Investigation of adsorption and biosorption features of bio-functionalized poly(GMA-Co-EGDMA) polymer beads in the treatment of nicotine from tobacco industry

The investigation of multifunctional materials for modern enzyme immobilization is an attractive subject in advanced adsorption and biosorption applications. In the present study, the feasibility of immobilization of Lipozyme TL 100L (LPZM) on 3-aminopropyltriethoxysilane (APTES) modified poly-(GMA-co-EGDMA) (PEGDMA) was investigated for adsorption and biosorption of nicotine from aqueous solution. Characterization tests confirmed successful immobilization of lipozyme which significantly altered thermal behavior, surface characteristics, and surface morphology of PEGDMA and PEGDMA/APTES. In addition, the immobilization yields were calculated as 85.0% and 72.0% onto PEGDMA/APTES using physical adsorption and covalent immobilization methods, respectively. The nicotine removal efficiencies were calculated to be 66.4%, 79.0%, 98.9%, and 85.7%, using raw PEGDMA, PEGDMA/APTES, PEGDMA/APTES@LPZM, and PEGDMA/APTES/GU@LPZM, respectively. For the raw PEGDMA, the Langmuir isotherm was best fitted to the adsorption data, while Langmuir-Freundich model described well the adsorption process on PEGDMA/APTES and PEGDMA/APTES@LPZM. The maximum adsorption capacities of Langmuir-Freundlich model increased from 8.118 to 17.32 mg/g after enzyme immobilization. The negative enthalpy value, ΔH° (- 10.37 kJ/mol), revealed that the nicotine adsorption on PEGDMA/APTES@LPZM was exothermic in nature, which was corroborated by the decrease observed in the number of adsorbed molecules with increasing temperature. In the kinetic experiments, the adsorption on PEGDMA and PEGDMA/APTES@LPZM reached equilibrium with the removal percentages as 66.4% and 98.9% at the end of 3 h, respectively. The nicotine adsorption performances in real water matrices were also investigated, and PEGDMA/APTES@LPZM showed satisfactory reusability with removal percentage decreased from 98.9% (1st cycle) to 83.0% (6th cycle).

Mechanism of Nonpolar Model Substances to Inhibit Primary Gushing Induced by Hydrophobin HFBI

In this work, the interactions of a well-studied hydrophobin with different types of nonpolar model substances and their impact on primary gushing is evaluated. The nature, length, and degree of saturation of nonpolar molecules are key parameters defining the gushing ability or inhibition. When mixed with hydrophobins, the nonpolar molecule-hydrophobin assembly acts as a less gushing or no gushing system. This effect can be explained in the framework of a competition effect between non-polar systems and CO2 to interact with the hydrophobic patch of the hydrophobin. Interactions of these molecules with hydrophobins are promoted as a result of the similar size of the nonpolar molecules with the hydrophobic patch of the protein, at the expense of the formation of nanobubbles with CO2. In order to prove the presence of interactions and to unravel the mechanisms behind them, a complete set of experimental techniques was used. Surface sensitive techniques clearly show the presence of the interactions, whose nature is not covalent nor hydrogen bonding according to infrared spectroscopy results. Interactions were also reflected by particle size analysis in which mixtures of particles displayed larger size than their pure component counterparts. Upon mixing with nonpolar molecules, the gushing ability of the protein is significantly disrupted.

Investigation of overfoaming activities and gushing mechanisms of individual beer ingredients as model substances in bottled carbonated water

BACKGROUND

Researchers in several disciplines are interested in understanding the spontaneous and eruptive overfoaming (gushing) of carbonated beverages, as it is an essential problem of both the brewing and beverage industries. In order to understand the mechanism(s) taking place in gushing beer, several beer ingredients have been investigated as model substances in a much simpler matrix of carbonated water. For this purpose, sinapic acid, vanillic acid, ferulic acid, cinnamic acid and palmitic acid have been chosen as model beer ingredients.

RESULTS

Gushing formation of the investigated beer ingredients depends on the degree of stabilized solvated molecular carbon dioxide in water. For this purpose, functional groups capable of forming hydrogen bonds with electronegative oxygen atoms of carbon dioxide are needed. However, the solubility of the substances plays an important role in the abundance of these functional groups in undissociated form to interact with molecular carbon dioxide.

