Improving Specific Activity of Aspergillus carbonarius Polygalacturonase Using Polymeric Membranes

Abstract

Microfiltration (MF) and ultrafiltration (UF) membranes were screened for improving the specific activity of polygalacturonases (PG) in the culture broth of Aspergillus carbonarius obtained after submerged fermentation. While 200 and 450 nm MF membranes eliminated some of the larger non-enzymatic proteins, 50 kDa UF membrane exhibited a marginal selectivity between the enzyme and other smaller proteins. The 450 nm MF and 50 kDa UF membranes selected were further evaluated under different process conditions for an integrated membrane process. The process efficacy of three different schemes was also studied for enzyme purification. A two-stage membrane process employing MF followed by UF improved the enzyme-specific activity (5,590 U/mg) by 4.69-fold eliminating the larger and smaller non-enzymatic proteins as well as non-protein impurities with a recovery of 76% enzymes, besides resulting in higher productivity. Thus, adoption of integrated membrane process with appropriate selection of membranes could result in high recovery of enzymes with improved specific activity.

Downstream processing of pectinase produced by Aspergillus niger in solid state cultivation and its application to fruit juices clarification

“…Thus, in our test, enzymes and other proteins with molecular weight above 10 kDa were retained in the concentrate stream and this could explain the low fold purification attained (4.07). This result is in accordance with those of other works that reported values of 5.14 and 7.7 fold purification using membranes with 50 kDa and 10 kDa, respectively (Nakkeeran et al, 2008;Silva et al, 2007). However, the fold purification could be a relatively unimportant parameter for the evaluation of an enzyme recovery method, since the desirable purity degree of a preparation depends on the application.…”

Activated charcoal and microfiltration as pretreatment before ultrafiltration of pectinases produced by Aspergillus niger in solid-state cultivation

“…This turbidity can be related with gummy polysaccharides and pigments that are extract from the cultivated medium as described by Singh et al [20], and could interfere in the concentration process. Nakkeeran et al [5], in the MF step eliminated 45% and 23% of proteins and carbohydrates, respectively, but the polygalacturonases activity recovery was 85%, while in this work the recovery was higher than 90%.…”

“…During the UF was also possible to remove about 95% of carbohydrates. Nakkeeran et al [5], reported the polygalacturonase retention of 93% with a 50 kDa membrane. The 10 kDa membrane used in this work seems to be appropriate to avoid enzyme losses in the permeate stream.…”

Effect of stirring and pump on membrane processing of Aspergillus carbonarius culture broth for polygalacturonase

“…Porous membranes have been employed generally for the concentration of enzymes and only a few reports describe purification of microbial pectinases using membranes [1,2]. In our earlier study, an integrated membrane process employing microfiltration (MF) and ultrafiltration (UF) membranes was proposed for processing submerged fermentation (SmF) polygalacturonase (PG) which enhanced the specific activity to 5590 U/mg (4.69-fold increase) with a recovery of 76% and almost completely eliminated the non-protein impurities including carbohydrates [3]. In another study, desalting and concentrating eluted solid-state fermentation (SSF) PG using a 10 kDa UF membrane resulted in a low PG recovery of 36% at 800 rpm (30 • C; 5 h) in a stirred membrane cell [4].…”