zirconium tanning agent (based on ZrO2) showed the best flame-retardant performance. Its LOI, total heat release, char yield at 800 °C and thermal conductivity were 62.3%, 15.51 MJ m−2, 18.33%, and 0.1362 W m−1 K−1, respectively. Because of these properties, this Zr-loaded CFN can be considered as a valuable flame retardant modifier for polymer materials.

A fluorescent fluorescent waterborne polyurethane (FWPU) was synthesized by conjugating fluorescer, isodium 4,4′-bis[4-anilino-6-hydroxyethylamino-6-(2-choloronilino-1,3,5-triazin-2-yl)amino]stilbene-2,2′-disulphonate (RSW), into polyurethane backbone as a chain extender. The expected structure of FWPU was confirmed by Fourier transform infrared, 1H nuclear magnetic resonance, and UV−vis spectrophotometer, and the effect of fluorescer content, temperature, as well as quencher on the fluorescence performances of FWPU was investigated in detail. Results reveal that covalently conjugation has unconspicuous effect on optical performance, and FWPU shows similar fluorescence intensity to fluorescer RSW except for a red shift of about 10 nm in maximum absorption wavelengths. Further study finds that there is a positive correlation between the concentration of fluorescer and the fluorescence intensity of FWPU; however, the opposite effect is obtained when the concentration exceeds 1 × 10−5 mol/L, which is attributed to the concentration self-quenching. Although high temperature will decrease the intensity of fluorescence, the fluorescence components in FWPU shows high resistance to fluorescence quencher and thermal decomposition as a consequence of chemical combination with the polymer chain.

With the evaluation of free radical scavenging activity, a novel antioxidant peptide (BHP) was isolated, purified and characterized from bovine hair. By using gel filtration chromatography (GFC) and high performance size exclusion chromatography (HPSEC), BHP was isolated and purified from bovine hair hydrolysates. Then, with the analysis of matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS), BHP was identified to be a novel peptide with a major sequence of Cys-Glu-Arg-Pro-Thr-Cys-Cys-Glu-His-Ser (CERPTCCEHS) and a molecular weight of 1325.4 Da, which was mainly composed by 13 kinds of amino acids. Meanwhile, BHP exhibited the remarkable antioxidant activity to scavenge free radicals (ABTS and hydroxyl radicals) and inhibit the erythrocyte hemolysis of rat blood and lipid peroxidation of rat liver effectively. Furthermore, BHP was observed to possess the significant antioxidant ability to protect DNA and PC12 cells against the oxidative injury induced by hydrogen peroxide. All results of present study suggested that the antioxidant peptide from bovine hair could be used as a potential antioxidant agent to protect human health applied in pharmaceutical and medical industries.

The effect of ultrasound on the activity of α-amylase, papain and pepsin was investigated and the mechanism of the effect was explored by determining their conformational changes. With the irradiation of power ultrasound, the activity of α-amylase and papain was inhibited, while the activity of pepsin was activated. According to the analysis of circular dichroism, Fourier transform infrared and fluorescence spectroscopy, the πo → π(∗) amide transitions and secondary structural components, especially β-sheet, of these three enzymes were significantly influenced by ultrasound. The tryptophan fluorescence intensity of the three enzymes was also observed to be affected by sonication. Furthermore, it was found that the pepsin molecule might gradually be resistant to prolonged ultrasonic treatment and recover from the ultrasound-induced damage to its original structure. The results suggested that the activity of α-amylase, papain and pepsin could be modified by ultrasonic treatment mainly due to the variation of their secondary and tertiary structures.

Collagen fibers, one of the most abundant biomass in the natural world, were used as the biomass template to synthesize cerium-doped mesoporous TiO2 nanofiber (SO42−–Cex/TiO2) solid acid catalysts. The physiochemical properties of the as-prepared catalysts were well characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), N2 adsorption–desorption isotherms, X-ray photoelectron spectroscopy (XPS). The fibrous morphology of native collagen fibers were found to be well preserved in SO42−–Cex/TiO2, and the acid strength and textural property of the SO42−–Cex/TiO2 were adjustable by changing the doping amount of Ce and the curing temperature. The catalytic properties of as-prepared catalysts were evaluated in the esterification reactions. It was found that the SO42−–Cex/TiO2 exhibited high activity under mild reaction conditions. When reacted at 90 °C for 45 min with a catalyst amount of 2 wt%, the conversion yields of ethyl acetate, butyl acetate, hexyl acetate and ethyl caproate were 99.9%, 97.06%, 94.29% and 86.75%, respectively. Additionally, the SO42−–Cex/TiO2 solid acid catalyst could be reused at least 6 times without significant loss of activity, exhibiting much better reusability as compared with the SO42−–TiO2* catalyst prepared by conventional approach.

