Extracellular Production of Klebsiella Pullulanase by Escherichia coli That Carries the Pullulanase Secretion Genes

抄録

The pullulanase gene, pulA, and the genes for pullulanase secretion factors (called the pullulanase secretion genes) from Klebsiella aerogenes were cloned into a cosmid vector, pHC79, in Escherichia coli. Four of one thousand clones isolated secreted pullulanase into their culture broth when the cells were grown with pullulan or maltose. One of the four clones produced much pullulanase extracellularly in a short time, with a level of production eightfold that of the maximum production of the wild-type K. aerogenes W70. Deletion analysis of the recombinant plasmid showed that the pullulanase secretion genes and pulA were all in a 22-kb DNA segment derived from the chromosomal DNA of K.aerogenes.