Abstract: To simultaneously produce polysaccharides and polypeptides with a higher yield, the enzymatic hydrolysis of Alectryonella plicatula Gmelin was optimized using one-factor-at-a-time (OFAT) method and response surface methodology. Firstly, OFAT experiments were conducted to evaluate the effect of enzyme dosage, hydrolysis time and solid-to-water ratio on the concentrations of polypeptides, total sugar and glycosaminoglycan and the degree of hydrolysis. Then further experiments were designed?by using Design-Expert 8.0.5.0 considering three independent variables each at three levels. Four mathematical models were built using the concentrations of polypeptides, total sugar and glycosaminoglycan and the degree of hydrolysis as responses, respectively. The results showed that the optimal conditions were found to be hydrolysis with 0.2% trypsase (≥ 250 U/mg) for 80 min at a solid-to-water ratio of 1:3 (g/mL). Experiments carried out under these conditions led to a polypeptide concentration of (85.14 ± 1.67)%, total sugar concentration of (28.35 ± 2.72)%, glycosaminoglycan concentration of (1.60 ± 0.10)%, and degree of hydrolysis of (11.12 ± 0.61)%. Good agreement between these values and the model predictions was found, suggesting that the optimized process was feasible. The yields of polypeptides and polysaccharides on a dry basis were (29.39 ± 0.41)% and (36.81 ± 0.47)%, respectively. This study provides a theoretical basis for simultaneous production of polysaccharides and polypeptides from A. plicatula, which will create greater economic benefits for enterprises by comprehensive utilization of A. plicatula.

Key words: Alectryonella plicatula Gmelin, polysaccharides, polypeptides, simultaneous production