DPY30 facilitates H3K4 methylation by directly binding to ASH2L in the SET1/MLL complexes and plays an important role in hematologic malignancies. However, the domain on DPY30 that regulates cancer growth is not evident, and the potential of pharmacologically targeting this chromatin modulator to inhibit cancer has not been explored. Here we have developed a peptide-based strategy to specifically target DPY30 activity. We have designed cell-penetrating peptides derived from ASH2L that can either bind to DPY30 or show defective or enhanced binding to DPY30. The DPY30-binding peptides specifically inhibit its activity in interacting with ASH2L and enhancing H3K4 methylation. Treatment with the DPY30-binding peptides significantly inhibited the growth of MLL-rearranged leukemia and other MYC-dependent hematologic cancer cells. We also revealed subsets of genes that may mediate the effect of the peptides on cancer cell growth, and showed that the DPY30-binding peptide sensitized leukemia to other types of epigenetic inhibitors. These results strongly support a critical role of the ASH2L-binding groove of DPY30 in promoting blood cancers, and demonstrate a proof-of-principle for the feasibility of pharmacologically targeting the ASH2L-binding groove of DPY30 for potential cancer inhibition.

The antioxidant activity and food protection effect of bioactive polypeptides from bovine hair were investigated. In various in vitro tests, polypeptides showed a strong reducing power and a remarkable antioxidant capability to scavenge free radicals (ABTS, superoxide and hydroxyl radicals). Moreover, polypeptides also exhibited a significant food protection effect to inhibit the oxidation of edible oil by controlling the peroxide value (POV). Furthermore, by using gel filtration chromatography (GFC), high performance size exclusion chromatography (HPSEC), amino acid analysis and atomic force microscopy (AFM), an antioxidant polypeptide (APB) was purified and characterized with a molecular weight of 18.7 KDa in the form of spherical lumps, which was composed of 17 kinds of amino acids and contained sulfydryl group. Our results suggested that the antioxidant polypeptide from bovine hair could be a new potential source for preparing natural antioxidant applied in oil or oil-rich food.

Pits are necessary solid bioreactors for the production of Chinese strong aromatic liquor, and the microbial community in these pits significantly affects the quality and yield of the liquor. In this study, the microbial community structures of different aged pit muds were evaluated by phospholipid fatty acid analysis. The results indicated that the microbial community was composed of bacteria, actinomycetes and fungi, with Gram-positive (G+) bacteria and anaerobic bacteria being dominant. The biomass of the pit mud increased and the microbial community shifted to G+ bacteria as the pit age increased. Principal component analysis showed that PC1 consisted mainly of fatty acids of saturated (15:0, 16:0 and 18:0), methyl-branched (a15:0, i16:0, a16:0, i17:0 and 8Me18:0), polyunsaturated (16:1ω7c, 16:1ω9) and cyclopropane (cy17:0 and cy19:0), and PC2 mainly of 18:1ω9, 18:1ω10 and a14:0, The characteristics of the microbial community structure in the pit mud resulted from the stress effects of low oxygen concentration, low pH and a high alcohol concentration. Copyright © 2013 The Institute of Brewing & Distilling

BACKGROUND Kaempferol, quercetin and myricetin are typical flavonols that are most concentrated in many medicinal herbs. However, the separation of these flavonols is very challenging due to their similar molecular structures. In the present investigation, the chromatographic separation of the flavonols kaempferol, quercetin and myricetin was performed using glutaraldehyde cross-linked collagen fibre (GCF) as the stationary phase. RESULTS Kaempferol, quercetin and myricetin could be completely separated from each other by the GCF column by using gradient elution with different solutions of aqueous ethanol (100% to 70%) and 50% acetone. When the chromatographic separation was carried out at a flow rate of 0.75 bed volume h−1 with a sample loading of 30 mg 7 g−1 GCF, the purity of kaempferol, quercetin and myricetin was 98.17%, 93.81% and 81.76%, respectively. The separation resolution was influenced by column length, flow rate and sample loading amount. The separation efficiency of GCF was not obviously reduced after applications had been repeated five times. In the fifth repeated application, the purity of the recovered kaempferol, quercetin and myricetin was still higher than 97%, 94% and 78%, respectively. CONCLUSION GCF is a promising adsorbent for use as a stationary phase in the chromatographic separation of flavonols from their mixtures. © 2012 Society of Chemical Industry

A series of Rh nanoparticles were prepared by using plant tannins as stabilizers. The as-prepared plant tannin-stabilized Rh nanoparticles were subsequently characterized by TEM, DES, FTIR and XPS. Due to the amphiphilic nature of plant tannins, the plant tannin-stabilized Rh nanoparticles were highly active in aqueous–organic biphasic hydrogenation of styrene. Furthermore, the as-prepared Rh catalyst can be reused 5 times without significant loss of catalytic activity, thus exhibiting a remarkable reusability.