CONCLUSION

The reported data provide valuable insights into the gushing problem and help to understand its formation pathways. Each gushing-positive substance has an individual mechanism related to its structural conformation and solubility level. Therefore possible gushing mechanisms have been proposed with respect to the structural changes in model substances to clarify the differences in observed overfoaming and gushing stability levels.

Development of an immobilization process for heavy metal containing galvanic solid wastes by use of sodium silicate and sodium tetraborate

Heavy metal containing sludges from wastewater treatment plants of electroplating industries are designated as hazardous waste since their improper disposal pose high risks to environment. In this research, heavy metal containing sludges of electroplating industries in an organized industrial zone of Istanbul/Turkey were used as real-sample model for development of an immobilization process with sodium tetraborate and sodium silicate as additives. The washed sludges have been precalcined in a rotary furnace at 900°C and fritted at three different temperatures of 850°C, 900°C and 950°C. The amounts of additives were adjusted to provide different acidic and basic oxide ratios in the precalcined sludge-additive mixtures. Leaching tests were conducted according to the toxicity characteristic leaching procedure Method 1311 of US-EPA. X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscope-energy dispersive spectrometer (SEM-EDS) and flame atomic absorption spectroscopy (FAAS) have been used to determine the physical and chemical changes in the products. Calculated oxide molar ratios in the precalcined sludge-additive mixtures and their leaching results have been used to optimize the stabilization process and to determine the intervals of the required oxide ratios which provide end-products resistant to leaching procedure of US-EPA. The developed immobilization-process provides lower energy consumption than sintering-vitrification processes of glass-ceramics.

Simultaneous investigation of sesquiterpenes, pyrrolizidine alkaloids and N-oxides in Butterbur (Petasites hybridus) with an offline 2D-combination of HPLC-UV and LC-MMI-ToF-MS

With the worldwide rapid increasing interest in the use of natural products as dietary supplements, medical remedies and functional foods, it has been accepted that omitting the plant constituents with potential adverse effects was a huge fault of the past. Several countries developed regulations to limit the consumption of such products in the markets. Among these natural products, butterbur (Petasites) has been used for years as herbal supplement for its anti-spasmodic and anti-inflammatory effects. However, its hepatotoxic alkaloid content limits the direct usage. In this study, investigation of sesquiterpenes and pyrrolizidine alkaloids (PAs) together with their N-oxide forms has been conducted with an offline 2D-combination using high-performance liquid chromatography with UV detection (HPLC-UV) and liquid chromatography - multi mode ionization - time-of-flight mass spectrometry (LC-MMI-ToF-MS) for plant screening. The content has been qualitatively investigated to provide information on the constituents of the plant rhizomes extracted using ethanol. Besides the reported hepatotoxic and medically bio-active plant constituents, a strategy has been suggested for estimating the retention order and retention times with respect to calculated logD (distribution coefficient) and hydrophobicity distributions on C18 reversed-phase column when all standard compounds are not available in laboratory. In this sense, the influence of calculated logD and hydrophobicity distributions on retention time has been clarified via available PA and PA-N-oxide standards. The ethanolic extract of Petasites hybridus has been used for examination of the strategy in a real-sample model. Additionally, the advantages of the developed HPLC-UV and LC-MMI-ToF-MS combination have been discussed with respect to the presented results.

The medical plant butterbur (Petasites): analytical and physiological (re)view

Butterbur (Petasites) is an ancient plant which has been used for medical and edible purposes with its spasmolytic agents. However, toxic alkaloid content of the plant limits its direct usage. The paper covers the pyrrolizidine alkaloids (PAs) and butterbur themes in detail in order to display the outline of alkaloid-free plant extract production for medical and edible purposes. The toxic PAs and medicinal constituents of the plant are described with emphasis on analytics, physiological effects and published patent data on alkaloid free extract production. The analytics is based on several commonly used analytical methods including liquid chromatography-mass spectrometry, gas chromatography-mass spectrometry and enzyme linked immunoassay analysis of PAs and N-oxides based on published literature data of butterbur. The analyses of major medicinal constituents of butterbur are given and the physiological effects of these compounds have been discussed to attract attention to the importance of alkaloid-free extract production. The concentration distributions of the medicinal constituents and toxic PAs in different parts of the plant and the outcomes of the published patent data provide comprehensive information for proper plant raw-material selection and production of alkaloid-free butterbur extracts. The review is intended to guide researchers interested in medical plant extracts by providing comprehensive data on the medical plant butterbur and its chemical constituents.