Immobilization process improves the enzyme properties, like stability, activity, selectivity or specificity. In the study, a novel cysteine-functionalized MxOy (ZrO2, SiO2) material was used as a support for the immobilization of laccase from Trametes versicolor. The proposed matrix was prepared using a simple sol-gel method. The cysteine was introduced during the synthesis of a sample. Additionally, the obtained supports were modified with glutaraldehyde. The basic properties of the prepared cysteine functionalized ZrO2 and SiO2 were determined using spectroscopic, thermal, porous, electrostatic and elemental analysis. Furthermore, the obtained biocatalytic systems were used as catalysts in the oxidation of sulfonic acid. Catalytic and kinetic parameters were determined based on the proposed model reaction. Next, laccase immobilized on ZrO2- and SiO2-based materials were, for the first time, utilized in the decolorization of Alizarin Red S. In that process, the influence of duration,... [more]

Methane is the central component of natural gas, which is globally one of the most abundant feedstocks. Due to its strong C−H bond, methane activation is difficult, and its conversion into value-added chemicals and fuels has therefore been the pot of gold in the industry and academia for many years. Industrially, halogenation of methane is one of the most promising methane conversion routes, which is why this paper presents a comprehensive review of the literature on methane activation by halogenation. Homogeneous gas phase reactions and their pertinent reaction mechanisms and kinetics are presented as well as microkinetic models for methane reaction with chlorine, bromine, and iodine. The catalysts for non-oxidative and oxidative catalytic halogenation were reviewed for their activity and selectivity as well as their catalytic action. The highly reactive products of methane halogenation reactions are often converted to other chemicals in the same process, and these multi-step processe... [more]

The exhaustion of natural resources has increased petroleum prices and the environmental impact of oil has stimulated the search for an alternative source of energy such as biodiesel. Waste cooking oil is a potential replacement for vegetable oils in the production of biodiesel. Biodiesel is synthesized by direct transesterification of vegetable oils, which is controlled by several inputs or process variables, including the dosage of catalyst, process temperature, mixing speed, mixing time, humidity and impurities of waste cooking oil that was studied in this case. Yield, turbidity, density, viscosity and higher heating value are considered as outputs. This paper used multi-response surface methodology (MRS) with desirability functions to find the best combination of input variables used in the transesterification reactions to improve the production of biodiesel. In this case, several biodiesel optimization scenarios have been proposed. They are based on a desire to improve the biodies... [more]