Boldly going green: utilizing Pycnoporus sp. for laccase production and sustainable vinasse treatment

PABLO MIGUEL AHMED; ÁLVAREZ, ANALÍA; FIGUEROA, LUCÍA INÉS CASTELLANOS DE; PAJOT, HIPOLITO FERNANDO

International Journal of Environmental Science and Technology

Institute for Ionics

Año: 2023 vol. 21 p. 3927 - 3942

Sugarcane vinasse is a highly polluting residue generated from bioethanol production. Currently, vinasse is either used in fertigation or treated anaerobically, but these methods have limitations. However, fungal bioconversion offers a potential solution by transforming vinasse into valuable products, such as industrial enzymes. In this study, we evaluated the efficiency of Pycnoporus strain sp. P6 in laccase production and vinasse biodegradation through submerged fermentation and solid-state fermentation. We also investigated the effects of sugar supplementation during the immobilization stage, reuse of immobilized biomass, and phytotoxicity of treated and untreated vinasse on Lactuca sativa seeds. The results showed that Pycnoporus sp. strain P6 effectively treated vinasse in liquid cultures, reducing its color, phenolic compounds, toxicity, and oxygen demands. Immobilized biomass significantly improved all tested parameters, while glucose supplementation during immobilization resulted in laccase titers exceeding 700 U/L. This approach also led to reductions of 35% in color, 55% in phenols, and over 69% in oxygen demands. Furthermore, the use of immobilized mycelium further increased laccase activity by 300%, resulting in over 30% reduction in color, a 58% reduction in phenols, and a 48% reduction in oxygen demands. These findings suggest that Pycnoporus sp. strain P6 could be utilized for vinasse detoxification. Moreover, properly diluted treated vinasse promoted plant growth, supporting its use in fertigation. The proposed system is simple, reproducible, environmentally friendly, and cost-effective, making it a promising alternative for the final disposal of vinasse.