Identification of a fungus able to secrete enzymes that degrade regenerated cellulose films and analyses of its extracellular hydrolases

Abstract

The LW03 strain was isolated from Chinese farmland soil and found to be able to secrete certain enzymes degrading regenerated cellulose films at low temperature. The LW03 strain was systematically identified as Rhizopus arrhizus var. arrhizus by morphological, physiological, and molecular methods. Incubation of regenerated cellulose films with the extracted crude enzyme of LW03 was done to measure morphological changes by using scanning electron microscopy. Microscopic observations showed that the morphology of the regenerated cellulose films changed drastically due to enzymatic hydrolysis. The extracellular hydrolases of LW03 strain incubated on bran medium were also assessed. The predominant activity in the crude enzyme was glucoamylase activity, followed by acid proteinase, phytase and pectinase activity. Interestingly, activities of β-glucosidase, endoglucanase, exoglucanase, and cellulase were also observed, but at a much lower extent. Based on initial evidence, the crude enzyme is most likely to contain some new constituents capable of degrading regenerated cellulose films.