用工农业废料配制的两种堆肥培育观赏植物

由工农业废料配制的两种堆肥作为试验用的基质:C1——酿造啤酒等废料(酵母和麦芽)加修剪下的柠檬树枝;C2——橄榄研磨厂废水的固体级分加橄榄树叶。以每种堆肥与泥炭藓泥炭或商品基质(CS)按不同的比例混合,可配制成16种基质。尽管基质的物理和理化特性例如总孔隙度和电导率(EC)都是合适的,但由堆肥提供的养分(氮和钾)释放缓慢,对金盏花发育的影响尤为明显。另一方面,由于对盐分含量敏感,EC和氯化物浓度是影响蒲包草生长的主要因素。为供金盏花发育的适宜的基质可以通过含量高达75?与泥炭或高达50?与CS混合,以及高达50?与泥炭或CS混合使用。对蒲包花来说,基质中堆肥比例应较低,可用50?与泥炭或CS混合,也可以用25?与泥炭或CS混合使用。因此,只要基质至少含有25%的泥炭或CS,源于工农业废料的堆肥可作为培育观赏植物的泥炭和CS的替代品。     

固定化少根根霉发酵产脂肪酶及催化合成单甘酯

采用多种载体固定少根根霉细胞发酵产脂肪酶，发现珍珠岩和聚氨酯泡沫比较适合作固定化载体，发酵液酶活性比无载体直接发酵高6~8倍，而且产酶后固定化根霉细胞的废载体有较高酶活性，可直接作固定化细胞用于催化化学反应. 对根霉脂肪酶的性质进行了初步探讨. 提取的脂肪酶和固定化根霉细胞用于催化合成单甘酯，效果显著.     

Antibacterial activity and mechanism of piperazine polymer

Piperazine polymers poly(ethylenediaminetetraacetic dianhydride-co-piperazine) (PE) and MGF-Ct24E-modified poly(ethylenediaminetetraacetic dianhydride-co-piperazine) (PEM) showed good antibacterial activity. Considering their different applications, the effects of time, pH, and inoculation concentration of these antibacterials against Escherichia coli (E. coli) in unique environments were evaluated in this study. The results indicated that the MIC and MBC values of the polymers increased after the introduction of MGF-Ct24E into PE, but the two types of polymers still exhibited good antibacterial activity in a short time period under acidic conditions. In addition, we investigated the effect of the piperazine polymers on bacterial cell structure. It was clear that PE and PEM could destroy the bacterial cell wall, cell membrane and DNA, and their specific mechanism may be different. For PE, its carboxyl group could react with peptidoglycans on the E.coli cell wall to form holes on the bacterial surface, allowing PE to penetrate into the bacterial cell to damage DNA. For PEM, the alkaline MGF-Ct24E could adsorb E.coli and make it shrink, meanwhile, the PE component created small holes on the bacterial walls and membranes, and inserted into the bacteria to result in bactericidal effect. These findings reveal the potential usefulness of PE and PEM in biomedical applications.     

Preparation,Antibacterial and Physicochemical Behavior of Chitosan/Ofloxacin Complexes

A novel chitosan derivative with ofloxacin (OFX) has been successfully prepared. The IR and 1H-NMR results revealed that the chitosan/ofloxacin (CH-OFX) complex exhibited an electrostatic interaction. The crystalline and surface morphology were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The antimicrobial activity of the complexes against various micro-organisms viz. Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa and Staphylococcus aureus was tested. It was established that their antibacterial activity is up to four times greater than that of free quinolone drug and chitosan, probably due to the conjunction of favorable pharmacokinetics, excellent bacterial susceptibility and good stability towards metabolic degradation.     

