Purification and characterization of a novel poly(butylene succinate)-degrading enzyme from Aspergillus sp XH0501-a

A poly(butylene succinate) (PBS)-degrading Aspergillus sp. XH0501-a was obtained by ultraviolet light compound LiCl mutagenesis from the Aspergillus sp. XH0501 which was isolated from soil. The enzymatic activity of strain XH0501-a was 38.89% higher than that of the wild-type strain. A novel extracellular PBS-degrading enzyme with a molecular weight of 44.7 kDa was purified to homogeneity from the culture supernatant of XH0501-a strain. The optimum temperature and pH for the enzyme activity was 40A degrees C and pH 8.6, respectively. It was found that Fe2+ and Ca2+ enhanced the enzyme activity, whereas Cu2+ and Hg2+ inhibited it. The primary products after enzymatic degradation were identified by mass spectrometric analysis and the results indicated that the enzyme was of the exo-type and cut the chain from the carboxyl end; the affinity for the substrate was relative to the chain length of the carboxylic ester.