Production of cellulase/β-glucosidase by the mixed fungi culture Trichoderma reesei and Aspergillus phoenicis on dairy manure

Abstract

Trichoderma reesei was co-cultured with Aspergillus phoenicis using dairy manure as a substrate to produce cellulase with a high level of β-glucosidase. For pure cultures of T. reesei and A. phoenicis, the optimal media compositions were the same (10 g/L manure supplemented with 2 g/L KH 2PO 4, 2 mL/L tween-80 and 2 mg/L CoCl 2), while the optimal temperature and pH were similar (25.5 °C and pH 5.76 for T. reesei; 28.2 °C and pH 5.14 for A. phoenicis). The mixed culture was therefore completed at 27 °C and pH 5.5, which is close to the optimal values for both fungi. The mixed culture resulted in a relatively high level of total cellulase and β-glucosidase. It was also found that a high manure solid concentration (>20 g/L) resulted in higher enzyme activities, probably due to an alleviation of the nutrients limitation at 10 g/L manure. The β-glucosidase activity and filter paper activity of the mixed fungi culture were 0.64 IU/mL and 1.54 FPU/mL, respectively, corresponding to a ratio of 0.41, which is an ideal ratio for hydrolyzing manure cellulose. To test the effectiveness of the enzymes produced by mixed culture, a crude enzyme broth was used for hydrolyzing the manure cellulose. The glucose concentration produced was significantly ( p < 0.01) higher than the glucose obtained when using the commercial enzyme and the enzyme broth of the pure culture T. reesei. The results indicate that the mixed culture of T. reesei and A. phoenicis is an effective approach to produce a cellulolytic enzyme system for hydrolyzing manure cellulose.