2.5 Hydrolysis enzymatic synthesis and fermentation
Enzyme reactions were performed based on the conditions in Table 3. Furthermore, reaction conditions were investigated, including temperature, pH value, buffer type, concentration, and the Ps XR and Pd PDHD36A/I37R ratio, as shown in Figure S1. WP was hydrolyzed in citrate buffer at pH 5.5, 55 °C with a suitable amount of β -galactosidase. Enzymatic hydrolysis was performed in a conical flask containing 122 g/L WP or 100 g/L lactose, 50 mM citrate buffer (pH 5.5, 55 °C), and a suitable amount of β -galactosidase for 3 h. Enzymatic synthesis and fermentation were performed in a conical flask containing previously obtained enzymatic hydrolysates, 100 mM Tris-HCl buffer (pH 8.0, 30 °C), suitable amounts ofPd PDH-Ps XR complex, cofactor NADPH, and yeast cells with a final A600 = 1. For the fermentation of enzymatic hydrolysates derived from lactose, 2% tryptone was required. The protein content of the WP solution and yeast cells was determined using a BCA Protein Assay Kit, as previously reported.[14]