Experimental design and response surface modeling applied for the optimisation of pectin hydrolysis by enzymes from A. niger CECT 2088

Optimisation of pectin hydrolysis using pectolytic enzymes produced by Aspergillus niger CECT 2088 was carried out. The effect of enzyme concentration (0.018–0.072%, w/v), substrate concentration (0.004–0.896%, w/v), pH (4.49–5.91), temperature (32.2–67.8 °C) and reaction time (18.2–71.8 min) on the enzymatic process was studied. The experiments were arranged according to a central composite statistical design. Response surface methodology (RSM) was used to assess factor interactions and empirical models regarding four product response variables (i.e., reactor conversion, reducing sugar concentration, endopectolytic productivity and enzymatic depolymerization productivity). Multi-response optimisation was also performed on the reactor and endopectolytic productivity data set of the factorial design. The highest reactor conversion (61%) and endopectolytic productivity (7.2 cSt mg⁻¹ ml⁻¹) were achieved with 1 h reaction time at 46 °C and pH 4.8 at a substrate/enzyme ratio of 11.6.