Comparative degradation of azo dye cocktail by free and chitosan-immobilized fungal consortia with concomitant expression of lignin-modifying enzymes

Abstract

For solubilizing and degrading the recalcitrant structures of persistent azo dyes—Congo Red (CR) and Amido Black (AB), immobilized microbial consortium comprising at least one biosurfactant producer is effective. Hence, in the present study three potent fungi—Lasiodiplodia sp., P. ostreatus, and H. lixii (biosurfactant producer) were evaluated for the degradation of a cocktail of CR and AB for real-time studies. Individually, for 25 mg/L CR, P. ostreatus exhibited the highest degradation (100%), followed by H. lixii (91.3%) and Lasiodiplodia sp. (89.5%); while for AB, H. lixii showed maximum degradation (99.8%), followed by P. ostreatus within 15 days. In both cases, degradation accompanied concomitant expression of ligninolytic modifying enzymes (LMEs). Based on antagonism, consortium of H. lixii and P. ostreatus was formulated for the degradation of dye cocktail (CR & AB). Free fungal biomass degraded 70.23% CR and 64.56% AB in 15 days, while chitosan-fungal consortia degraded 90.00% CR and 95.67% AB in only 6 days. Moreover, the lowering of surface tension from 54.14 to 44.2 mN/m indicated retained biosurfactant-producing ability of immobilized H. lixii. UV–Visible spectral and FTIR analysis confirmed effective degradation with absence/shift of absorption peaks characteristic of both dyes. GC–MS analysis revealed the identification of intermediate metabolites. Overall, enhanced degradation can be attributed to the synergistic effects of LMEs expression, biosurfactant production, increased surface area, and protection against dye toxicity conferred by cell immobilization. These findings highlight the potential of chitosan-immobilized fungal consortium as an efficient and sustainable approach for treating complex azo dye effluents.

Keywords

Azo dyes / Lignin- modifying enzymes / Fungal consortium / Chitosan beads

References

[1] Asses N, Ayed L, Hkiri N, Hamdi M. Congo red decolorization and detoxification by Aspergillus niger: removal mechanisms and dye degradation pathway. Biomed Res Int, 2018, 1: 3049686.

[2] Balachandran B, Sabumon PC. Comprehensive review on biodegradation of azo dye mixtures, metabolite profiling with health implications and removal strategies. J Hazard Mater Adv, 2025.

[3] Borham A, Okla MK, El-Tayeb MA, Gharib A, Hafiz H, Liu L, Zhao C, Xie R, He N, Zhang S, Wang J. Decolorization of textile azo dye via solid-state fermented wheat bran by Lasiodiplodia sp. YZH1. J Fungi, 2023, 9111069

[4] Bustos-Terrones YA. A review of the strategic use of sodium alginate polymer in the immobilization of microorganisms for water recycling. Polymers, 2024, 166788

[5] Carrascal-Hernández DC, Orozco-Beltrán EJ, Insuasty D, Márquez E, Grande-Tovar CD. Systematic evaluation of biodegradation of azo dyes by microorganisms: efficient species, physicochemical factors, and enzymatic systems. Int J Mol Sci, 2025, 26167973

[6] Chaturvedi M, Joy S, Gupta RD, Pandey S, Sharma S. Endocrine disrupting chemicals (EDCs): chemical fate, distribution, analytical methods and promising remediation strategies-a critical review. Environ Technol Rev, 2023, 121286315.

[7] Chaturvedi M, Kaur N, Rahman PK, Sharma S. Solubilization and enhanced degradation of benzene phenolic derivatives—Bisphenol A/Triclosan using a biosurfactant producing white rot fungus Hypocrea lixii S5 with plant growth promoting traits. Front Microbiol, 2024, 15. 1433745

[8] Chaturvedi M, Kaur N, Jeyaseelan C, Sillanpää M, Al Farraj S, Sharma S. Composites of sodium alginate based-functional materials towards sustainable adsorption of benzene phenol derivatives-bisphenol A/triclosan. Environ Res, 2024, 255. 119192

[9] da Cruz Brambilla CM, Garcia AL, da Silva FR, Taffarel SR, Grivicich I, Picada JN, Scotti A, Dalberto D, Mišík M, Knasmüller S, da Silva J. Amido Black 10B a widely used azo dye causes DNA damage in pro-and eukaryotic indicator cells. Chemosphere, 2019, 217: 430-436.

[10] Deng W, Ge M, Wang Z, Weng C, Yang Y. Efficient degradation and detoxification of structurally different dyes and mixed dyes by LAC-4 laccase purified from white-rot fungi Ganoderma lucidum. Ecotoxicol Environ Saf, 2024, 279. 116450

[11] Dutta S, Adhikary S, Bhattacharya S, Roy D, Chatterjee S, Chakraborty A, Banerjee D, Ganguly A, Nanda S, Rajak P. Contamination of textile dyes in aquatic environment: adverse impacts on aquatic ecosystem and human health, and its management using bioremediation. J Environ Manage, 2024, 353. 120103

[12] Eras-Muñoz E, Farré A, Sánchez A, Font X, Gea T. Microbial biosurfactants: a review of recent environmental applications. Bioengineered, 2022, 1351236512391.