A novel fibrous sulfated ZrO2 (SO42−/ZrO2) solid acid catalyst was prepared using collagen fiber as the template. The surface morphology of the as-prepared catalyst was observed by scanning electron microscopy (SEM), and the corresponding crystalline properties were determined by X-ray diffraction (XRD). To collect the structural properties of the SO42−/ZrO2 catalyst, N2 adsorption/desorption method was carried out. Temperature-programmed decomposition (TPD) of ammonia was conducted to determine the acid strength of the catalyst. It was found that the SO42−/ZrO2 catalyst had well-defined fibrous morphology and porous structure, which contained both medium strong acidic sites and strong acidic sites. Subsequently, the esterification of acetic acid with n-butanol was carried out to evaluate the catalytic activity and reusability of the SO42−/ZrO2 catalyst. The SO42−/ZrO2 catalyst exhibited high catalytic activity as compared with other solid acid catalysts. Furthermore, the catalyst can be reused 6 times without significant loss of catalytic activity, suggesting a satisfied reusability.

A new strategy was provided by the introduction of plant tannins in porous Al2O3 to solve the problems of thermal migration of Pd during catalyst preparation, which ensured the preparation of heterogeneous Pd catalysts with well dispersion and superior activity. Compared with the conventional Pd–Al2O3 catalyst, the as-prepared heterogeneous Pd catalyst exhibited considerably improved Pd dispersion, which was highly active for the catalytic hydrogenation of olefins.

A novel antifungal nano-silver agent (BT-CF-AgNPs) was synthesized by using bayberry tannin (BT) grafted collagen fiber (CF) as support, and the antifungal behaviors of the nano-silver were investigated by using Saccharomyces cerevisiae as a typical fungus. Bayberry tannin (BT), a kind of natural polyphenol, was grafted onto the CF surface to improve the loading capacity and control the size of the Ag nanoparticles. The main physical and chemical properties of this antifungal agent were characterized by means of Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Ultraviolet-visible Diffusion Reflection Spectrum (UV-DR), X-ray Diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS). It was found that this antifungal agent is in a highly ordered fibrous state. The average diameter of the Ag nanoparticles was 3.78 nm and the nanoparticles were well dispersed on BT-CF. Antifungal experiments demonstrated that BT-CF-AgNPs exhibited high antifungal activity. The number of living cells went down to zero when a cell suspension of S. cerevisiae (105 CFU/mL) was cultivated with BT-CF-AgNPs at 303 K for 14 h. The minimal inhibitory concentration (MIC) of BT-CF-AgNPs against S. cerevisiae was 12 μg Ag/mL. It was observed that the S. cerevisiae cells were damaged after being cultivated with BT-CF-AgNPs, accompanied by the formation of “pits” in the cell wall, while the accumulation of silver nanoparticles in the cell membrane results in the death of the cell. The present investigation indicated that BT-CF-AgNPs can be applied as a new type of antifungal material.

Molecular dynamics simulations were carried out to investigate the effect of pH on structure and stability of collagen-like peptide. All simulations were performed using the consistent valence force field (CVFF) molecular mechanical force field and isothermal-isobaric ensemble (NPT). The initial geometries of the collagen-like peptide were from an X-ray crystallographic structure. Some analyses from the molecular dynamics trajectories have been completed. The results show that the diameter of collagen-like peptide increases and the volume swells obviously in basic environment; however, the size of peptide changes slightly in acidic environment. The stability of collagen-like peptide decreases in acid and basic environment comparing to neutral environment based on root mean square deviation (RMSD). The number of hydrogen bond formed by peptide has a tendency to decrease in both acidic and basic environment. The average of intra-molecular H-bond is minimal under basic condition, and the average of inter-molecular H-bond between amino acid residues and water molecules is minimal under acid condition. The radial distribution function (RDF) shows that side-chain oxygen atoms are easier to form hydrogen bonds with water than side-chain nitrogen atoms. The interaction of various amino acid residues with water is position dependent. Distance between two triple helices increases markedly under highly basic condition, but changes slightly under highly acidic condition.

