Volume 62, Issue 340, January - April 2026

Optimisation of laccase production by Curvularia verruculosa UDY through solid-state fermentation using response surface methodology

Samuel Adedayo Fasiku^1♦, Atilade Amos Oladunni², Taiwo Bukola Fasiku³, Godswill Uduak Ernest¹, Opeyemi Janet Adeogun¹, Femi Johnson Afolabi¹

¹Department of Microbiology and Biotechnology, Ajayi Crowther University, Oyo-Town, Nigeria
²Department of Chemical and Petroleum Engineering, Abiola Ajimobi Technical University, Ibadan, Nigeria
³Department of Physics, Ajayi Crowther University, Oyo-Town, Nigeria

^♦Corresponding Author
Samuel Adedayo Fasiku, Department of Microbiology and Biotechnology, Ajayi Crowther University, Oyo-Town, Nigeria

ABSTRACT

Laccases are multicopper oxidase enzymes with significant industrial and environmental applications, including bioremediation, textile dye degradation, and biosensor development. This study aimed to optimise laccase production under solidstate fermentation using Response Surface Methodology (RSM) and to utilise the produced laccase for dye decolourisation. The laccase-producing fungus was molecularly identified. Parameters, including incubation period, pH, substrate concentration, inoculum size, and carbon sources, were optimised using RSM. The model equation was generated using Design Expert, and the model's statistical significance was evaluated using analysis of variance (ANOVA). Laccase was quantified using 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) as a substrate. The effect of environmental conditions on laccase activity was determined, and the enzyme was used to decolourise dyes. The laccase-producing fungus was identified as Curvularia verruculosa UDY (accession number PV669996). The optimum laccase yield (735 μU/L) was observed with sugarcane bagasse as the substrate on a basal medium containing a glucose carbon source, at an initial pH of 3, with an inoculum size of 2 fungal plugs, over a fermentation period of 10.5 days. All cations tested enhanced laccase activity, with Mn²⁺ producing the greatest stimulation (1056 μU/mL). At various pH levels, the highest laccase activity (898 μU/mL) of C. verruculosa UDY was observed at pH 9.5, while activity at different temperatures peaked (943 μU/mL) at 60°C after 40 min. Laccase decolourised Congo red by 22% within 2 hours. The production of laccase by C. verruculosa UDY through solid-state fermentation was optimised. Cations, pH, temperature, and time affected laccase activity, and the produced laccase decolourised dyes, which could promote the utilisation of agrowastes for industrial enzyme production as well as laccase decolourisation application in the textile industry.

Keywords: Dye decolourisation, Fungi, Lignin-degrading enzyme, Microbial fermentation, Sugarcane bagasse

Discovery, 2026, 62, e7d3235

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Published: 16 March 2026