A first report on competitive inhibition of laccase enzyme by lignin degradation intermediates

Pamidipati, Sirisha; Ahmed, Asma

doi:10.1007/s12223-019-00765-5

Cited by 7 publications

(6 citation statements)

References 29 publications

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“…The modeling of the enzyme kinetics assuming (global) Michaelis–Menten is a simplification and more advanced kinetic modeling will be necessary to fully understand the process (Cajnko et al, 2021 ). Lignin degradation products have been shown to act as a competitive inhibitor for laccase catalyzed ABTS oxidation, and therefore are likely to influence the lignin oxidation kinetics as well (Pamidipati & Ahmed, 2020 ).…”

Section: Discussionmentioning

confidence: 99%

Isothermal titration calorimetric assessment of lignin conversion by laccases

Islam

Zhang

Tonin

et al. 2021

Biotech & Bioengineering

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Lignin valorization may offer a sustainable approach to achieve a chemical industry that is not completely dependent on fossil resources for the production of aromatics.However, lignin is a recalcitrant, heterogeneous, and complex polymeric compound for which only very few catalysts can act in a predictable and reproducible manner.Laccase is one of those catalysts and has often been referred to as an ideal "green" catalyst, as it is able to oxidize various linkages within lignin to release aromatic products, with the use of molecular oxygen and formation of water as the only side product. The extent and rate of laccase-catalyzed lignin conversion were measured using the label-free analytical technique isothermal titration calorimetry (ITC). IITC provides the molar enthalpy of the reaction, which reflects the extent of conversion and the time-dependent power trace, which reflects the rate of the reaction. Calorimetric assessment of the lignin conversion brought about by various fungal and bacterial laccases in the absence of mediators showed marked differences in the extent and rate of conversion for the different enzymes. Kraft lignin conversion by Trametes versicolor laccase followed Michaelis-Menten kinetics and was characterized by the following thermodynamic and kinetic parameters ΔH ITC = −(2.06 ± 0.06)•10 3 kJ mol −1 , K M = 6.6 ± 1.2 μM and V max = 0.30 ± 0.02 U/mg at 25°C and pH 6.5. We envision calorimetric techniques as important tools for the development of enzymatic lignin valorization strategies.

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Section: Discussionmentioning

confidence: 99%

Isothermal titration calorimetric assessment of lignin conversion by laccases

Islam

Zhang

Tonin

et al. 2021

Biotech & Bioengineering

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“…Extracellular laccases have been reported in all three fungi tested [25,32,33], however some studies have indicated intracellular, membrane-associated laccases in T. viride [34]. This could be one of the factors contributing to the absence of laccase activity in the T. viride samples.…”

Section: Extent Of Bio-solubilisation and Laccase Activitymentioning

confidence: 98%

“…These two fungi were selected for their reported ability to degrade low-rank coal [12,14,17]. The third fungus, Neurospora discreta was previously isolated from a Subabul wood tree and was selected for its ability to produce ligninolytic enzymes and degrade lignin [24,25]. All fungi were sub-cultured on potato dextrose agar (PDA) plates and at 2-8 o C until further use.…”

Section: Fungal Solubilisation Of Coal Rejectsmentioning

confidence: 99%

“…Liquid supernatant obtained after centrifugation of samples from each ask was analysed for laccase activity based on oxidation kinetics of ABTS. Absorbance of the blue-green radical formed by the enzymatic oxidation of ABTS was measured at 420 nm and enzyme activity was calculated as the amount of enzyme forming 1 µM.min − 1 of product, using an extinction coe cient (ε 420 ) of 36000 L.mol.cm − 1 [25].…”

Section: Fungal Solubilisation Of Coal Rejectsmentioning

confidence: 99%

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Fungal Solubilisation and Subsequent Microbial Methanation of Coal Processing Wastes

Ahmed

Sharma

2021

Appl Biochem Biotechnol

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Large quantities of rejects from coal processing plants are currently disposed of as waste piles or in ponds and rivers, resulting in environmental concerns including pollution of rivers and ground and surface water contamination. This work investigates for the rst time, a two-stage microbial process for converting coal processing wastes to methane, involving (1) fungal solubilisation of coal rejects and (2) microbial methanation of the solubilised products. Phanerochaete chrysosporium, Trichoderma viride and Neurospora discreta were screened for their ability to solubilise coal rejects. N. discreta was found to be the most suitable candidate based on the extent of bio-solubilisation, laccase activity, and reversedphase high performance liquid chromatography (RP-HPLC) analysis. Bio-methanation of fungalsolubilised coal rejects was carried out in mesophilic anaerobic reactors with no additional carbon source, using inoculum from an anaerobic food digester. Coal rejects solubilised by N. discreta produced 3 to 6-fold higher methane compared to rejects solubilised by the other two fungi. No methane was produced from untreated coal rejects, demonstrating the importance of the fungal solubilisation stage. A total of 4.1 mmol methane was generated per gram of carbon in 15 days from N. discreta-solubilised coal rejects. This process offers a timely, environment-friendly, and sustainable solution for treatment of coal rejects and the generation of value-added products such as methane and volatile fatty acids.

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Section: Fungal Solubilisation Of Coal Rejectsmentioning

confidence: 99%

Fungal Solubilisation and Subsequent Microbial Methanation of Coal Processing Wastes

Ahmed

Sharma

2021

Preprint

Self Cite

View full text Add to dashboard Cite

Large quantities of rejects from coal processing plants are currently disposed of as waste piles or in ponds and rivers, resulting in environmental concerns including pollution of rivers and ground and surface water contamination. This work investigates for the first time, a two-stage microbial process for converting coal processing wastes to methane, involving (1) fungal solubilisation of coal rejects and (2) microbial methanation of the solubilised products. Phanerochaete chrysosporium, Trichoderma viride and Neurospora discreta were screened for their ability to solubilise coal rejects. N. discreta was found to be the most suitable candidate based on the extent of bio-solubilisation, laccase activity, and reversed-phase high performance liquid chromatography (RP-HPLC) analysis. Bio-methanation of fungal-solubilised coal rejects was carried out in mesophilic anaerobic reactors with no additional carbon source, using inoculum from an anaerobic food digester. Coal rejects solubilised by N. discreta produced 3 to 6-fold higher methane compared to rejects solubilised by the other two fungi. No methane was produced from untreated coal rejects, demonstrating the importance of the fungal solubilisation stage. A total of 4.1 mmol methane was generated per gram of carbon in 15 days from N. discreta-solubilised coal rejects. This process offers a timely, environment-friendly, and sustainable solution for treatment of coal rejects and the generation of value-added products such as methane and volatile fatty acids.

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A first report on competitive inhibition of laccase enzyme by lignin degradation intermediates

Cited by 7 publications

References 29 publications

Isothermal titration calorimetric assessment of lignin conversion by laccases

Isothermal titration calorimetric assessment of lignin conversion by laccases

Fungal Solubilisation and Subsequent Microbial Methanation of Coal Processing Wastes

Fungal Solubilisation and Subsequent Microbial Methanation of Coal Processing Wastes

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