Production of feed enzymes from citrus processing waste by solid‐state fermentation with Eupenicillium javanicum

Abstract

SummaryBingtang sweet orange processing waste was utilised to produce four feed enzymes (Endoglucanase, β‐glucosidase, pectinase and xylanase) by the solid‐state fermentation (SSF) with Eupenicillium javanicum. The factors related with SSF including moisture content, temperature, initial pH, time, carbon source (0.5 g), nitrogen sources (0.05 g), inorganic mineral salts (0.1 g) were investigated separately. The corresponding optimal condition was: moisture content 80% (w/w), temperature 30 °C, natural pH, time 96 h, wheat bran 0.5 g, (NH4)2SO4 0.05 g or NaNO3 0.05 g, CaCl2 0.1 g. The L9(34) orthogonal experiment results showed that the optimal condition for producing above multiple enzymes was: moisture content 80% (w/w), temperature 30 °C, wheat bran 1 g, (NH4)2SO4 0.05 g, NaNO3 0.05 g, CaCl2 0.1 g, fermentation time 96 h and natural pH. Under this condition, the average activity of Endoglucanase (CMCase), β‐glucosidase, pectinase and xylanase by E. javanicum could reach 46.80, 49.64, 51.87 and 106.42 U g−1, respectively, which was significantly higher than those in single factor experiments. Our present results demonstrated that E. javanicum could also be an effective and useful fungus for multienzyme preparation especially for β‐glucosidase and xylanase from citrus processing wastes.