Validation and application of HPLC-ESI-MS/MS method for the quantification of RBBR decolorization, a model for highly toxic molecules, using several fungi strains

A Newly Validated HPLC-DAD Method for the Determination of Ricinoleic Acid (RA) in PLGA Nanocapsules

The assessment of ricinoleic acid (RA) incorporated into polymeric nanoparticles is a challenge that has not yet been explored. This bioactive compound, the main component of castor oil, has attracted attention in the pharmaceutical field for its valuable anti-inflammatory, antifungal, and antimicrobial properties. This work aims to develop a new and simple analytical method using high-performance liquid chromatography with diode-array detection (HPLC-DAD) for the identification and quantification of ricinoleic acid, with potential applicability in several other complex systems. The method was validated through analytical parameters, such as linearity, limit of detection and quantification, accuracy, precision, selectivity, and robustness. The physicochemical properties of the nanocapsules were characterized by dynamic light scattering (DLS) to determine their hydrodynamic mean diameter, polydispersity index (PDI), and zeta potential (ZP), via transmission electron microscopy (TEM) and quantifying the encapsulation efficiency. The proposed analytical method utilized a mobile phase consisting of a 65:35 ratio of acetonitrile to water, acidified with 1.5% phosphoric acid. It successfully depicted a symmetric peak of ricinoleic acid (retention time of 7.5 min) for both the standard and the RA present in the polymeric nanoparticles, enabling the quantification of the drug loaded into the nanocapsules. The nanocapsules containing ricinoleic acid (RA) exhibited an approximate size ranging from 309 nm to 441 nm, a PDI lower than 0.2, ζ values of approximately -30 mV, and high encapsulation efficiency (~99%). Overall, the developed HPLC-DAD procedure provides adequate confidence for the identification and quantification of ricinoleic acid in PLGA nanocapsules and other complex matrices.

Co-metabolic biodegradation of structurally discrepant dyestuffs by Klebsiella sp. KL-1: A molecular mechanism with regards to the differential responsiveness

In this study, an attempt was made to decipher the underlying differential response mechanism of Klebsiella sp. KL-1 induced by exposure to disparate categories of dyestuffs in xylose (Xyl) co-metabolic system. Here, representative reactive black 5 (RB5), remazol brilliant blue R (RBBR) and malachite green (MG) belonging to the azo, anthraquinone and triphenylmethane categories were employed as three model dyestuffs. Klebsiella sp. KL-1 enabled nearly 98%, 80% or 97% removal of contaminants in assays Xyl + RB5, Xyl + RBBR or Xyl + MG after 48 h, which was respectively 16%, 11% or 22% higher than those in the assays devoid of xylose. LC-QTOF-MS revealed an increased formation of smaller molecular weight intermediates in assay Xyl + RB5, whereas more metabolic pathways were deduced in assay Xyl + RBBR. Metaproteomics analysis displayed remarkable proteome alteration with regards to the structural difference effect of dyestuffs by Klebsiella sp. KL-1. Significant (p-value<0.05) activation of pivotal candidate NADH-quinone oxidoreductase occurred after 48 h of disparate dyestuff exposure but with varying abundance. Dominant FMN-dependent NADH-azoreductase, Cytochrome d terminal oxidase or Thiol peroxidase were likewise deemed to be responsible for the catalytic cleavage of RB5, RBBR or MG, respectively. Further, the differential response mechanism towards the structurally discrepant dyestuffs was put forward. Elevated reducing force associated with the corresponding functional proteins/enzymes was transferred to the exterior of the cell to differentially decompose the target contaminants. Overall, this study was dedicated to provide in-depth insights into the molecular response mechanism of co-metabolic degradation of refractory and structurally discrepant dyestuffs by an indigenous isolated Klebsiella strain.