Thermo-sensitive polyurethane (TSPU) solution containing varying concentration of in situ-generated TiO2 nanoparticles was successfully prepared via an organic–inorganic hybrid technique, and the final nanocomposite membranes were formed via solution casting. Depending on the membrane formation temperature (Tmf) during casting, completely-opposite gas transport behaviors of the TSPU nanocomposite membranes were observed. When Tmf was lower than the melting point (Tm) of soft segment (PCL10000) in the TSPU, gas permeability coefficients of the nanocomposite membranes were found to increase significantly with increasing nano-TiO2 concentration. Conventional composite theory failed to explain such observation because filler particles are generally considered to create more tortuous diffusion path in the polymer for penetrants, and should thereby lead to a systematic reduction in gas permeability. This counter-intuitive phenomenon was then rationalized by postulating that rigid TSPU chain could not pack efficiently around the TiO2 nanoparticles during solvent evaporation, which resulted in polymer layer with higher free volume at the interface than the bulk polymer regions. Evidences supporting such presumption were provided by (1) density measurement that found negative deviation of actual densities of TSPU nanocomposite membranes from theoretical prediction; (2) positron annihilation lifetime spectroscopy that demonstrated increased free-volume size and concentration within TSPU upon the in situ generation of TiO2 nanoparticles. However, when Tmf was elevated above the Tm of the soft segment, flexible TSPU chain seemed able to pack around the TiO2 nanoparticles as efficiently as in the bulk polymer. In this case, gas transport behavior of the TSPU nanocomposite membranes followed the prediction of conventional composite theory.

The collagen-tannin resin (CTR), as a novel adsorbent, was prepared via a reaction of collagen with black wattle tannin and aldehyde, and its adsorption properties to Cu(II) were systematically investigated, including pH effect, adsorption equilibrium, adsorption kinetics, and column adsorption. The adsorption capacity of Cu(II) on CTR was pH-dependent, and it increased with the increase of solution pH. The adsorption isotherms were well described by Langmuir isotherm model with correlating constant (R2) higher than 0.99. The adsorption capacity determined at 303 K was high up to 0.26 mmol/g, which was close to the value (0.266 mmol/g) estimated from Langmuir equation. The adsorption capacity was increased with the increase of temperature, and thermodynamic calculations suggested that the adsorption of Cu(II) on CTR is an endothermic process. The adsorption kinetics were well fitted by the pseudo-second-order rate model. Further column studies suggested that CTR was effective for the removal of Cu(II) from solutions, and more than 99% of Cu(II) was desorbed from column using 0.1 mol/L HNO3 solution. The CTR column can be reused to adsorb Cu(II) without any loss of adsorption capacity.

Collagen-tannin resin (CTR), as a novel adsorbent, was prepared via reaction of collagen with black wattle tannin and aldehyde, and its adsorption properties to UO(2)(2+) were investigated in detail, including pH effect, adsorption kinetics, adsorption equilibrium and column adsorption kinetics. The adsorption of UO(2)(2+) on CTR was pH-dependent, and the optimal pH range was 5.0-6.0. CTR exhibited excellent adsorption capacity to UO(2)(2+). For instance, the adsorption capacity obtained at 303 K and pH 6.0 was as high as 0.91 mmol UO(2)(2+)/g when the initial concentration of UO(2)(2+) was 1.0 mmol/L. In kinetics studies, the adsorption equilibrium can be reached within 300 min, and the experimental data were well fitted by the pseudo-second-order rate model, and the equilibrium adsorption capacities calculated by the model were almost the same as those determined by experiments. The adsorption isotherms could be well described by the Freundlich equation with the correlation coefficients (R(2)) higher than 0.99, the adsorption behaviors of UO(2)(2+) on CTR column were investigated as well. Present study suggested that the CTR can be used for the adsorptive recovery of UO(2)(2+) from aqueous solutions.

