Assessment of Cultivation Parameters Influencing Polygalacturonase Production by Aspergillus sp. SO5 in Submerged Fermentation

Abstract

Polygalacturonase represents an important enzyme of the pectinase consortium in the food and beverage industry. The present study aims to isolate, screen, and enhance physicochemical parameters for enzyme production under submerged fermentation. A total of 34 fungal strains were obtained from rotten fruits and 70.6 % of them are able to produce polygalacturonase by degrading pectin in pectin screening agar. The fungal isolate (SO5) that exhibited the greatest diameter of the hydrolysis zone (45.3 ± 0.04 mm) was selected for further study and later identified as Aspergillus sp. SO5, based on morphological characteristics using light microscopic observation. Several physicochemical parameters improved for pectinase production including incubation temperature, initial pH, agitation speed, inoculum density, and carbon and nitrogen sources. Under improved conditions, the polygalacturonase activity and fungal biomass increased up to 74.63 and 69.44 %, respectively. The finding also revealed that the improved physicochemical conditions enhance enzyme production and shorten the incubation period from 6 days to 5 days. HIGHLIGHTS This research paper highlighted the capability of indigenous fungus (Aspergillus) to produce polygalacturonase. The finding revealed that the improved physicochemical conditions including agitation speed, inoculum size, the concentration of pectin, and incorporation of yeast extract in the culture medium could enhance polygalacturonase production by up to 74.63 % (34.21 ± 0.49 U/mL). The improved physicochemical conditions not only enhance the polygalacturonase production but shorten the incubation period to obtain optimum enzyme production. GRAPHICAL ABSTRACT