Isolation of Klebsiella pneumoniae Producing Pullulanase and Its Enzymatic Characterization

A pullulanase producing bacterium,designated strain GXAS 38,was isolated from samples collected from the waste lagoon of a starch factor in Nanning,Guangxi.Strain GXAS 38 was identified as Klebsiella pneumoniae based on morphological,physiological characterization and 16S rDNA sequences analysis.The optimum temperature and pH for the enzyme were determined as 60℃ and 5.5,respectively.The stable temperature and pH range were 35~50℃ and 5.0~7.5,respectively.The enzyme could be stimulated by Ca2+,Na+ and Li+,but inhibited by Cu2+,Zn2+,Co2+,Mn2+,Fe2+,Fe3+,Ba2+ and EDTA.The pullulanase gene was amplified by PCR and sequenced.The full length of this gene was 3291 bp and presumably encoded 1096 amino acids.