A simple, rapid, and precise HPLC method was developed for the separation and quantification of catechins and caffeine in green tea extracts. Employing a Hypersil ODS C18 column (150 × 4.0 mm) and a diode UV detector (280 nm), it was found that a satisfactory separation can be achieved by a proper gradient elution using methanol and 0.2% acetonitrile solution. Five catechins (epigallocatechin (EGC), epigallocatechin gallate (EGCG), epicatechin (EC), gallocatechin gallate (GCG) and epicatechin gallate (ECG)) and caffeine in tea extracts were well separated on the chromatogram within 15 min. The method exhibited satisfactory repeatability (RSD ≤1.53%, n = 3) and accuracy (98.7%–102.4%, RSD ≤ 3.50%, n = 3), and reached a simultaneous determination of catechins and caffeine when used for a commercial sample of Chinese green tea extracts. This HPLC method might be suitable for the quality assurance of tea products and catechin-containing preparations.

BACKGROUND: Collagen fiber (CF) is a potential biopolymer support for preparing Pt nanoparticle catalyst. Previous work has shown that the interaction between CF and platinum group metals is not strong enough to fully immobilize these metals. Therefore, epigallocatechin-3-gallate (EGCG), which contains multiple orthophenolic hydroxyls, was grafted onto the surface of CF in order to enhance the immobilization of Pt nanoparticles on CF. The methods of preparing EGCG-grafted CF (EGCG-CF) and EGCG-CF supported Pt nanoparticle catalyst (Pt-EGCG-CF) were optimized. The catalytic activity and selectivity of Pt-EGCG-CF for hydrogenation of typical olefins were investigated. RESULTS: Scanning electron microscopy displayed the ordered fibrous morphology of Pt-EGCG-CF. The presence of EGCG grafted on the CF surface and the coordinate interaction of EGCG and Pt were confirmed by X-ray photoelectron spectroscopy analysis. X-ray diffraction and transmission electron microscopy analyses showed that Pt nanoparticles with diameter 1–3 nm were uniformly dispersed on the outer surface of CF. Hydrogenation of olefins catalyzed by Pt-EGCG-CF was conducted under mild conditions. This heterogeneous catalyst exhibited outstanding activity and nearly 100% selectivity for the hydrogenation of CC double bonds. Moreover, this catalyst presented satisfactory reusability and storage stability in air. CONCLUSION: An efficient method has been established to prepare a highly active, selective and stable Pt nanoparticle catalyst for the hydrogenation of olefins using EGCG-grafted CF as a bio-support. Copyright © 2009 Society of Chemical Industry

A novel collagen fiber adsorbent (CFA) was prepared by modification of natural collagen fiber using glutaraldehyde, and its adsorption behaviors to proanthocyanidins were investigated. Both batch and column adsorption experiments indicated that CFA has high adsorption selectivity to polymeric proanthocyanidins because of the stronger trend of these polymers to combine with collagen fiber through hydrophobic and hydrogen bonds. Based on this character of CFA, the purified oligomeric proanthocyanidins was obtained by using CFA as adsorbent. Meanwhile, it was found that the polymeric proanthocyanidins adsorbed on CFA can be easily desorbed by 50% (v/v) acetone-water solution. Thus, as a cost effective approach, CFA can be used to separate proanthocyanidins extracts into two parts, oligomeric proanthocyanidins and polymeric proanthocyanidins, which would favor the fine uses of proanthocyanidins extracts. Column adsorption studies showed that CFA used can be regenerated by using acetone-water solution...

A novel adsorbent, collagen immobilized tannin adsorbent (CITA), was prepared and its adsorption behaviors to Th(IV) were investigated. CITA was in fibrous state due to the reassembly of collagen molecules by the inducement of tannin. This adsorbent loaded a greater amount of tannin and exhibited higher adsorption capacity to Th(IV) than the tannin immobilized adsorbent prepared from collagen fiber. The adsorption of CITA to Th(IV) is mainly attributed to surface complexation, which is a pH- rather than an ionic strength-dependent process. The adsorption kinetics and isotherms were described by pseudo-second-order rate model and Freundlich equation, respectively. Column adsorption studies indicated that CITA is available for effectively recovering Th(IV) from aqueous solution.

