Versatile peroxidase degradation of humic substances: Use of isothermal titration calorimetry to assess kinetics, and applications to industrial wastes

Siddiqui, Khawar Sohail; Ertan, Haluk; Charlton, Timothy S.; Poljak, Anne; Khaled, Amina; Yang, Xu-Zhao; Marshall, Gavin; Cavicchioli, Ricardo

doi:10.1016/j.jbiotec.2014.03.002

Cited by 30 publications

(25 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Our results confirmed this, since the substrates treated with P. chrysosporium showed a decrease in these aromatic compounds. There are several reports where the phenolic content was reduced by the oxidization of phenyl groups and polymerization of free phenols after ligninolytic enzyme treatment, or even used as a carbon source for fungal growth [Chandel et al, 2013;Martins et al, 2011;Maza et al, 2014;Nicolaou et al, 2010;Parawira and Tekere, 2011;Siddiqui et al, 2014]. According to these results and those reported previously, the expression of recombinant fungal oxidoreductases could be directly associated with the improvement in the reduction of phenolic content.…”

Section: Discussionsupporting

confidence: 65%

“…Apparently, the combination and overproduction of MnP, LiP, VP, and LAC in the same cell played a key role in the decomposition of SB and WB. Although VP activity is a hybrid between MnP and LiP activities, recent findings have demonstrated that there is a synergy of VP activity on ligninolytic substrates when both LiP and MnP are active simultaneously [Siddiqui et al, 2014]. Possibly, the degradation of SB and WB lignin was initiated by LiP, VP, and accessory enzymes, since they have a high redox potential that allows cleaving of C-C and C-O-C linkages present in lignin [Ertan et al, 2012;Guerriero et al, 2016].…”

Section: Discussionmentioning

confidence: 99%

“…Lignin-derived phenolic contents include products of benzoic and hydroxycinnamic acids, mainly ferulic acid and diferulates of less than 2 kDa in size [Guerriero et al, 2016;Martins et al, 2011;Siddiqui et al, 2014]. It is well known that phenolic compounds can be reduced by treatment with ligninolytic enzymes changing their composition, structure, or molecular weight to less toxic forms [Asgher et al, 2008;Chandel et al, 2013;Siddiqui et al, 2014].…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Enhanced Delignification of Lignocellulosic Biomass by Recombinant Fungus Phanerochaete chrysosporium Overexpressing Laccases and Peroxidases

et al. 2018

View full text Add to dashboard Cite

Ligninolytic enzyme production and lignin degradation are typically the rate-limiting steps in the biofuel industry. To improve the efficiency of simultaneous bio-delignification and enzyme production, Phanerochaete chrysosporium was transformed by shock wave-induced acoustic cavitation to co-overexpress 3 peroxidases and 1 laccase and test it on the degradation of sugarcane bagasse and wheat bran. Lignin depolymerization was enhanced by up to 25% in the presence of recombinant fungi in comparison with the wild-type strain. Sugar release on lignocellulose was 2- to 6-fold higher by recombinant fungi as compared with the control. Wheat bran ostensibly stimulated the production of ligninolytic enzymes. The highest peroxidase activity from the recombinant strains was 2.6-fold higher, whereas the increase in laccase activity was 4-fold higher in comparison to the control. The improvement of lignin degradation was directly proportional to the highest peroxidase and laccase activity. Because various phenolic compounds released during lignocellulose degradation have proven to be toxic to cells and to inhibit enzyme activity, a significant reduction (over 40%) of the total phenolic content in the samples treated with recombinant strains was observed. To our knowledge, this is the first report that engineering P. chrysosporium enhances biodegradation of lignocellulosic biomass.

show abstract

Section: Discussionsupporting

confidence: 65%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Enhanced Delignification of Lignocellulosic Biomass by Recombinant Fungus Phanerochaete chrysosporium Overexpressing Laccases and Peroxidases

et al. 2018

View full text Add to dashboard Cite

show abstract

“…D=(K×λ)/(βcosθ) (1) where, D is the size of crystallite in nanometers, β is the peak width at half of the maximum intensity in radians, θ is the Bragg's angle for the peak in degrees, and λ is the wavelength of X-ray in nanometers.…”

