Chloroperoxidase-catalyzed oxidation of N-methyl-4-chloroaniline
Chloroperoxidase catalyzed the H2O2 oxidative conversion of N-methyl-4-chloroaniline to 4-chloronitrosobenzene, 4-chloroaniline and a mixture of complex products.
New Trends in Fungal Biooxidation
Biooxidations using isolated biocatalysts for the oxidative conversion of organic compounds and materials are becoming more and more important in the industrial sector. Research in this direction is part of the rapidly developing field of White Biotechnology and is carried out not least against the background of sustainable development and the need to replace environmentally risky technologies by eco-friendly processes. Whereas whole cells are already widely used as oxidative biocatalysts, the application of isolated enzymes is still limited to a few examples. One reason for that is the cost-intensive production and laborious purification of enzymes which are mostly intracellular and sometimes membrane-bound proteins with low stability and complex co-factor requirements. The use of secreted oxidoreductases offers several advantages: they are easier to separate and purify, need only cheap co-substrates such as dioxygen or peroxides and are far more stable than intracellular enzymes. Filamentous fungi secrete a broad spectrum of oxidative biocatalysts which are involved, amongst others, in the degradation of recalcitrant biopolymers, the synthesis of melanins as well as the detoxification of plant ingredients, microbial metabolites and organopollutants. We focus here on novel secreted enzymes - peroxygenases and DyP-type peroxidases - with remarkable catalytic properties. Furthermore selected features of “classic” fungal oxidoreductases, such as laccase, tyrosinase and chloroperoxidase, are discussed against the background of innovative recent developments in the field of enzyme application.
Thermodynamics on the Carbochlorination of Titanium-bearing Ores
The equilibrium compositions of the multi-component, multi-phase and multi-reaction system of carbochlorination of titanium-bearing ores are calculated with HSC, a computational chemistry software. The thermodynamic equilibrium calculation of the reaction system shows that a complete conversion of titanium-bearing ores is feasible at a temperature near 200oC. At temperatures ranging from 800 to 1600oC, the products of the reaction system are all in gaseous phase. Thermodynamic analysis accords with the industrial practice. The simulated results provide reasonable scientific basis for improving suitable technological conditions of the carbochlorination reduction.