Factors Influencing the Antibacterial Activity of Chitosan and Chitosan Modified by Functionalization

The biomedical and therapeutic importance of chitosan and chitosan derivatives is the subject of interdisciplinary research. In this analysis, we intended to consolidate some of the recent discoveries regarding the potential of chitosan and its derivatives to be used for biomedical and other purposes. Why chitosan? Because chitosan is a natural biopolymer that can be obtained from one of the most abundant polysaccharides in nature, which is chitin. Compared to other biopolymers, chitosan presents some advantages, such as accessibility, biocompatibility, biodegradability, and no toxicity, expressing significant antibacterial potential. In addition, through chemical processes, a high number of chitosan derivatives can be obtained with many possibilities for use. The presence of several types of functional groups in the structure of the polymer and the fact that it has cationic properties are determinant for the increased reactive properties of chitosan. We analyzed the intrinsic properties of chitosan in relation to its source: the molecular mass, the degree of deacetylation, and polymerization. We also studied the most important extrinsic factors responsible for different properties of chitosan, such as the type of bacteria on which chitosan is active. In addition, some chitosan derivatives obtained by functionalization and some complexes formed by chitosan with various metallic ions were studied. The present research can be extended in order to analyze many other factors than those mentioned. Further in this paper were discussed the most important factors that influence the antibacterial effect of chitosan and its derivatives. The aim was to demonstrate that the bactericidal effect of chitosan depends on a number of very complex factors, their knowledge being essential to explain the role of each of them for the bactericidal activity of this biopolymer.     

Synthesis and Characterization of NiO Nano‐Spheres by Templating on Chitosan as a Green Precursor

In this study, nickel oxide was prepared through the calcination of extrusion dripped chitosan/nickel nitrate beads. The morphology and structural properties of the products were studied using various characterization techniques. Uniformly distributed nickel oxide was formed as observed from the studies of surface morphology where the processing parameters play a huge role on the resulting morphology. TEM results have shown that nickel oxide with crystallite sizes of 10–30 nm was obtained. The Fourier‐transform infrared spectra studies show an intense peak at 525 cm^?1, which is attributed to the vibration of Ni–O bond. Furthermore, the XRD results show NiO diffraction peaks correspond to (111), (200), (220), (311), and (222) which indicates that a bunsenite structure with a face‐centered cubic phase was produced in this study. The usage of 500°C as the lower limit in this study is justified due to the complete removal of the templating material as seen in the thermalgravimetric analysis studies. Furthermore, it was obtained that the largest surface area of nickel oxide synthesized using this technique is 48.024 m²/g with pore sizes of 19.843 nm. The usage of chitosan as a green template for the synthesis of nanoparticles has shown promising results which allows a more economical and sustainable approach for the fabrication of nanomaterials.     

Adsorption of Silver Nanoparticles onto Different Surface Structures of Chitin/Chitosan and Correlations with Antimicrobial Activities

Size-controlled spherical silver nanoparticles (Ag NPs) can be simply prepared by autoclaving mixtures of glass powder containing silver with glucose. Moreover, chitins with varying degrees of deacetylation (DDAc < 30%) and chitosan powders and sheets (DDAc > 75%) with varying surface structure properties have been evaluated as Ag NP carriers. Chitin/chitosan-Ag NP composites in powder or sheet form were prepared by mixing Ag NP suspensions with each of the chitin/chitosan-based material at pH 7.3, leading to homogenous dispersion and stable adsorption of Ag NPs onto chitin carriers with nanoscale fiber-like surface structures, and chitosan carriers with nanoscale porous surface structures. Although these chitins exhibited mild antiviral, bactericidal, and antifungal activities, chitin powders with flat/smooth film-like surface structures had limited antimicrobial activities and Ag NP adsorption. The antimicrobial activities of chitin/chitosan-Ag NP composites increased with increasing amounts of adsorbed Ag NPs, suggesting that the surface structures of chitin/chitosan carriers strongly influence adsorption of Ag NPs and antimicrobial activities. These observations indicate that chitin/chitosan-Ag NPs with nanoscale surface structures have potential as antimicrobial biomaterials and anti-infectious wound dressings.     

