Removal pattern of vinasse phenolics by Phlebia rufa, characterization of an induced laccase and inhibition kinetics modeling

• Published in: Biodegradation (Dordrecht) 2021-06, Vol.32 (3), p.287-298
• Main Authors: Fernandes, Joana M. C., Fraga, Irene, Bezerra, Rui M. F., Dias, Albino A.
• Format: Article
• Language: English
• Subjects: Acids; Aerobic conditions; Analysis; Aquatic Pollution; Aromatic compounds; Biodegradation; Bioflavonoids; Biomedical and Life Sciences; Chlorides; Constants; Distillation; Distilling; Enzyme inhibitors; Flavones; Flavonoids; Fluorides; Geochemistry; High-performance liquid chromatography; Homogeneity; HPLC; Hydroxycinnamic acid; Inhibitors; Kinetics; Laccase; Life Sciences; Liquid chromatography; Microbiology; Molecular weight; Original Paper; Oxidases; Oxidation; p-Hydroxybenzoic acid; pH effects; Phenolic compounds; Phenols; Soil Science & Conservation; Sulfonic acid; Temperature effects; Terrestrial Pollution; Vinasse; Waste Management/Waste Technology; Waste Water Technology; Wastewater; Water Management; Water Pollution Control
• ISSN: 0923-9820; 1572-9729
• DOI: 10.1007/s10532-021-09936-z

Vinasse from the distillation of winemaking residues is a wastewater characterized by high levels of aromatic compounds. Batch cultures of Phlebia rufa showed a significant (p < 0.05) correlation between laccase activity and initial vinasse concentration. The pattern of biodegradation of hydroxybenzoic acids, hydroxycinnamic acids and flavonoids, assessed by HPLC-DAD, revealed that p -hydroxybenzoic acid is the most recalcitrant compound. Vinasse-induced laccase showed electrophoretic homogeneity and molecular weight of 62 kDa after being purified 21-fold. Optimum pH for oxidation of 2,6-dimethoxyphenol (2,6-DMP) was 3.5 and optimum temperature was 50 °C, with an activation energy of 42.8 kJ mol −1 . Catalytic efficiency of 2,2′-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) oxidation is about two orders of magnitude higher than 2,6-DMP oxidation, being their K m values 36.2 ± 2.6 μM and 303.0 ± 44.7 μM, respectively and k cat values 486.1 s −1 and 179.6 s −1 , respectively. Akaike information criterion and Akaike weights were used to discriminate inhibition models that best fitted 2,6-DMP oxidation in the presence of inhibitors. Inhibition constants of mixed-type inhibitors azide and fluoride, and competitive-type inhibitor chloride, showed the following inhibitors potency: azide > fluoride > chloride. Taken together, this study is consistent with the assumption that P. rufa could be a useful tool for aerobic degradation of phenolic-rich wastewaters.