Section: Characteristics Of Nanophotocatalystmentioning

confidence: 99%

“…Humic acid substances (HS) are very complex organic compounds derived from the decomposition of animal and plant tissues because of microbial activities (1,2). These substances constitute the main part of the natural organic matters (NOMs) in water resources (3).…”

Section: Introductionmentioning

confidence: 99%

Sonocatalytic Degradation of Humic Substances From Aquatic Environments Using MgO Nanoparticles

Soltani¹,

Safari²,

Rezaee³

et al. 2017

Avicenna J Environ Health Eng

View full text Add to dashboard Cite

Humic substances are considered as one of the major natural organic contaminants in water resources. Presence of such substances in the drinking water supply resources results in poor water quality and jeopardizes the consumer's health. In the present study, sonocatalytic decomposition of the humic substances by using MgO nanoparticles was investigated under the radiation of the ultrasonic waves. Accordingly, the X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques were used to determine characteristics of the nanoparticles. Furthermore, the effects of various parameters, including the amount of nanoparticles, initial pH, initial concentration of humic substances, contact time, as well as the power and frequency of ultrasonic waves on the efficiency of the sonocatalytic decomposition of humic substances were investigated. Results of the present study showed that the efficiency of sonocatalytic decomposition of humic substances was reduced by increasing the initial pH and initial concentration of the humic substances; while, the increased amount of the nanocatalyst resulted in the increased efficiency of decomposition. Furthermore, the obtained results indicated that the MgO sonocatalytic process could decompose the humic substances with the efficiency of 78.5% under optimal conditions (pH:7, initial concentration of humic substances: 20 mg/L, concentration of nanoparticles:1 g/L, power: 100%, frequency: 37 kHz and contact time:120 min). Based on the obtained results, the sonocatalytic method using MgO can remove humic substances and other similar organic matters from the aquatic environments with a high efficiency.

show abstract

The use of isothermal titration calorimetry for the assay of enzyme activity: Application in higher education practical classes

Siddiqui

Poljak

Ertan

et al. 2022

Biochem Molecular Bio Educ

Self Cite

View full text Add to dashboard Cite

Determination of enzyme activity is crucial for discovery, research, and development in life sciences. The activity of enzymes is routinely determined using spectrophotometric assays that measure rates of substrate consumption or product formation. Though colorimetric‐based detection systems are simple, rapid, and economical to perform, the majority of enzymes are unsuitable for this technique as their substrates/products do not absorb in the UV or visible range. This limitation can be addressed by the use of coupled‐enzyme assays or artificial chromogenic substrates; however these approaches have their own drawbacks. Here, we describe a method based on the use of an isothermal titration calorimeter (ITC) to measure the heat produced or absorbed during any enzyme‐catalyzed reaction. The concept of calorimetric enzyme assays was demonstrated for the determination of enzyme hexokinase activity, which cannot be monitored colorimetrically without first coupling it to another enzymatic reaction. The assay is suitable for incorporation into undergraduate laboratory classes, providing students with an appreciation for; the versatility and ease of use of ITC assays; ITC as a flexible generic method for exploring the functional characteristics of uncharacterized enzymes; an activity detection parameter suitable for enzymes that either have no straightforward colorimetric methods available or require the use of nonartificial chromogenic substrates.

show abstract

Versatile peroxidase degradation of humic substances: Use of isothermal titration calorimetry to assess kinetics, and applications to industrial wastes

Cited by 30 publications

References 41 publications

Enhanced Delignification of Lignocellulosic Biomass by Recombinant Fungus <b><i>Phanerochaete chrysosporium</i></b> Overexpressing Laccases and Peroxidases

Enhanced Delignification of Lignocellulosic Biomass by Recombinant Fungus <b><i>Phanerochaete chrysosporium</i></b> Overexpressing Laccases and Peroxidases

Sonocatalytic Degradation of Humic Substances From Aquatic Environments Using MgO Nanoparticles

The use of isothermal titration calorimetry for the assay of enzyme activity: Application in higher education practical classes

Contact Info

Product

Resources

About