Extraction, enzymatic properties and application of laccase from Pleurotus citrinopileatus residue

ObjectiveExplore a low-cost laccase preparation method that can be used for juice clarification.MethodsThe extraction method, optimal reaction conditions and preparation conditions of enzyme powder were optimized, and the prepared laccase powder was applied to blueberry juice clarification.ResultsThe optimal extraction conditions for laccase were as follows: citric acid buffer with pH 4.8, solid-liquid ratio of 1∶5 (g/mL), extraction temperature of 50 ℃, and extraction time of 4 h. The optimal conditions for laccase reaction were as follows: reaction temperature 30 ℃, pH 4.8, Cu2+ concentration 10 mmol/L, Mn2+ concentration 5 mmol/L. The optimal conditions for the preparation of enzyme powder were as follows: maltodextrin and skimmed milk powder were mixed as drying aids according to the mass ratio of 1∶1, the air inlet temperature was 140 ℃, and the feed flow rate was 160 mL/h. The degradation rate of total phenols of blueberry was as high as 63.5% under the conditions of laccase dosage of 6 U/10 mL, enzymatic hydrolysis temperature of 55 ℃ and enzymatic hydrolysis time of 120 min.ConclusionLaccase extracted from the residue of Ulmus lum mushroom using an optimal process can be used for the clarification of blueberry juice.