[13] Hashemi-Mashouf MM, Nematollahi D, Alaei M. Comparative degradation of amido black 10B and Bismarck brown by electro-Fenton process. Comprehensive electrochemical study and degradation pathway of amido black 10B. Results Eng, 2025.

[14] https://www.marketsandmarkets.com/Market-Reports/synthetic-dyes-market-184747754.html

[15] Khan A, Ju P, Han Z, Ni C. A comprehensive review on adsorptive removal of azo dyes using functional materials. Aqua Water Infrastruct Ecosyst Soc, 2024, 732266285.

[16] Lade H, Kadam A, Paul D, Govindwar S. Exploring the potential of fungal-bacterial consortium for low-cost biodegradation and detoxification of textile effluent. Arch Environ Prot, 2016, 4241221.

[17] Lellis B, Fávaro-Polonio CZ, Pamphile JA, Polonio JC. Effects of textile dyes on health and the environment and bioremediation potential of living organisms. Biotechnol Res Innov, 2019, 32275290.

[18] Liu C, You Y, Zhao R, Sun D, Zhang P, Jiang J, Zhu A, Liu W. Biosurfactant production from Pseudomonas taiwanensis L1011 and its application in accelerating the chemical and biological decolorization of azo dyes. Ecotoxicol Environ Saf, 2017, 145: 8-15.

[19] Liu J, Chen J, Zuo K, Li H, Peng F, Ran Q, Wang R, Jiang Z, Song H. Chemically induced oxidative stress improved bacterial laccase-mediated degradation and detoxification of the synthetic dyes. Ecotoxicol Environ Saf, 2021, 226. 112823

[20] Mamand DM, Ahmed BY, Aziz DM, Hama PO, Mohammed PA, Abdalkarim KA, Muhammad DS, Hussein AM, Hussen SA, Aziz SB, Hassan J. Advanced spectroscopic approach for exploring the structural, optical, and electronic properties in dye-functionalized chitosan biopolymers. Spectrochim Acta A Mol Biomol Spectrosc, 2025, 329. 125485

[21] Modi A, Baranda P, Thakor R, Thacker D, Trivedi J, Bariya H. Fungal consortium mediated efficient biodegradation of hazardous reactive dyes from textile effluent: an environmentally acceptable strategy. J Hazard Mater Adv, 2025, 18. 100705

[22] Mohan D, Shukla SP. Hazardous consequences of textile mill effluents on soil and their remediation approaches. Clean Eng Technol, 2022, 7. 100434

[23] Pandey A, Singh P, Iyengar L. Bacterial decolorization and degradation of azo dyes. Int Biodeterior Biodegrad, 2007, 5927384.

[24] Przystaś W, Zabłocka-Godlewska E, Grabińska-Sota E. Efficiency of decolorization of different dyes using fungal biomass immobilized on different solid supports. Braz J Microbiol, 2018, 492285295.

[25] Raheema R, Hadi S, Dirwal A. Microbial bioremediation for sustainable development. Microbe, 2026.

[26] Routoula E, Patwardhan SV. Degradation of anthraquinone dyes from effluents: a review focusing on enzymatic dye degradation with industrial potential. Environ Sci Technol, 2020, 542647664.

[27] Sahoo PP, Pallavi P, Sahoo AA, Sen SK, Raut S. Comparative evaluation of suspended and chitosan-encapsulated WRF consortium for decolorization of anthraquinone dye mixture. Environ Prog Sustain Energy, 2025, 445e70032

[28] Saputra HA. Chitosan and its biomedical applications: a review. Next Mater, 2025, 9. 101270

[29] Saratale RG, Saratale GD, Chang JS, Govindwar SP. Decolorization and degradation of reactive azo dyes by fixed bed bioreactors containing immobilized cells of Proteus vulgaris NCIM-2027. Biotechnol Bioprocess Eng, 2011, 164830842.

[30] Siddiqui SI, Allehyani ES, Al-Harbi SA, Hasan Z, Abomuti MA, Rajor HK, Oh S. Investigation of Congo red toxicity towards different living organisms: a review. Processes, 2023, 113807

[31] Sudarsan S, Murugesan G, Varadavenkatesan T, Vinayagam R, Selvaraj R. Efficient adsorptive removal of congo red dye using activated carbon derived from Spathodea campanulata flowers. Sci Rep, 2025, 1511831

[32] Vignesh V, Shanmugam G. Removal and recovery of hazardous congo red from aqueous environment by selective natural amino acids in simple processes. Process Biochem, 2023, 127: 99-111.

[33] Zhuo R, Fan F. A comprehensive insight into the application of white rot fungi and their lignocellulolytic enzymes in the removal of organic pollutants. Sci Total Environ, 2021, 778: 146132.

Funding

Indian Council of Medical Research

Rights & permissions

Jiangnan University