engleski

OXIDATIVE ENZYMES IN REMOVAL OF DYES FROM TEXTILE WASTEWATERS

The textile industry is one of the biggest polluters of the environment, with significant consumption of water resources, energy and chemicals. Moreover, the processing of wastewaters from the textile industry is very complex, and the costs of these processes are very high. The main objective of this work was to select the most effective enzymes for wastewater treatment, as well as to detect dyes from different chemical groups which are mostly suitable for the enzymatic treatment and decolorization in the wastewaters of textile industry. 186 textile dyes were tested in reactions with six oxidative reductive enzymes (two laccases, lytic polysaccharide monooxygenase, cellobiose dehydrogenase, horseradish peroxidase and glucose oxidase), under different reaction conditions. The kinetics of pre-selected dyes and enzymes, as well as the toxicological properties of those dyes, were determined in batch reactions which were optimized by statistical method of the design of the experiment with regard to the concentrations of dyes, enzymes, temperature and pH values, and then scaled down to the microreactor levels. With the goal to perform scaling down to the level of micro-bioreactor, we have designed three prototypes of microreactors: i) microreactors produced in the workshop from two different materials and ii) printed by 3D printer. Results of reactions in microreactors were compared with the results achieved in the tubular and batch microreactor systems. All microreactors' prototypes were tested in the laboratory, using two enzymes and four different dyes. Studies have shown that the concentration of adsorbed oxygen measured in a microreactor system showed a linear increase with increasing flow rate. Decolorization of the Direct blue 78 dye in microreactors with and without aeration using laccase caused a 50% decrease in the decolorization speed, while in the tubular microreactor with aeration, the decolorization speed exponentially decreased by 80%. Those results should serve as a basis for the development of the wastewater treatment processes as well as for other enzymatic applications which are advantageous from an environmental and economical point of view.

enzyme; dye degradation; micro reactor; design of experiment

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