A novel thermal-sensitive polyurethane (TSPU)/SiO 2 nano-hybrid membrane was prepared via in situ nano-hybrid method in wet phase inversion process, and used for water vapor permeation. Atom force microscope (AFM) and scanning electron microscope (SEM) were used to observe the size scale and the distribution of nano-SiO 2 throughout the TSPU matrix, and Fourier transform infrared (FTIR) spectroscopy was employed to reveal the nano-hybrid mechanism between TSPU and nano-SiO 2 . Simultaneously, differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analysis were used to investigate the phase separation behavior of the nano-composites and the influence of nano-SiO 2 on the crystallization of the TSPU. Results from AFM and SEM analysis show that the mean size and the distribution of nano-SiO 2 particles in the TSPU matrix is relied on the SiO 2 content, i.e. SiO 2 content lower than 5.0 wt% result in homogeneously dispersed nano-SiO 2 particles with a mean size below 100 nm approximately throughout the TSPU matrix, while obvious SiO 2 agglomerates (>1000 nm) are in the overwhelming majority with excessive addition of SiO 2 content into the TSPU resin. FTIR study indicates that two chemical bonds of Si–C and Si–O–C occur between the organic and the inorganic phase; one seems to be the reaction between nano-SiO 2 and H–Ar (aromatic ring), and another is the condensation reaction between Si–(OH) 4 produced by the hydrolysis of the nano-precursors (tetraethyoxyl silane) and the terminal HO–CH 2 – groups of the TSPU. Due to these interfacial interactions, the tensile strength and the broken elongation of nano-hybrid samples in the measurement of mechanical properties increase by 40.1% and 23.2%, respectively, as the SiO 2 content rises from 0.00 wt% to 5.0 wt%. DSC study reveals that nano-hybridization does not disrupt the intrinsic phase-separated structure of the TSPU, but the phase transition temperature of soft segment (defined as switch temperature, T s ) in TSPU increases slightly with the increase of nano-SiO 2 content. XRD analysis indicates that appropriate amount of nano-SiO 2 filled in the TSPU matrix is prone to induce the soft segment crystallization of the polymer. In addition, the water vapor permeability (WVP) of TSPU nano-hybrid membrane is found to depend on the size scale of SiO 2 particles, which is relied on SiO 2 content. To be specified, when nano-SiO 2 particles with an average size of 100 nm approximately are present in the TSPU matrix, the nano-hybrid samples show lower WVP at low temperatures and higher WVP at high temperatures than pure TSPU. Especially, when the temperature exceeds the T s , for example from 50 °C to 60 °C, the WVP of pure TSPU changes from 1026 g/m 2 day to 2200 g/m 2 day, whilst the WVP of the nano-hybrid TSPU with 5.0 wt% SiO 2 content changes from 995 g/m 2 day to 2927 g/m 2 day, the later shows more sensitive to thermal stimuli.

The size and shape of free-volume holes available in membrane materials control the rate of gas diffusion and its permeability. Based on this principle, two segmented thermo-sensitive polyurethane (TSPU) membranes with functional gates, i.e. the ability to sense and respond to external thermo-stimuli, were synthesized and used for water vapor controllable permeation. Differential scanning calorimetry (DSC), positron annihilation lifetimes (PAL), water swelling and water vapor permeability (WVP) were used to evaluate how the structure of the polyurethane (PU) and the temperature influence the free-volume holes size and the water vapor permeability (WVP) of the PU membranes. DSC study reveals that TSPU with a glass transition or a crystalline transition reversible phase shows an obvious phase-separated structure and a phase transition temperature (defined as switch temperature, Ts). PAL study indicates that the free-volume holes size of TSPU is closely related to the Ts. When the temperature is higher than the Ts, the ortho-positronium (o-Ps) lifetime (τ3) and the average radius (R) of free-volume holes of TSPU membrane increase dramatically. As a result, the WVP of TSPU membrane shows a dramatic increase. Additionally, the water swelling and the WVP of TSPU membrane are found to depend on the inner structure of the polymer, and they also give different responses to temperature variation. When the temperature is higher than the Ts, there is a significant increase of WVP from 3.80 kg/m2 day to 7.63 kg/m2 day for TSPU(a) and from 4.30 kg/m2 day to 8.58 kg/m2 day for TSPU(b), respectively. Phase transition accompanying significant changes in free-volume holes size and WVP can be used to develop “smart membranes” with functional gates and controllable gas permeation.

Pepsin-soluble collagen was extracted from the skin of grass carp ( Ctenopharyngodon idella ) with a yield of 46.6%, on a dry weight basis. Electrophoretic patterns showed that the collagen contained α1 and α2 chains, similar to those of calf skin collagen. The imino acid content of the collagen from grass carp skin was much lower than those of mammalian’s collagens, as also were the transition temperature and denaturation temperature which were only 24.6 °C and 28.4 °C respectively. Peptide maps of the collagen digested by trypsin and V8 protease showed different peptide fragments from those of calf skin collagen and other fish skin collagens, suggesting differences in amino acid sequences and collagen conformation. In addition, the lyophilized collagen sponge from grass carp skin had a uniform and regular network structure, just like calf skin collagen sponge. These results suggest that grass carp skin has potential for use as a supplementary source of collagen.

