Investigating the Biotechnological Potential of some Marine-Derived Fungal Strains with Laccase-Like Activity to Degrade Textile Dyes.

The complex structure of synthetic dyes has made them challenging to decolorize, despite their widespread use in a variety of industries, including textiles, cosmetics, printing, paper, and pharmaceuticals. Novel techniques, such as biotechnological methods utilizing enzymes like oxidoreductases and peroxidases, have been used. An affordable and environmentally friendly solution to the issue of decolorizing commercial dyes is the use of oxidative enzymes, such as laccases derived from fungi. This study screened marine-derived fungal strains isolated from five coastal areas in Lagos, Nigeria, in order to identify laccase-like activities and assess the isolates' ability to decolorize industrial dyes. After several steps of culturing on potato dextrose agar (PDA) plates, forty pure fungal cultures were isolated from a total of 100 samples (wood, nets, plants, clothing materials, soil, and water) collected from five different marine biotopes in Lagos: Oniru Beach, Makoko Lagoon, Elegushi Beach, Adekunle Lagoon, and Unilag waterfront. Through preliminary oxidative ability screening with 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), eleven isolates were discovered. Six strains of Meyerozyma guilliermondii , two strains of Rhodotorula mucilaginosa , one strain of Candida tropicalis , and two strains of Penicillium oxalicum were identified as belonging to the following species by means of molecular-based taxonomic approaches. Meyerozyma guilliermondi A4B, one of these isolates, showed the greatest degree of oxidative ability and decolorized four synthetic dyes from different dye families. Meyerozyma guilliermondii A4B grew best under 2 mM CuSO ₄ as an inducer and 2 percent NaCl to mimic a marine environment, and produced the highest laccase-like active cell-free supernatants activity.