Complete wastewater discoloration by a novel peroxidase source with promising bioxidative properties

The occurrence of micropollutants in aqueous matrices has become a global concern and a challenge for wastewater treatment plants. Monitoring their toxicity has shown that these compounds, even at low concentrations, pose risks to human and environmental health. Therefore, our study aimed to prospect immobilization strategies for non-commercial oxidoreductase enzymes and insert them in the context of pollutant remediation. The enzymatic extract was obtained by submerged fermentation of the fungus Trichoderma koningiopsis in an alternative substrate, consisting of fresh microalgal biomass from the phycoremediation process. The immobilization efficiency of peroxidase (POD) was evaluated by monitoring the residual activity (RA) and the discoloration potential (DP) of a synthetic dye solution. Concomitantly, the catalytic properties of free POD were explored, and the most promising storage strategy to maintain the enzymatic activity was studied. Guaiacol peroxidase from T. koningiopsis expressed specific activity of up to 7801.1 U mg− 1 in the free form, showing stability when subjected to up 80°C in a pH range between 4.0–8.0. Furthermore, the bioproduct immobilized on magnetic nanoparticles expressed up to 688% RA and 100% DP. An increase in the RA of the enzyme, both in free and immobilized form, was also observe after storage for up to 8 months. The synthesized magnetic nanozymes showed good reusability, maintaining 13546.4 U mg− 1 after ten cycles and removing 93% of color in a second batch. Toxicological evaluation with Allium cepa indicated that the enzymatic process of color removal with immobilized POD, despite maintaining unwanted cytotoxic effects, was essential to eliminate genotoxic effects. In this sense, the immobilization processes of T. koningiopsis peroxidase presented in our work are promising for the enzyme market and for the wastewater treatment sector.

Evidence for the Role of CYP51A and Xenobiotic Detoxification in Differential Sensitivity to Azole Fungicides in Boxwood Blight Pathogens

Boxwood blight, a fungal disease of ornamental plants (Buxus spp.), is caused by two sister species, Calonectria pseudonaviculata (Cps) and C. henricotiae (Che). Compared to Cps, Che is documented to display reduced sensitivity to fungicides, including the azole class of antifungals, which block synthesis of a key fungal membrane component, ergosterol. A previous study reported an ergosterol biosynthesis gene in Cps, CYP51A, to be a pseudogene, and RNA-Seq data confirm that a functional CYP51A is expressed only in Che. The lack of additional ergosterol biosynthesis genes showing significant differential expression suggests that the functional CYP51A in Che could contribute to reduced azole sensitivity when compared to Cps. RNA-Seq and bioinformatic analyses found that following azole treatment, 55 genes in Cps, belonging to diverse pathways, displayed a significant decrease in expression. Putative xenobiotic detoxification genes overexpressed in tetraconazole-treated Che encoded predicted monooxygenase and oxidoreductase enzymes. In summary, expression of a functional CYP51A gene and overexpression of predicted xenobiotic detoxification genes appear likely to contribute to differential fungicide sensitivity in these two sister taxa.

Structural and kinetic studies of human aldh7a1 and aldh9a1

The regulation and detoxification of endogenously and exogenously derived aldehydes is paramount to cellular survival due to the highly reactive nature of aldehydes as electrophiles. Human aldehyde dehydrogenases (ALDHs) are a superfamily of oxidoreductase enzymes that have critical roles in this regulation and detoxification. Misregulation of ALDH gene expression or mutations in the genes encoding for ALDHs lead to numerous disease pathologies. While extensive work has been conducted in understanding the metabolic roles and structures of these enzymes, there remains a need to further expand the structural and kinetic understanding of members of the human ALDH superfamily. This thesis aims to utilize the tools of structural biology and enzymology to expand the understanding of the ALDH superfamily.

Molecular Docking Studies of ROS Agent from Quinone Family to Reductase Enzymes:Implication in Finding Anticancer Drug Candidate

Understanding the metabolism of cytotoxic compounds of quinone family is importance in cancer therapy because they have been successfully explored for their anti-tumor activity. Quinone which form radical semiquinone (by reductase enzymes) to generate Reactive Oxygen Species (ROS) is associated to be anticancer drug candidate. However, molecular mechanism of those compounds to reductase enzymes has not yet clearly understood.This study aimed to understand molecular interaction of quinones to oxidoreductase enzymes such as cytochrome P450 reductase or ubiquinone reductase (NQO1), or apoptosis inducing factor (AIF) which is recently reported as NADH:quinone reductase. In silico approach was applied to find the best affinity of each compound to enzymes. Optimize ligands were employed using Marvin sketch program. Molecular interaction using autodockvina software was built to measure important residues for quinone reduction. Docking analysis showed that generally quinones prefer bound to cytochrome P450 reductase rather than NQO1 or AIF. The number of ring seems affect to the affinity, but not for its functional groups. Residues analysis confirmed that reduction of quinone is NAD(P)H: dependent. The result revealedthat all ligands have high possibility to compete with their redox coupleswhich is needed in its capacity as an anti-cancer drug.

