Fungal laccase-mediated humification of estrogens in aquatic ecosystems

Chen, Mingyu; Waigi, Michael Gatheru; Li, Shunyao; Sun, Kai; Si, Youbin

doi:10.1016/j.watres.2019.115040

Cited by 60 publications

(40 citation statements)

References 68 publications

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“…Laccase has a self as well as a cross-coupling mechanism for catalyzing single-electron oxidation, playing an important role in removing non-degradable organic pollutants [18]. It is now used as an effective and best alternative for chemical bleaching agents,which are used for paper bleaching in the paper industry [19].…”

Section: Introductionmentioning

confidence: 99%

Tree bark scrape fungus: A potential source of laccase for application in bioremediation of non-textile dyes

Sayyed

Bhamare²,

Sapna

et al. 2020

PLoS ONE

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Although laccase has been recognized as a wonder molecule and green enzyme, the use of low yielding fungal strains, poor production, purification, and low enzyme kinetics have hampered its large-scale application. Thus,this study aims to select high yielding fungal strains and optimize the production, purification, and kinetics of laccase of Aspergillus sp. HB_RZ4. The results obtained indicated that Aspergillus sp. HB_RZ4 produced a significantly large amount of laccase under meso-acidophilic shaking conditions in a medium containing glucose and yeast extract. A 25 μM CuSO 4 was observed to enhance the enzyme yield. The enzyme was best purified on a Sephadex G-100 column. The purified enzyme resembled laccase of A. flavus. The kinetics of the purified enzyme revealed high substrate specificity and good velocity of reaction,using ABTS as a substrate. The enzyme was observed to be stable over various pH values and temperatures. The peptide structure of the purified enzyme was found to resemble laccase of A. kawachii IFO 4308. The fungus was observed to decolorize various dyes independent of the requirement of a laccase mediator system. Aspergillus sp. HB_RZ4 was observed to be a potent natural producer of laccase, and it decolorized the dyes even in the absence of a laccase mediator system. Thus, it can be used for bioremediation of effluent that contains non-textile dyes.

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Section: Introductionmentioning

confidence: 99%

Tree bark scrape fungus: A potential source of laccase for application in bioremediation of non-textile dyes

Sayyed

Bhamare²,

Sapna

et al. 2020

PLoS ONE

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“…Humi cation refers to the process that the carbon of organic residues is converted into humus di cult to decompose by biochemical reactions (Chen et al, 2019;Lee et al, 2019). It is well-documented that natural enzyme can enhance humi cation and polymerization of organic compounds by reducing the reaction time and energy consumption (Lipczynska-Kochany, 2018; Yang et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

“…It follows that humi cation can serve as a vital natural decontamination and detoxi cation process of estrogens, and the core reaction is radical-centered oxidation and polymerization (Du et al, 2016;Feng et al, 2013). Thus, it is a novel strategy to utilize natural enzymecentered humi cation of estrogens and HAs for generating humi ed polymers (Chen et al, 2019;. Nevertheless, how to select a high-e cient oxidation-reduction enzyme for participating in the humi cation coupling reaction is particularly important.…”

Section: Introductionmentioning

confidence: 99%

“…(Baldrian, 2006;Madhavi and Lele, 2009). Simultaneously, four unstable radicals from substrates are produced, and then they encounter a series of non-enzymatic coupling reactions to form a variety of dimers, trimers, tetramers, oligomers, and polymers (Chen et al, 2019;Kudanga et al, 2011). It is well-documented that laccase plays a far-reaching role in humi cation and polymerization processes, especially for the substrates that contain phenolic -OH (Bilal and Iqbal, 2019;…”

Section: Introductionmentioning

confidence: 99%

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Effect of Two Humic Acids on Laccase-Driven 17β-Estradiol Conversion Kinetics and Polymerization Products at Varying pH Levels

Kim

Zhu

et al. 2021

Preprint

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Estrogens with tremendous ecological risks are proverbially found in water. Laccase can drive humification of estrogens to reduce their ecotoxicity and removability, but little investigation existed in exploring the effect of humic acids (HAs) on E2 conversion kinetics and polymerization products at different pH conditions. Here, Trametes versicolor laccase (Tvlac) was capable of efficiently converting a representative estrogen, 17β-estradiol (E2) with two different HAs, and the process followed a pseudo-first-order kinetics. The velocity constants were respectively 0.048, 0.022, and 0.020 min− 1 for HA-free, peat-derived HA, and commercial HA at pH 5.0. The changing pH not only impacted E2 coupling kinetics in Tvlac-evoked humification, but altered the aromaticity and humification degrees of HAs. A total of five intermediate species including estrone (E1), E2 dimer, trimer, and tetramer, as well as E1-E2 cross-linked products were tentatively detected, in which the dominating species were E2 self-oligomers resulting from radical-centered carbon-carbon/oxygen stepwise polymerization routes. Yields of dimeric, trimeric, and tetrameric species with increased molecular sizes were the highest at pH 5.0 in the given pH values, and they were readily handled by precipitation and filtration. Especially E2 was able to be covalently incorporated into humic constituents to generate new humified co-polymers, thereby accelerating E2 humification and detoxification. These findings demonstrate that pH exhibits a far-reaching influence on the conversion kinetics, humification degrees, and products distribution of E2 and HAs in Tvlac-reinforced polyreaction. Thus, there is need to reappraise the fate and transport of estrogens with HAs present in natural water at varying pH levels.

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“…The laccase has a self as well as a cross-coupling mechanism in catalyzing singleelectron oxidation playing an important role in removing non-degradable organic pollutants [18]. It is now used as effective and best alternative to chemical bleaching agents used for paper bleaching in the paper industry [19].…”

Section: Introductionmentioning

confidence: 99%

Tree bark scrape fungus: A potential source of laccase for application in bioremediation of non-textile dyes

Bhamare¹,

Sayyed

Marraiki

et al. 2020

Preprint

View full text Add to dashboard Cite

Although laccase has been recognized as a wonder molecule, and green enzyme, the use of low yielding fungal strains, poor production, purification, and low enzyme kinetics have hampered its larger-scale applications. Hence the present research was aimed to select high yielding fungal strains and to optimize the production, purification, and kinetics of laccase of Aspergillus sp. HB_RZ4. Aspergillus sp. HB_RZ4 produced a copious amount of laccase on under meso-acidophillic shaking conditions in a medium containing glucose and yeast extract. A 25 µM of CuSO 4 enhanced the enzyme yield. The enzyme was best purified on Sephadex G-100 column. Purified enzyme resembled with the laccase of A. flavus. Kinetics of purified enzyme revealed the high substrate specificity and good velocity of reaction with ABTS as substrate. The enzyme was stable over a wide range of pH and temperature. The peptide structure of the purified enzyme resembled with the laccase of A. kawachii IFO 4308. The fungus decolorized various dyes independent of the requirement of a laccase mediator system (LMS). Aspergillus sp. HB_RZ4 came out as a potent natural producer of laccase, it decolorized the dyes even in absence of LMS and thus can be used for bioremediation.

show abstract

Fungal laccase-mediated humification of estrogens in aquatic ecosystems

Cited by 60 publications

References 68 publications

Tree bark scrape fungus: A potential source of laccase for application in bioremediation of non-textile dyes

Tree bark scrape fungus: A potential source of laccase for application in bioremediation of non-textile dyes

Effect of Two Humic Acids on Laccase-Driven 17β-Estradiol Conversion Kinetics and Polymerization Products at Varying pH Levels

Tree bark scrape fungus: A potential source of laccase for application in bioremediation of non-textile dyes

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