Expression of the genes coding for the xylanase Xys1 and the cellulase Cel1 from the straw-decomposing Streptomyces halstedii JM8 cloned into the amino-acid producer Brevibacterium lactofermentum ATCC13869

The xylanase (xysA) and the cellulase (celA1) genes from Streptomyces halstedii JM8 were cloned into Escherichia coli/Brevibacterium lactofermentum shuttle vectors and successfully expressed in both hosts when placed downstream from the kanamycin resistance promoter (Pkan) from Tn5 but not when under the control of their own promoters. Xylanase was secreted into the culture media of B. lactofermentum by removal of the same leader peptide as is removed in S. halstedii. The main difference between the production of xylanase by Streptomyces and corynebacteria was the low level of processing of the mature extracellular xylanase by B. lactofermentum, probably due to the lack of protease activity in this microorganism.