Modeling of neoagarobiose production by enzymatic hydrolysis of agarose

Abstract

An experimental and modelling study has been done for the hydrolysis of agarose to produce ne-oagarobiose by using a mixture of two different ß-agarases: AgaG1 screened from Alteromonas sp. GNUM1; and DagB from Streptomyces coelicolor A3(2). Experiments based on the central compo-site design (CCD) were carried out for various combinations of the amounts (or activity levels) of these two enzymes in the solution. Based on the experimental data, quadratic models or response surfaces quantitatively describing the effects of both enzymes on the volumetric productivity have been developed. The reference activity levels of AgaG1 and DagB for the CCD were identified when the reaction time was 12 hrs. In the case of DagB, 0.1 U/mL was enough to completely hy-drolysis of 10 g/L agarose in 12 hours, and in case of AgaG1, 0.7 U/mL was enough. The first-round CCD experiments with these reference points gave a model equation of y = 0.69 + 0.17A + 0.081B - 0.047A2 + 0.057AB, where y, A, and B denoted the productivity, the activity of AgaG1, and the activity of DagB, respectively. Its validity was confirmed by ANOVA. The second-round CCD experiments based on 6 hours of reaction gave a model of y = 0.93 + 0.26A + 0.157B + 0.14AB.