新型两性壳聚糖衍生物的制取及应用研究

用氯乙酸和2,3-环氧丙基三甲基氯化铵对壳聚糖进行改性,采用不同反应条件制备了一系列不同取代度的O-羧甲基-N-羟丙基三甲基氯化铵壳聚糖。通过红外光谱对结构进行表征,IR谱图分析证实羧甲基以0位上为主,季铵盐阳离子基以N位上取代为主。研究了产物的取代度、吸湿保湿性、抗菌性、pH稳定性及与表面活性剂的配伍性,结果表明具有良好的吸湿保湿性。     

Antibacterial polyamide obtained by the incorporation of glass microparticles doped with ionic zinc and by zinc oxide nanoparticle: Evaluation with Salmonella typhimurium and Staphylococcus aureus

Food security is very important in all processes executed for the manufacture of meat in meatpacking industries. Meat security can be improved by the use of accessories produced with antimicrobial materials in the manufacture lines. In this work, the antibacterial property was incorporated in the plates of polyamide 6 by the addition of two antibacterial compounds and the antimicrobial characteristics were studied. The antibacterial materials used were glass microparticles doped with ionic zinc and zinc oxide nanoparticles. The antibacterial polyamide 6 was produced containing different percentages of antibacterial compound and its microbiological characterization was realized with the bacteria Salmonella typhimurium and Staphylococcus aureus. The distribution of the antimicrobial compound in polyamide 6 matrix was evaluated by scanning electron microscopy and energy dispersive spectroscopy. Atomic absorption spectrometry was applied to study the migration capacity of the antibacterial compound in the aqueous medium. The results demonstrated that the polyamide 6 containing glass microparticles doped with ionic zinc present better antibacterial action than the polyamide 6 containing zinc oxide nanoparticles. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45005.     

Biodegradation of Chloroxylenol by Cunninghamella elegans IM 1785/21GP and Trametes versicolor IM 373: Insight into Ecotoxicity and Metabolic Pathways

Chloroxylenol (PCMX) is applied as a preservative and disinfectant in personal care products, currently recommended for use to inactivate the SARS-CoV-2 virus. Its intensive application leads to the release of PCMX into the environment, which can have a harmful impact on aquatic and soil biotas. The aim of this study was to assess the mechanism of chloroxylenol biodegradation by the fungal strains Cunninghamella elegans IM 1785/21GP and Trametes versicolor IM 373, and investigate the ecotoxicity of emerging by-products. The residues of PCMX and formed metabolites were analysed using GC-MS. The elimination of PCMX in the cultures of tested microorganisms was above 70%. Five fungal by-products were detected for the first time. Identified intermediates were performed by dechlorination, hydroxylation, and oxidation reactions catalysed by cytochrome P450 enzymes and laccase. A real-time quantitative PCR analysis confirmed an increase in CYP450 genes expression in C. elegans cells. In the case of T. versicolor, spectrophotometric measurement of the oxidation of 2,20-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) showed a significant rise in laccase activity during PCMX elimination. Furthermore, with the use of bioindicators from different ecosystems (Daphtoxkit F and Phytotoxkit), it was revealed that the biodegradation process of PCMX had a detoxifying nature.     

Simulation and Modeling of Vegetable Market Wastes Pyrolysis Under Progressive Deactivation Condition

The pyrolysis behaviour of predried vegetable market waste has been investigated using TGA within the temperature range 523 to 923 K under inert atmosphere and a comparison has been made with other lignocellulosic materials in order to point out the difference between the pyrolysis of nearly homogeneous and perfectly mixed heterogeneous biomass. Kinetic parameters of the pyrolysis material have been evaluated from the simulation of the TG data. A reaction mechanism involving two parallel 1^st order reactions evolving gaseous products lumped as volatiles and solid products lumped as char has been proposed for prediction of rate constants as a function of normalized fractional change. Four kinetic models incorporating the effect of deactivation have been used for this purpose. In another attempt, using concentration independent model of solid deactivation, simulation has been carried out to predict concentration time history of the system components as well as quantitative change of rate constants with the propagation of time.     

银@石墨烯纳米复合材料的绿色制备及其抑菌性能

以聚乙二醇为还原剂通过水热反应,还原氧化石墨烯同时在石墨烯表面原位生长银纳米粒子,制备银@石墨烯纳米复合材料。采用紫外-可见吸收光谱、X射线衍射、红外吸收光谱、透射电子显微镜对所制备的银@石墨烯纳米复合材料进行了表征。结果表明：银以单质形态成功负载在石墨烯表面,银纳米粒子的平均粒径为30nm。以大肠杆菌为模型对纳米复合材料的抑菌性能进行测试,银@石墨烯纳米复合材料在100µg/mL时可以完全抑制大肠杆菌的生长,是一种效果显著的新型抑菌材料。     

