Abstract:Azo, anthroquinone and triphenylmethane dyes are the major classes of synthetic colourants, which are difficult to degrade and have received considerable attention. Congo red, a diazo dye, is considered as a xenobiotic compound, and is recalcitrant to biodegradative processes. Nevertheless, during the last few years it has been demonstrated that several fungi, under certain environmental conditions, are able to transfer azo dyes to non toxic products using laccases. The aim of this work was to study the factor… Show more
“…(97%); however, the concentration of CR used in the present study (50 mg L −1 ) is higher than those reported for T. versicolor or Thelephora with 31 mg L −1 and 35 mg L −1 , respectively [57] (Table 1). In contrast, when the CR concentration was 50 mg L −1 , the removal observed for T. versicolor, 82%, for Aspergillus niger, 9%, for A. oryzae, 52%, for Penicillium chrysogenum, 10%, for Cladosporium rubrum, 10%, and Pleurotus ostreatus, 12% [58,59], were lower than that obtained in the present study. The removal percentages of CR by the dead mycelium of T. virens (94%) and T. viride (95%) are higher than those described for the mycelium of T. versicolor under three conditions: (a) autoclaved (90%), (b) acidic (49%), and (c) alkaline (42%) [58] (Table 1).…”
Section: Removal Of Cr and Mg By Fresh Biomass Of T Virens And T Viridecontrasting
The present study evaluated the removal efficiency of two dyes, Congo red (CR) and malachite green (MG), using either fresh or dry fungal biomass of two species of Trichoderma (T. virens and T. viride) and activated carbon. After 24 h, the CR removal efficiency obtained with fresh biomass was higher than that obtained with activated carbon. For the MG dye, the average removal with activated carbon (99%) was higher than those obtained with dry and fresh biomass of T. viride and T. virens. Experimental results for fresh and dry fungal biomass showed a good correlation with Langmuir isotherms. The adsorption rates of CR and MG by of T. virens and T. viride can be more appropriately described using the pseudo-second-order rate. We found an adsorption capacity of 81.82 mg g−1 for T. virens with MG dye. Results show that fresh or dry biomass of T. virens can represent a simple and cost-effective alternative for removing industrial dyes such as CR and MG.
“…(97%); however, the concentration of CR used in the present study (50 mg L −1 ) is higher than those reported for T. versicolor or Thelephora with 31 mg L −1 and 35 mg L −1 , respectively [57] (Table 1). In contrast, when the CR concentration was 50 mg L −1 , the removal observed for T. versicolor, 82%, for Aspergillus niger, 9%, for A. oryzae, 52%, for Penicillium chrysogenum, 10%, for Cladosporium rubrum, 10%, and Pleurotus ostreatus, 12% [58,59], were lower than that obtained in the present study. The removal percentages of CR by the dead mycelium of T. virens (94%) and T. viride (95%) are higher than those described for the mycelium of T. versicolor under three conditions: (a) autoclaved (90%), (b) acidic (49%), and (c) alkaline (42%) [58] (Table 1).…”
Section: Removal Of Cr and Mg By Fresh Biomass Of T Virens And T Viridecontrasting
The present study evaluated the removal efficiency of two dyes, Congo red (CR) and malachite green (MG), using either fresh or dry fungal biomass of two species of Trichoderma (T. virens and T. viride) and activated carbon. After 24 h, the CR removal efficiency obtained with fresh biomass was higher than that obtained with activated carbon. For the MG dye, the average removal with activated carbon (99%) was higher than those obtained with dry and fresh biomass of T. viride and T. virens. Experimental results for fresh and dry fungal biomass showed a good correlation with Langmuir isotherms. The adsorption rates of CR and MG by of T. virens and T. viride can be more appropriately described using the pseudo-second-order rate. We found an adsorption capacity of 81.82 mg g−1 for T. virens with MG dye. Results show that fresh or dry biomass of T. virens can represent a simple and cost-effective alternative for removing industrial dyes such as CR and MG.
“…As shown, the pH is a critical factor for MB biodegradation. It has been suggested that microbial cells are significantly affected by the pH of their immediate environment because they apparently have no mechanism for adjusting their internal pH [34]. The pH of dyes discharged in wastewater varies greatly as a result of their pH dependent nature.…”
Section: Effect Of Ph In the Removal Processmentioning
The conventional treatments used to remove dyes produced as a result of different industrial activities are not completely effective. At times, some toxic by-products are generated, affecting aquatic ecosystems. In this article, an efficient use of microorganisms is presented as a biodegradation technique that is a safe environmental alternative for the benefit of aquatic life. A strain of the yeast Galactomyces geotrichum KL20A isolated from Kumis (a Colombian natural fermented milk) was used for Methylene Blue (MB) bioremoval. Two parameters of the bioremediation process were studied at three different levels: initial dye concentration and growth temperature. The maximum time of MB exposure to the yeast was 48 h. Finally, a pseudo-first-order model was used to simulate the kinetics of the process. The removal percentages of MB, by action of G. geotrichum KL20A were greater than 70% under the best operating conditions and in addition, the kinetic simulation of the experimental results indicated that the constant rate of the process was 2.2 × 10-2 h−1 with a half time for biotransformation of 31.2 h. The cytotoxicity test based on the hemolytic reaction indicated that by-products obtained after the bioremoval process reached a much lower percentage of hemolysis (22%) compared to the hemolytic activity of the negative control (100%). All of these results suggest that the strain has the capacity to remove significant amounts of MB from wastewater effluents.
“…As opposed to adsorption, the degradation of azo dyes has been of significant interest as ideally, the dyes can be completely degraded by the microbial enzymes. Microorganisms capable of decolorizing and degrading dyes include filamentous fungi [87,88], yeasts [89,90], algae [91,92], and bacteria [93][94][95].…”
Azo dyes have become a staple in various industries, as colors play an important role in consumer choices. However, these dyes pose various health and environmental risks. Although different wastewater treatments are available, the search for more eco-friendly options persists. Bioremediation utilizing microorganisms has been of great interest to researchers and industries, as the transition toward greener solutions has become more in demand through the years. This review tackles the health and environmental repercussions of azo dyes and its metabolites, available biological approaches to eliminate such dyes from the environment with a focus on the use of different microorganisms, enzymes that are involved in the degradation of azo dyes, and recent trends that could be applied for the treatment of azo dyes.
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