Purification of polygalacturonase from solid-state cultures of Aspergillus carbonarius

Purification of polygalacturonase (PG) from the cultures of Aspergillus carbonarius obtained by acetate buffer extraction after solid-state fermentation was attempted by integrated membrane process and alginate affinity precipitation. The carbohydrates were completely eliminated (98%–99%) with a PG recovery of 72%–80% during integrated membrane process, which would otherwise interfere with the purification process and lead to enzyme loss. However, specific activity of PG did not improve (1.19–1.21 fold) due to the presence of other similar molecular mass proteins. Under optimum conditions of affinity precipitation, the specific activity of PG enhanced to 2450 U/mg (4 fold) with almost complete elimination of carbohydrates and colour compounds resulting in a PG recovery of 61%. PG purity obtained with ultrafiltration (UF) was comparable with the conventional dialysis during desalting eluted PG, besides UF rendered a concentrated PG. The enzyme purity stated was as descend by SDS–PAGE. The results suggested suitability of affinity precipitation for PG purification from solid-state cultures and the potential of UF as a single step process for handling eluted PG.