Chemical Engineering

An on‐line microfluidic system for determination of dissociation constants of enzyme/substrate weak interactions by nanoESI‐MS is introduced. The microchip was designed to permit the enzyme and the substrate to mix by molecular diffusion in a pressure‐driven laminar flow. Introduction of reagent solutions into the chip was an optimized combination of a micropump and an autosampler to enable automation of the measurements. The system performance was tested for monitoring of non‐covalent interactions of hen egg white lysozyme with N‐acetyl glucosamine oligomers. Dissociation constant (KD) of the hen egg white lysozyme‐N‐acetyl glucosamine oligomer complex was determined by non‐linear regression analysis, and the range of KD values (39±6×10−6 and 19.6±8×10−6 M for manual and automated infusions, respectively) confirms the previously reported values. Such miniaturization of a continuous‐flow enzyme assay system to a microfluidic format can maximize the capabilities of mass spectrometric...

Wastes are usually thought of as unwanted or unusable materials. Waste is any substance which is discarded after primary use, or considered worthless, defective, and of no use. The term is often subjective, as not every application has identical raw material requirements and sometimes even objectively inaccurate. A starting point towards managing waste is the division in basic categories, ranging from municipal and agricultural waste to radioactive and explosive waste. Through proper collection of municipal solid waste, very important metals and other valuable sources can be recovered and used in new products, thus achieving significantly lower production cost and environmental impact. Success stories in waste management are reported in countries around the world. These typically showcase optimal waste transformation to wealth. Furthermore, applied waste management methods are specified. These actions should be adapted by every organization handling waste. At a managerial level, the...

In the present study, a novel magnetic ethylene-based periodic mesoporous organosilica supported Pd-Schiff base complex (Fe3O4@PMO/SB-Pd) was prepared, characterized and applied as a recoverable nanocatalyst for green synthesis of Suzuki products. Chemical composition, magnetic and thermal behavior, morphology and particle size of Fe3O4@PMO/SB-Pd were investigated by using FT-IR, TGA, EDX, VSM, PXRD, TEM and Scanning electron microscopy (SEM) analyses. The Fe3O4@PMO/SB-Pd nanocomposite was applied as an efficient nanocatalyst in the Suzuki reaction under ultrasonic conditions giving corresponding products in high yield. Some advantages of this study are simple purification of products, the use of water solvent, easy catalyst separation, short reaction time and high catalyst efficiency and recoverability.

Membrane-based beverage dealcoholization is a successful process for producing low- and non-alcoholic beer and represents a fast-growing industry. Polyamide NF and RO membranes are commonly applied for this process. Polyelectrolyte multilayer (PEM) NF membranes are emerging as industrially relevant species and their unique properties (usually hollow fiber geometry, high and tunable selectivity, low fouling) underlines the importance of testing them in the food industry as well. To test PEM NF membranes for beer dealcoholization, at small pilot scale we dealcoholized filtered and unfiltered lager beer with the tightest available commercial polyelectrolyte multilayer NF membrane (NX Filtration dNF40), which has a MWCO=400Da which is quite high for these purposes. Dealcoholization is possible with a reasonable flux (10 LMH) at low pressures (5-8.6 bar) with a real extract loss of 16-18% and an alcohol passage of ~100%. Inorganic salt passage is high (which is typical for PEM NF membran...