植物油与水的两相溶剂体系中壳聚糖微粒的制备及抑菌性能研究

高浓度壳聚糖溶液制备得到粒径较小和均一的微粒,应用于食品的防腐与杀菌。采用壳聚糖在植物油与水的两相溶剂体系中与三聚磷酸钠(TPP)进行交联制备得到微粒,通过单因素实验确定其最适制备条件。然后通过其对大肠杆菌和金黄色葡萄球菌的杀菌实验研究其抑菌性能。当壳聚糖溶液的浓度为12 g·L-1时,可以制备得到平均粒径为(111.3±1.06)nm,PDI值为0.21±0.011。抑菌实验结果表明,当壳聚糖微粒浓度为125μg·mL-1时,壳聚糖微粒对大肠杆菌和金黄色葡萄球菌的杀菌率分别达到90.54%和91.34%。高浓度壳聚糖可以在植物油与水的两相溶剂体系中制备得到粒径较小和均一的微粒,并具有很好的杀菌活性。     

Preparation and Characterization of Hybrid Quaternized Chitosan/Acrylic Resin Emulsions and their Films

An acrylic resin emulsion containing a quaternary ammonium salt (hybrid q‐chitosan/acrylic resin emulsion) was prepared by emulsion polymerization using an acrylic monomer with and without DAAM. DAAM was used to incorporate a functional keto group into the acrylic resin emulsion. Furthermore, a hybrid chitosan/acrylic resin emulsion was prepared for comparison. The elution of q‐chitosan in water from the acrylic resin film with a keto group was less than that from the acrylic resin emulsion without a keto group. In addition, the mechanical properties of the hybrid q‐chitosan/acrylic resin film could be modified by q‐chitosan that was crosslinked between acrylic resin particles. Furthermore, hybrid q‐chitosan/acrylic resin films had adsorption ability for formaldehyde, and the antimicrobial properties of these films were superior to those of the hybrid chitosan/acrylic resin film.

     

Linear Copolymers Based on Choline Ionic Liquid Carrying Anti-Tuberculosis Drugs: Influence of Anion Type on Physicochemical Properties and Drug Release

In this study, drug nanocarriers were designed using linear copolymers with different contents of cholinium-based ionic liquid units, i.e., [2-(methacryloyloxy)ethyl]trimethylammonium chloride (TMAMA/Cl: 25, 50, and 75 mol%). The amphiphilicity of the copolymers was evaluated on the basis of their critical micelle concentration (CMC = 0.055–0.079 mg/mL), and their hydrophilicities were determined by water contact angles (WCA = 17°–46°). The chloride anions in the polymer chain were involved in ionic exchange reactions to introduce pharmaceutical anions, i.e., p-aminosalicylate (PAS⁻), clavulanate (CLV⁻), piperacillin (PIP⁻), and fusidate (FUS⁻), which are established antibacterial agents for treating lung and respiratory diseases. The exchange reaction efficiency decreased in the following order: CLV⁻ > PAS⁻ > PIP⁻ >> FUS⁻. The hydrophilicity of the ionic drug conjugates was slightly reduced, as indicated by the increased WCA values. The major fraction of particles with sizes ~20 nm was detected in systems with at least 50% TMAMA carrying PAS or PIP. The influence of the drug character and carrier structure was also observed in the kinetic profiles of the release processes driven by the exchange with phosphate anions (0.5–6.4 μg/mL). The obtained polymer-drug ionic conjugates (especially that with PAS) are promising carriers with potential medical applications.     

