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Implication of ligninolytic enzymes produced by immobilized white-rot fungi in decolorization of synthetic dyes
Šušla, Martin ; Novotný, Čeněk (advisor) ; Gaper, Jan (referee) ; Masák, Jan (referee)
6 Abstract The aim of this Ph.D. thesis was to characterize ligninolytic activities of two white- rot fungi, Dichomitus squalens and Irpex lacteus, cultivated on various solid supports in their immobilized form and to identify the role of ligninolytic enzymes in the decolorization of synthetic dyes. Significant induction of laccase activity was observed in D. squalens pine wood cultures when compared to liquid cultures. The induction of laccase was probably due to the presence of phenols, extractable from wood with organic solvents. Two laccase isoforms, Lc1 and Lc2, were isolated from the culture liquid using FPLC. The enzymes revealed identical molecular masses of 68 kDa, however, they differed in isoelectric points and their dye decolorization capacity. The decolorization of the azo dye RO16 by Lc1 in the presence of redox mediator was followed by a regressive colorization of the sample when incubated for 72 h. Conversely, no backward trend was observed during RO16 decolorization using Lc2. In contrast to D. squalens, I. lacteus immobilized on pine wood cubes produced a low level of manganese peroxidases and no laccase induction was observed. Both fungi produced MnP as a dominant enzyme in solid state wheat straw cultures. D. squalens MnP obtained from the wheat straw cultures was able to decolorize...
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Ligninolytická kapacita vybraných hub bílé hniloby kultivovaných v imobilizované formě
Šušla, Martin ; Svobodová, Kateřina ; Tavčar, M. ; Pavko, A. ; Novotný, Čeněk
The work is focused on the ligninolytic capacity of two white-rot fungi, Irpex lacteus and Dichomitus squalens, cultivated in their immobilized form. We measured the production of ligninolytic enzymes (Mn-dependent peroxidase, lignin peroxidase, laccase) by the two fungi immobilized on polyurethane foam or pine wood in a fixed bed laboratory-scale bioreactor. The results were compared to the activity profiles of static liquid cultures of the fungi. Decolorization of an azo dye Reactive Orange 16 by the immobilized cultures of I. lacteus in three different bioreactor systems was also studied as well as the production of ligninolytic enzymes during the decolorization process. The highest dye decolorization efficiency (70% in 2 days) was observed in a small size trickle bed reactors
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Genotoxicita jako kriterium účinnosti biodegradace barviv v odpadních vodách
Doležílková, I. ; Pavlíčková, Z. ; Malachová, K. ; Lednická, D. ; Novotný, Čeněk ; Šušla, Martin
The aim of this study was to evaluate the mutagenicity of three mixtures of synthetic dyes used in textile industry. Detection of mutagenicity was carried out with three samples containing residues of textile dyes obtained from textile company Jitex Písek. Two different biodegradation process were used for elimination of genotoxicity, biodegradation using the bacterial activated sludge and the enzyme systém of the ligninolytic fungus Irpex lacteus. The genotoxicity of the samples was detected by the Ames test with and without metabolic activation in vitro, using S9 liver microsomal fraction and cofactor mixture. Salmonella typhimurium His- strain TA98 was employed for detection of frameshift mutations in the Ames test. During two different biodegradation processes (using bacterial activated sludge and the ligninolytic fungus Irpex lacteus), the change of mutagenicity of the degradation products of dyes was monitored
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