Tyrosinase and laccase-producing Bacillus aryabhattai TFG5 and its role in the polymerization of phenols

Background Tyrosinases and laccases are oxidoreductase enzymes that are used widely in the food, feed, textile, and biofuel industries. The rapidly growing industrial demand for bacterial oxido-reductases has encouraged research on this enzyme worldwide. These enzymes also play a key role in the formation of humic substances (HS) that are involved in controlling the biogeochemical carbon cycle, providing nutrients and bio-stimulants for plant growth, and interacting with inorganic and organic pollutants besides increasing carbon sequestration and mitigating greenhouse gas emission in the environment. The present study aimed to screen and characterize extracellular tyrosinase and laccase-producing soil bacteria that could be utilized in the polymerization of phenols. Results Twenty isolates from different soil samples collected from forest ecosystems were characterized through ARDRA using restriction digestion with AluI, HpaII, and HaeIII restriction enzymes. The results of Hierarchical Cluster Analysis (HCA) revealed a 60 % similarity coefficient among 13 out of 20 isolates, of which, the isolate TFG5 exhibited only 10 % similarity when compared to all the other isolates. The isolate TFG5 exhibited both tyrosinase (1.34 U.mL− 1) and laccase (2.01 U.mL− 1) activity and was identified as Bacillus aryabhattai. The increased polymerization activity was observed when B. aryabhattai TFG5 was treated with phenols. The monomers such as catechol, p-Hydroxy benzoic acid, ferulic acid, and salicylic acid were polymerized efficiently, as evidenced by their FT-IR spectra depicting increased functional groups compared to the standard mushroom tyrosinase. Conclusions The polymerization ability of B. aryabhattai TFG5 could be applied to phenol-rich wastewater treatment for efficient precipitation of phenols. Furthermore, tyrosinases can be used for enhancing the synthesis of HS in soil.

A Brief History of Colour, the Environmental Impact of Synthetic Dyes and Removal by Using Laccases

The history of colour is fascinating from a social and artistic viewpoint because it shows the way; use; and importance acquired. The use of colours date back to the Stone Age (the first news of cave paintings); colour has contributed to the social and symbolic development of civilizations. Colour has been associated with hierarchy; power and leadership in some of them. The advent of synthetic dyes has revolutionized the colour industry; and due to their low cost; their use has spread to different industrial sectors. Although the percentage of coloured wastewater discharged by the textile; food; pharmaceutical; cosmetic; and paper industries; among other productive areas; are unknown; the toxic effect and ecological implications of this discharged into water bodies are harmful. This review briefly shows the social and artistic history surrounding the discovery and use of natural and synthetic dyes. We summarise the environmental impact caused by the discharge of untreated or poorly treated coloured wastewater to water bodies; which has led to physical; chemical and biological treatments to reduce the colour units so as important physicochemical parameters. We also focus on laccase utility (EC 1.10.3.2), for discolouration enzymatic treatment of coloured wastewater, before its discharge into water bodies. Laccases (p-diphenol: oxidoreductase dioxide) are multicopper oxidoreductase enzymes widely distributed in plants, insects, bacteria, and fungi. Fungal laccases have employed for wastewater colour removal due to their high redox potential. This review includes an analysis of the stability of laccases, the factors that influence production at high scales to achieve discolouration of high volumes of contaminated wastewater, the biotechnological impact of laccases, and the degradation routes that some dyes may follow when using the laccase for colour removal

Cascade Biocatalysis Designed for the Allylic Oxidation of α-Pinene

A biocatalytic cascade system using a cocktail of oxidoreductase enzymes (2-1B peroxidase and M120 laccase) was designed for the allylic oxidation of (+)-α-pinene into value-added products (e.g., verbenol and verbenone). The oxidative transformation involved a two-step process as follows: (+)-α-pinene was (i) oxidized on the allylic position with H2O2 mainly assisted by 2-1B peroxidase leading to verbenol as the principal reaction product, and (ii) directed to verbenone in the presence of M120 laccase responsible for further oxidation of verbenol to verbenone. The reaction environment was ensured by the acetate buffer (0.1 M, pH = 5). Optimum values for the experimental parameters (e.g., concentration of 2-1B peroxidase, M120 laccase, and H2O2) were set up. The biocatalytic cascade process was monitored for 24 h in order to evaluate the process pathway. Maximum performance under optimum conditions was reached after 5 h incubation time (e.g., 80% (+)-α-pinene conversion and 70% yield in verbenol). Therefore, the developed biocatalytic cascade system offered promising perspectives for (+)-α-pinene valorization.

Solid-state fermentation with orange waste: optimization of Laccase production from Pleurotus pulmonarius CCB-20 and decolorization of synthetic dyes

Laccases are oxidoreductase enzymes that have the ability to oxidize phenolic substrates. Its biotechnological potential has been greatly explored in many areas as biotechnology industry, bioremediation of dyes, food industry and environmental microbiology. The aim of this study was maximize the laccase production by Pleurotus pulmonarius (Fr.) Quélet in solid-state fermentation (SSF) using orange waste as substrate. After optimization the capability of the crude laccase to decolorize dyes was analyzed. The fermentation medium in the solid-state was optimized by applying a factorial design. After statistics optimization, laccase activity increased two times. The laccase activity appears to be correlated with the ability of crude extract to decolorize some industrial dyes. The optimized laccase was characterized with respect to optimum pH, influence of temperature and salts. Our results demonstrate that P. pulmonarius was an efficient producer of an important industrial enzyme, laccase, in a cheap solid-state system using orange waste as substrate.