Decolourisation of textile dye by laccase: Process evaluation and assessment of its degradation bioproducts

Biodegradation of environmentally hazardous synthetic dyes by enzymes has been achieved the highest interest in recent years. In this work, we optimized Remazol Brilliant Blue R (RBBR) dye biodegradation by Arthrographis kalrae derived laccase via the Box-Behnken design (BBD) approach of the surface response methodology (RSM). Optimization of dye decolourisation by one variable at a time (OVAT) approach resulted in optimal dye decolourisation at laccase dose (2 IU mL^-1), pH (7.0), temperature (35 °C), incubation time (240 min), and initial dye concentration (100 mg L^-1). The optimized process through BBD enhanced dye decolourisation (97.18%). Fourier Transform Infrared Spectroscopy and UV-Visible Spectrophotometry have proven biodegradation. In addition, in comparison to untreated samples, the laccase-treated dye sample showed relatively less phyto- and cytotoxic effect on Allium cepa L. Extra Precision Glide docking exhibited the binding affinity score of -5.355 kcal mol^-1, between laccase-RBBR complex.

Biodegradation and metabolic pathway of anthraquinone dyes by Trametes hirsuta D7 immobilized in light expanded clay aggregate and cytotoxicity assessment

Biodegradation and metabolic pathways of three anthraquinone dyes, Reactive Blue 4 (RB4), Remazol Brilliant Blue - R (RBBR), and Acid Blue 129 (AB129) by Trametes hirsuta D7 fungus immobilized in light expanded clay aggregate (LECA) were investigated. Morphological characteristics observed with scanning electron microscope (SEM) showed successful immobilization of the fungus in LECA. Based on UV absorbance measurement, immobilized T. hirsuta D7 effectively degraded 90%, 95%, and 96% of RB4, RBBR and AB129, respectively. Metabolites were identified with high-resolution mass spectrometry (HRMS) and degradation pathway of the dyes by T. hirsuta D7 was proposed. Toxicity assay on human dermal fibroblast (HDF) showed that anthraquinone dyes exhibits significant toxicity of 35%, 40%, and 34% reduction of cell viability by RB4, RBBR, and AB129, respectively. Fungal treatment resulted in an abatement of the toxicity and cell viability was increased up to 94%. The data clearly showed the effectiveness of immobilized T. hirsuta D7 in LECA on detoxification of anthraquinone dyes. This study provides potential and fundamental understanding of wastewater treatment using the newly isolated fungus T. hirsuta D7.

Marine associated microbial consortium applied to RBBR textile dye detoxification and decolorization: Combined approach and metatranscriptomic analysis

The combination of different microorganisms and their metabolisms makes the use of microbial consortia in bioremediation processes a useful approach. In this sense, this study aimed at structuring and selecting a marine microbial consortium for Remazol Brilliant Blue R (RBBR) detoxification and decolorization. Experimental design was applied to improve the culture conditions, and metatranscriptomic analysis to understand the enzymatic pathways. A promising consortium composed of Mucor racemosus CBMAI 847, Marasmiellus sp. CBMAI 1062, Bacillus subtilis CBMAI 707, and Dietzia maris CBMAI 705 was selected. This consortium showed 52% of detoxification and 86% of decolorization in the validation assays after seven days of incubation in the presence of 500 ppm of RBBR. Reduction in RBBR color and toxicity were achieved by biosorption and microbial metabolisms. Metatranscriptomic data indicate that the consortium was able to decolorize and breakdown the RBBR molecule using a coordinated action of oxidases, oxygenases, and hydrolases. Epoxide hydrolases and glyoxalases expression could be associated with the decrease in toxicity. The efficiency of this marine microbial consortium suggests their use in bioremediation processes of textile effluents.

Biotransformation and toxicity effect of monoanthraquinone dyes during Bjerkandera adusta CCBAS 930 cultures

The aim of this study was to evaluate of possibility of biotransformation and toxicity effect of monoanthraquinone dyes in cultures of Bjerkandera adusta CCBAS 930. Phenolic compounds, free radicals, phytotoxicity (Lepidium sativum L.), ecotoxicity (Vibrio fischeri) and cytotoxicity effect were evaluated to determine the toxicity of anthraquinone dyes before and after the treatment with B. adusta CCBAS 930. More than 80% of ABBB and AB129 was removed by biodegradation (decolorization) and biosorption, but biodegradation using oxidoreductases was the main dye removing mechanism. Secondary products toxic to plants and bacteria were formed in B. adusta strain CCBAS 930 cultures, despite efficient decolorization. ABBB and AB129 metabolites increased reactive oxygen species (ROS) production in human fibroblasts, but did not increase LDH release, did not affect the resazurine reduction assay and did not change caspase-9 or caspase-3 activity.