藤茶黄酮绿色制备纳米氧化锌及其抗氧化和抗菌性能

以藤茶黄酮为原料,采用溶液燃烧法绿色制备纳米氧化锌(Nano ZnO)粉末,并利用FTIR、XRD、SEM和EDS对所得样品进行结构分析和形貌观察;使用布兰德-威廉姆斯法、透明抑菌圈法和最小抑菌浓度法考察了绿色合成Nano ZnO的抗氧化性能和抑菌性能。结果表明,以藤茶黄酮为生物模板制备的Nano ZnO粒子为六方晶系纤锌矿结构,结晶度良好,晶粒平均尺寸约为32.7nm;该纳米材料具有良好的抗氧化活性,2.5g/L的Nano ZnO溶液对1,1-二苯基-2-三硝基苯肼自由基(DPPH·)的清除率为98.24%;藤茶黄酮绿色合成Nano ZnO对金色葡萄球菌的抑菌活性高于传统化学合成的Nano ZnO。绿色合成Nano ZnO的最小抑菌浓度为1.00 g/L,而化学合成Nano ZnO的最小抑菌浓度为1.50 g/L。     

纳米银@石墨烯复合材料的绿色制备及其抑菌性能

以聚乙二醇为还原剂通过水热反应,还原氧化石墨烯同时在石墨烯表面原位生长银纳米粒子,制备纳米银@石墨烯复合材料。采用紫外-可见吸收光谱、X射线衍射、红外吸收光谱、透射电子显微镜对所制备的纳米银@石墨烯复合材料进行了表征。结果表明,银以单质形态成功负载在石墨烯表面,银纳米粒子的平均粒径为30nm。以大肠杆菌为模型对纳米复合材料的抑菌性能进行测试,纳米银@石墨烯复合材料在100 mg/L时可以完全抑制大肠杆菌的生长,是一种效果显著的新型抑菌材料。     

MGF-Ct24E-modified piperazine polymer: A balance of antimicrobial activity and cytotoxicity

A piperazine oligomer (PE) has been successfully synthesized via green and facile conditions. To obtain equivalent or better antimicrobial activity and smaller cytotoxicity, a mechano-growth factor and its 24-amino acid peptide analog corresponding to the unique C-terminal E-domain (MGF-Ct24E) was introduced to the side chain of PE. Fourier transform infrared spectrometry (FTIR), elemental analysis, and amino acid analyzer (AAA) measurements showed that the MGF-Ct24E-modified piperazine polymer (PEM) was successfully prepared. The antibacterial activity and cytotoxicity of PEM were further investigated. Introduction of MGF-Ct24E resulted in equivalent or improved antibacterial properties and reduced cytotoxicity compared to PE. The resulting material may replenish the current arsenal of synthetic polymeric antibacterial systems reported. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47773.     

Culture Conditions and Investigation of Bioreactor Configurations for Lipase Production by Rhizopus oryzae

Lipolytic enzymes are the subject of great industrial and academic interest. For this reason, a detailed study of lipolytic enzyme production by the fungus Rhizopus oryzae is tackled, and several steps from plate to shake flasks and bioreactor cultures are investigated in order to propose an optimized strategy to perform the biological process. The suitability of several lipidic compounds and surfactants is assessed. Triton X‐100 (5 g/L) gives the highest activities with a maximum value of 6320 U/L which is 10‐fold the value attained in cultures without addition of lipidic compounds. As there are almost no studies on bench‐scale bioreactors, two bioreactor configurations, stirred tank and air‐lift, are investigated to determine the most suitable one to carry out the biological reaction. It is demonstrated that the lipolytic activity is strongly enhanced when a stirred‐tank bioreactor is used with a maximum value of 3521 U/L within two days which is clearly higher than the values produced by other recently reported species.     

Development of a Green Process for the Preparation of Antioxidant and Pigment-Enriched Extracts from Winery Solid Wastes Using Response Surface Methodology and Kinetics

Red grape pomace (RGP), an abundant wine industry solid waste, was used for the recovery of polyphenols and anthocyanin pigments, using ultrasound-assisted extraction and water/glycerol mixtures as the solvent. Glycerol concentration (C_gl) and liquid-to-solid ratio (R_L/S) were first optimized by implementing Box?Behnken experimental design and the process was further studied through kinetics. The optimal conditions were found to be C_gl = 90% (w/v) and R_L/S = 90 mL g^?1, and under these conditions the extraction of total polyphenols (TP) and total pigments (TPm) obeyed first-order kinetics. Maximum diffusivity (D_e) values were 4.22 × 10^?12 and 12.59 × 10^?12 m² s^?1, for TP and TPm, respectively, and the corresponding activation energies were (E_a) 13.94 and 8.22 kJ mol^?1.