Armillaria sp. F022, a basidiomycete fungus isolated from a recreational forest in Johor, Malaysia, was tested for its biodegradation ability of the azo dye Acid Red 27 (AR27). Varying carbon and nitrogen sources, agitation, and inoculum concentrations on AR27 dye degradation by Armillaria sp. F022 in liquid medium were investigated to find out their effects on dye degradation. Glucose and ammonium chloride were the best nutrients for the growth of Armillaria sp. F022. The addition of 15% inoculum concentration of Armillaria sp. F022 increased the AR27 dye degradation up to 97.17% within 72 h of incubation. Phytotoxicity tests were performed employing seed germination of Sorghum vulgare and Triticum aestivum by monitoring their elongation of the plumules and radicles to evaluate the toxicity of the degradation products. The metabolites formed during biodegradation were 1,4-naphthalenediol, 1,2-dihydroxynaphthalene, and coumarin, characterized by thin-layer chromatography and gas chromatography-mass spectrometry. Based on the findings of the AR27 biodegradation pathway it is proposed that Armillaria sp. F022 can be used to treat AR27 dye contaminated effluents to protect the ecosystem.

In this study, a glassy carbon electrode (GCE) was modified with multi-walled carbon nanotubes (MWCNTs), 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim]PF6), N,N0-bis(2-hydroxyacetophenone) ethylenediamine (BZE) and Nafion to form a MWCNT-BZE-[bmim]PF6-Nafion-GCE. The electrochemical behaviour of the modified electrode with respect to silver (Ag(I)) ion detection was studied by cyclic voltammetry (CV) and differential pulse anodic stripping voltammetry (DPASV). Furthermore, the experimental parameters including the pH value of Britton�Robinson Buffer (BRB), Nafion, MWCNTs, BZE and ([bmim]PF6) concentrations and the deposition potential and time were optimized. The detection limit of the modified electrode for the Ag(I) ion was found to be 70 ng L 1 (6.49 10 10 mol L 1). Repetitive measurements revealed good reproducibility with a relative standard deviation (RSD) value of 0.4%. The system performance of the modified electrode was highly satisfactory and the recoveries for river water samples were found to be 96�121%. This study proved that the MWCNT-BZE-[bmim]PF6-Nafion-GCE is a highly selective and sensitive modified electrode for the detection of the Ag(I) ion in river water samples with good recovery value.

Biogenic amines (BAs) are used as a quality indicator of food freshness that evaluates microbial action, which potentially affects human health and has become a major concern for consumers and health agencies around the world. Electrochemical biosensor technology, with its rapid tools and incredible potential, represents a major field that significantly impacts food quality control. This is a sensitive, green, and easily adaptable method that can detect BAs even at low concentrations. Numerous electrochemical biosensors with a combination of enzymes and nanomaterials are widely used in the fabrication of biosensors to increase their sensitivity. This article comprehensively reviews the basic concepts of biosensors, the mechanism and application of enzyme-based electrochemical biosensors, enzyme immobilization, and performance enhancing biosensors. In addition, the use of enzyme-based electrochemical biosensors as a modifier for the detection of BAs in spoiled food is also discussed.

In this study, fast growing ascomycete fungus Trichoderma atroviride F03 was explored to biodegrade bis-azo dye, Reactive Black 5 (RB5). The maximum RB5 biodegradation (91.1%) was achieved in the culture medium supplemented with an appropriate carbon source (glucose, 20 g l−1), and nitrogen source (yeast extract, 20 g l−1) at pH 5 and 27 °C. The laccase produced by T. atroviride F03 was involved in the RB5 biodegradation processes. The metabolites such as (I) 1,2,4-trimethylbenzene, (II) 2,4-ditertbutylphenol, and (III) benzoic acid-TMS) were identified as the biodegradation products of RB5 using gas chromatography-mass spectrometry (GC–MS). The presence of these metabolites suggested that RB5 biodegradation was initiated by the cleavage of azo bond forming naphthalene-1,2,8-triol and sulphuric acid mono-[2-(toluene-4-sulfonyl)-ethyl] ester. The sulphuric acid mono-[2-(toluene-4-sulfonyl)-ethyl] ester was further desulphonated to 1,2,4-trimethylbenzene. Then, the oxygenated ring of C1 and C2 naphthalene-1,2,8-triol was cleaved to 2-(2-carboxy-ethyl)-6-hydroxy-benzoic acid. The degradation of 2-(2-carboxy-ethyl)-6-hydroxy-benzoic acid could be proceeded with two pathways: (i) decarboxylation and methylation to form 2,4-ditertbutylphenol and (ii) decarboxylation mechanism that induced the formation of benzoic acid-TMS. Finally, this study proved that T. atroviride F03 might be a good candidate in treating textile effluent containing azo dye as this treatment does not generating aromatic amines. Keywords Azo dyeBiodegradation, Laccase, Metabolic pathway, Reactive black 5, Trichoderma atroviride F03

In this study, a newly isolated ascomycete fungus Trichoderma lixii F21 was explored to bioremediate the polar [Alizarin Red S (ARS)] and non-polar [Quinizarine Green SS (QGSS)] anthraquinone dyes. The bioremediation of ARS and QGSS by T. lixii F21 was found to be 77.78 and 98.31 %, respectively, via biosorption and enzymatic processes within 7 days of incubation. The maximum biosorption (ARS = 33.7 % and QGSS = 74.7 %) and enzymatic biodegradation (ARS = 44.1 % and QGSS = 23.6 %) were observed at pH 4 and 27 °C in the presence of glucose and yeast extract. The laccase and catechol 1,2-dioxygenase produced by T. lixii F21 were involved in the molecular conversions of ARS and QGSS to phenolic and carboxylic acid compounds, without the formation of toxic aromatic amines. This study suggests that T. lixii F21 may be a good candidate for the bioremediation of industrial effluents contaminated with anthraquinone dyes. Bioremediation Catechol 1,2-dioxygenase Laccase Trichoderma lixii