Decolorization of azo and anthraquinone dyes by crude laccase produced by Lentinus crinitus in solid state cultivation

White-rot basidiomycetes such as Lentinus crinitus produce laccases with potential use in dye biodegradation. However, high productivity and enzymes with specific properties are required in order to make viable laccase production. We aimed to produce laccase from Lentinus crinitus grown in sugarcane bagasse for dye decolorization. Solid state cultivation medium had sugarcane bagasse added with a nutrient solution of 10 g/L glucose, 1 g/L KH₂PO₄, 0.5 g/L MgSO₄, 0.001 g/L FeSO₄, 0.01 g/L ZnSO₄, and 0.01 g/L MnSO₄. The addition of different nitrogen sources (peptone, urea, or peptone plus urea) and different nitrogen concentrations (0, 0.4, 0.6, 0.8, 1.0, and 1.2 g/L) were evaluated. Enzymatic extract was used in the decolorization of azo dyes, reactive blue 220 (RB220) and reactive black 5 (RB5), and anthraquinone dye, Remazol brilliant blue R (RBBR). The greatest laccase activity (4800 U/g dry mass) occurred when the peptone and urea mixture was added to the solid state cultivation medium. When the nitrogen concentration was 1 g/L, the laccase activity increased to 6555 U/g dry mass. The laccase activity peak occurred on the 10th day, and the maximum decolorization within 24 h was observed with enzymatic extracts obtained on different cultivation days, i.e., 6th day for RB220, 10th day for RB5, and 9th day for RBBR. Manganese and lignin peroxidases were not produced when nitrogen was added to the cultivation medium. The crude enzymatic extract was more effective in the decolorization of azo dyes (RB220 and RB5), more than 90% of decolorization, than anthraquinone dye with 77% decolorization.

Characteristics of estrogenic/antiestrogenic activities during the anoxic/aerobic biotreatment process of simulated textile dyeing wastewater

HOA and HON were key fractions involved in increasing antiestrogenic activity and humic/fulvic acid in them could mask estrogenic activity.

A kinetic study of textile dyeing wastewater degradation by Penicillium chrysogenum

The potential of Penicillium chrysogenum to decolorize azo dyes and a real industrial textile wastewater was studied. P. chrysogenum was able to decolorize and degrade three azo dyes (200 mg L(-1)), either independently or in a mixture of them, using glucose as a carbon source. A kinetic model for degradation was developed and it allowed predicting the degradation kinetics of the mixture of the three azo dyes. In addition, P. chrysogenum was able to decolorize real industrial wastewater. The kinetic model proposed was also able to predict the decolorization of the real wastewater. The calibration of the proposed model makes it a useful tool for future wastewater facilities' design and for practical applications.

The marine-derived fungus Tinctoporellus sp. CBMAI 1061 degrades the dye Remazol Brilliant Blue R producing anthraquinones and unique tremulane sesquiterpenes

Conversion of RBBR dye to anthraquinones by the fungusTinctoporellussp., also producing novel tremulene terpenes.

Biodegradation of 1,2,3,4-tetrachlorodibenzo-p-dioxin in liquid broth by brown-rot fungi

Dioxins are a class of extremely hazardous molecules that might pose a threat to the environment. This work evaluated the microbial degradation of 1,2,3,4-tetrachlorodibenzo-p-dioxin (1,2,3,4-TCDD), in liquid broth using three brown-rot fungi and one white-rot fungi as control. A fast and reliable extraction method with recoveries of over 98% together with a validated GC-MS method was developed, and applied to quantify 1,2,3,4-TCDD in liquid broth, mycelia and reaction flask, with detection limits of 10 ppb. Among the four strains tested, brown-rot fungus Aspergillus aculeatus showed best results, removing up to 21% of dioxin after 30-day incubation. The results open both a path for biotechnological interest in bioremediation purposes and environmental behavior studies by using brown-rot fungus.