Tannins occur commonly in the wastewaters from forestry, plant medicine, paper and leather industries. The treatment of this kind of wastewaters, including settling and biodegradation, is usually difficult because tannins are highly soluble in water and would inhibit the growth of microorganisms in activated sludge. The objective of this study is to investigate biodegradability of tannin-containing wastewaters, so as to characterize the pollution properties of such wastewaters and provide a reference for their biological treatment in wastewater treatment plants. The research was typified by using the wastewater collected from vegetable tanning process in leather industry. A model was developed to describe the activated sludge process, and the biodegradation kinetics of vegetable tanning wastewater (VET wastewater) was studied. It was found that the biodegradability of tannin-containing wastewater varies heavily with the content of tannins in wastewater. The biodegradation of VET wastewater with tannin content around 4,900 mg/l occurred inefficiently due to the inhibition of tannins to the activated sludge process, and only 34.7% of biodegradation extent was reached in 14 days of incubation. The optimal biodegradability of VET wastewater was observed when its tannin content was diluted to 490 mg/l, where the COD and tannin removals reached 51.3% and 45.1% respectively in 6 days. Hence, it is suggested that a proper control of tannin content is necessary to achieve an effective biodegradation of tannin-containing wastewaters in wastewater treatment plants.

The adsorption of Pt(IV) and Pd(II) on bayberry tannin immobilized collagen fiber (BTICF) membrane was investigated. The optimal pH for the adsorption of Pt(IV) and Pd(II) ions was found to be 3.0 and 4.0, respectively. The time for attaining adsorption equilibrium of Pt(IV) and Pd(II) was 60 and 240 min. The adsorption kinetic data of the two metal ions are well fitted by the pseudo-second-order model. The adsorption capacities of Pt(IV) and Pd(II) on 0.100 g BTICF membrane were 41.7 and 27.5 mg/g at 313 K. The adsorption isotherms of the membrane to both the ions are described by the Langmiur model. The adsorption extent remarkably increases with the increase of temperature and the ratio of membrane material to solution volume. The membrane saturated by Pt(IV) is easily regenerated by 0.1 M thiuorea, but the full regeneration is difficult after adsorption of Pd(II). The continuous adsorption experiments of 58.3 mg/L Pt(IV) and 48.8 mg/L Pd(II) solutions were undertaken by using three layers of membrane (total area 191 cm 2 ), and it was found that no Pt(IV) and Pd(II) ions were detected until 700 and 1000 ml effluents were collected, respectively. Furthermore, competitive adsorption studies revealed that the membrane exhibits ability of selective adsorption to Pt(IV) and Pd(II) in the mixture solutions of metal ions. © 2005 Elsevier B.V. All rights reserved.

Gallotannins play contrasting roles in food quality. They exhibit strong antioxidative and antibacterial properties, and at the same time show certain antinutritional effects. To explore this possible effect of gallotannins, the interaction mechanism between gallotannins and typical food components was investigated. The molecular structure of gallotannins and their interactions with amino acids (glycine, alanine, proline and leucine) were first studied. It is proved that galloyl groups of gallotannins are hydrophobic sites and that these groups can interact with aliphatic side chains of amino acids through hydrophobic association. Further, the binding of gallotannins (1,2,6-tri- O -galloyl- d -glucose (TGG) and 1,2,3,4,6-penta- O -galloyl- d -glucose (PGG)) to typical proteins, phospholipids and sugars was examined quantitatively. It is indicated that gallotannins bound more to proteins (histone, bovine serum albumin, casein and gelatin) and phospholipids ( l -α-lecithin, l -α-cephalin and sphingomyelin) than to sugars, and that PGG had stronger binding affinity to proteins, phospholipids and sugars than did TGG. The gallotannin–protein and gallotannin–phospholipid interactions were the result of cooperative effects of hydrogen bonding and hydrophobic association, and hydrogen bonding was the predominant effect in the interactions between gallotannins and sugars.

