Abstract:The changes of molecular weight parameters of alginates hydrolyzed by alginate lyase (ALyase) and cellulase using one-step and step-by-step methods were studied by GPC-MALLS. The chain shear models and the degradation conditions were determined. The results showed cellulase had no function on alginate if used alone. Multiple shear model and central shear model were observed when alginate lyase used. Furthermore, the utilization rate was improved with the step-by-step method of alginate lyase. The duration of one-step and step-by-step degradation using 2.56~10.24 U/mg alginate lyase were with in 2 h and 5 h, respectively. The synergistic effect of alginate lyase with cellulase was further explored by step-by-step method at 0 min (iACS), 30 min (iACM), 60 min (iACE). Alginate lyase preferred to take effect on the alginates of molecular weight (Mw)≥1×105, while cellulase preferred to 1×104~1×105 g/mol. The PDI values were stable and approached to 2 infinitely in the iACE method, showing a random shear model. In the iACS and iACM methods, the hydrolyzed products varied in components with increased molecular weight, and their PDI values rose to 5.14 and 7.02 respectively.
