In-vitro Evaluation of Synthetic Dye Decolourisation by Filamentous Ascomycetous Fungi Isolated from Freshwater Environments in Sri Lanka and Development of a Prototype for Addressing Environmental Pollution from Synthetic Dye Contamination

Madhara K. Wimalasena^1,2,3Nalin Nilusha Wijayawardene^1,2,4Susan B. Dharmarathne²Nimesha Gunasekara²Manavi S. Ekanayake⁵R.G. Udeni Jayalal⁶JAYARAMA DARBHE BHAT^7,8,9TURKI ALDAWOUD⁷Zhang Guiqing^1,10,11Damith C. Weerasinghe¹²H. K. S. de Zoysa²Dong-Qin Dai^1*Haohan Wang^1*Thushara Chathuranga Bamunuarachchige^2*

• ¹Center for Yunnan Plateau Biological Resources Protection and Utilization, Qujing Normal University, Qujing, Yunnan Province 655011, China
• ²Department of Bioprocess Technology, Faculty of Technology, Rajarata University of Sri Lanka, Mihintale 50300, Sri Lanka
• ³Faculty of Graduate Studies, Sabaragamuwa University of Sri Lanka, Belihuloya 70140, Sri Lanka
• ⁴Tropical Microbiology Research Foundation, 96/N/10, Meemanagoda Road, Pannipitiya 10230, Sri Lanka
• ⁵Department of Aquaculture and Fisheries, Faculty of Livestock, Fisheries and Nutrition, Wayamba University of Sri Lanka, Makandura, Gonawila, 60170, Sri Lanka
• ⁶Department of Natural Resources, Faculty of Applied Sciences, Sabaragamuwa University of Sri Lanka, Belihuloya 70140, Sri Lanka
• ⁷Department of Botany and Microbiology, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
• ⁸Biology Division, Vishnugupta Vishwavidyapeetam, Ashoke, Gokarna 581326, India
• ⁹Formerly, Department of Botany, Goa University, Goa 403206, India
• ¹⁰Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand
• ¹¹Center of Excellence in Microbial Diversity and Sustainable Utilization, Chiang Mai University, Chiang Mai 50200, Thailand
• ¹²Department of Materials Technology, Faculty of Technology, Rajarata University of Sri Lanka, Mihintale 50300, Sri Lanka

Mycoremediation emerges as an alternative strategy for decolourisation of synthetic dyes and is valued for its cost-effectiveness and environmentally friendly attributes. Five fungal strains, Aspergillus sp.1, Lasiodiplodia crassispora, L. pseudotheobromae, Neopestalotiopsis saprophytica, and Trichoderma sp.1, isolated from freshwater environments in Sri Lanka, were subjected to decolourisation of 100 mg L-1 of Congo Red (CR), Crystal Violet (CV), Malachite Green (MG), and Safranin dyes, frequently discharged into the environment from laboratories and industries. Screening of the decolourisation ability of isolated fungal strains was conducted in both solid and liquid media containing Potato Dextrose Agar (PDA) and Potato Dextrose Broth (PDB) for ten days incubation period and 14–28 days, respectively, at 30 °C. The liquid media screening processes showed that L. pseudotheobromae exhibited the highest decolourisation percentage for CV (95.23% ± 0.82) and MG (93.12% ± 0.36). L. crassispora demonstrated the highest decolourisation abilities for CR (91.45% ± 0.20) and Safranin. All fungal strains successfully achieved over 60% decolourisation of CV, CR, and MG. However, Safranin showed the lowest decolourisation by all isolated strains, except for L. crassispora (70.46% ± 1.18). Considering the overall results in both solid and liquid media (exceeding 70%), L. crassispora exhibited the highest decolourisation ability among all selected dyes. Besides, the results in liquid media were reconfirmed by the screening process on solid media. The results of the present study showed that mycoremediation for synthetic dye decolourisation should be expanded to outdoor settings. Leveraging this insight, a prototype was developed for real-world application, creating a microencapsulation system for mycoremediation. This innovative system offers a sustainable alternative to traditional physicochemical treatments for wastewater management, specifically on laboratory discharges.