Production and separation of α-agarase from Altermonas agarlyticus strain GJ1B

Abstract

This paper presents results on the production of α-agarase by a fermentation process and its separation using membrane microfiltration (MF). Optimization of fermentation conditions for α-agarase production using Altermonas agarlyticus grown on medium containing agar as a carbon source was done in batch, fed-batch and continuous fermentations. Continuous culture at a dilution rate of 0.03 h −1 appeared to be best suited for production of α-agarase by this organism. At 0.03 h −1 dilution rate, enzyme activity was 0.9 U/ml. Clarification of broth was done using a hollow-fibre microfiltration membrane. The influence of hydrodynamic parameters on permeate flux and enzyme activity was studied. The best performance was obtained with prefiltered fermentation broth. A stable permeate flux of about 250–270 ml/min·m 2 and an enzyme retention rate between 0% and 25% was obtained at temperatures between 6°C and 22°C, transmembrane pressure of 100 mm Hg and fluid cross-flow velocity of 4×10 −2 m/s. From the experiments on concentration of fermentation broth, the best compromise between enzyme activity transmission and permeate flux was obtained at a concentration factor of 2.