Primary isolation of Geotrichum klebahnii polygalacturonase by capturing with glass fiber microfilters

This study reports the use of borosilicate glass fiber microfilters (GFMs) for capturing and concentrating Geotrichum klebahnii polygalacturonase (GkPG) from the culture media through a simple coupled filtration–sorption process. GFM was characterized by scanning electron microscopy and intrusion mercury porosimetry. Adsorption of GkPG was almost instantaneous with maximum effectiveness at pH 3.0. Using the parameters of Langmuir model and a material balance, a filter bed consisting of a stack of GFM was designed for recovering GkPG from a certain volume of culture media. After adsorption and washing, the enzyme was efficiently eluted with a buffer solution at pH 5.0 containing 0.5 M NaCl. The filter bed was reused in several sorption cycles and enzyme recovery could be also done without prior cell removal with the benefits of using microfiltration for enzyme cell separation in a single step. Under the process conditions employed, GkPG recovery was about 80% with a concentration factor of about 4-fold.

► Improving the result presentation, especially as regards the supernatant dilutions of the batch culture, now expressed in relation with the original medium and the data of enzymatic activity, protein and conductivity of the solutions used in the studies of the enzyme recovery from the culture medium. ► Highlighting the novel results of this work, specifically the microfilter structural and adsorption characteristics, and the possibility of integrating the enzyme recovery and the biomass separation in a single filtration stage. ► Improving the use of English.