The adsorption behavior of collagen fiber-immobilized bayberry tannin towards Bi(III) at acidic pH values was investigated. The adsorption capacity of the adsorbent towards Bi(III) was 0.348 mmol g−1 at 303 K, and increased with the rise in temperature. The adsorption isotherms of Bi(III) were in the shape of so-called type II isotherms and could be described by an empirical equation, ln qe = k + (1/n)Ce, which implies that chemical adsorption is predominant at lower concentrations of Bi(III) and that physical adsorption is involved at higher concentrations. The adsorption kinetics of Bi(III) on the immobilized bayberry tannin could be well described by the pseudo-second-order rate model, and the adsorption capacities calculated by the model were almost the same as those determined by actual measurements. The adsorbent could be regenerated by using 0.02 mol dm−3 ethylenediaminetetraacetic acid (EDTA) solution after adsorption of Bi(III). The adsorption selectivity of the immobilized bayberry tannin towards Bi(III) in a Cu(II)–Bi(III) binary solution in acidic medium was remarkable. Therefore, it is strongly suggested that the immobilized bayberry tannin could be applied to the removal of Bi(III) from crude Cu(II) samples under proper conditions. Copyright © 2006 Society of Chemical Industry

It was found that the collagen fiber immobilized bayberry tannin exhibited high adsorption capacity to Pt(II) and Pd(II). The adsorption isotherms of Pt(II) and Pd(II) could be well described by the Langmuir equation, and their adsorption capacities increased with the rise of temperature. The adsorption kinetics investigations indicated that the adsorption rate of Pt(II) and Pd(II) on the immobilized bayberry tannin could be well described by the pseudo-second-order rate model, and the adsorption capacities calculated by the pseudo-second-order rate model were close to those determined by actual measurement. The adsorption column could be easily regenerated by dilute HCl solution after adsorption of Pd(II), but it was somewhat difficult to regenerate the adsorption column after adsorption of Pt(II). The influence of pH value on the adsorption of Pd(II) and Pt(II) was not significant, and the immobilized bayberry tannin kept high adsorption capacity for these two precious metal ions even at acidic pH. In c...

Two fungal strains, effective in converting valonea (Quercus aegilops) tannins into ellagic acid (EA), were isolated from soil contaminated by valonea tannins, and were tentatively identified as Aspergillus niger and Candida utilis. Properties of EA accumulation by the two isolates from valonea tannins' fermentation were studied. Both the strains preferred sucrose to glucose as the additional carbon and energy source. The most suitable concentrations of valonea tannins in fermentation media for EA accumulation by A niger and C utilis were 5.0 and 9.0 g dm−3 with EA yields of 12.1 and 8.9% (w/w), respectively. The optimal temperature for the two strains was 28 °C, while the preferred pH values of the fermentation media were 4.5–5.0 for A niger and 4.8–5.2 for C utilis. The tannin tolerances of A niger and C utilis were adapted to 20 and 25 g dm−3 by gradually increasing the concentrations of valonea tannins in the culture media. The adapted strain of A niger was able to completely degrade 20 g dm−3 valonea tannins with an EA yield of 14.3% in 9 days. Meanwhile, the adapted strain of C utilis decreased the valonea tannins' level from 25 to 9.1 g dm−3 with an EA yield of 11.48%. The degradation ability of A niger came from tannase whose activity in the medium was 63 U cm−3 at the ninth day of fermentation, and that of C utilis was due to both tannase and polyphenol oxidase (PPO) whose activities were 32 U cm−3 and 29 U cm−3 at the ninth day. The coculture of both the adapted strains could completely degrade 25 g dm−3 valonea tannins in only 7 days with a remarkably increased EA yield (21%). The activities of tannase and PPO of the coculture at the seventh day were 66 U cm−3 and 47 U cm−3 respectively, which proved the synergistic effect of the two enzymes on valonea tannins' degradation and EA accumulation. Copyright © 2005 Society of Chemical Industry

A novel adsorbent, used for the selective removal of tannins from medicinal plant extracts, was prepared from bovine skin collagen fiber. Some typical active constituents of medicinal plants were selected as probe molecules to investigate the adsorption selectivity of the collagen fiber adsorbent to tannins. In batch adsorption experiments, the extent of adsorption of condensed tannins, including larch tannin, black wattle tannin and bayberry tannin, was 100%. The extent of adsorption of tannic acid and the hydrolyzable tannins was also 100%. In contrast, for the most active constituents of medicinal plants, their amounts adsorbed by collagen fiber adsorbent were limited. For procyanidin, the common active constituents in medicinal plant extracts, its extent of adsorption was also low, although it has a similar basic structure to condensed tannins. In comparison with traditionally used polyamide adsorbent, the collagen fiber adsorbent exhibited an obvious advantage in adsorption selectivity over tannins. Therefore, this study provides a novel and effective method for selective removal of tannins from medicinal plant extracts. Copyright © 2005 Society of Chemical Industry