CHARACTERIZATION OF STREPTOMYCES D3 DERIVED FROM PROTOPLAST FUSION BETWEEN STREPTOMYCES-CYANEUS-190-1 AND STREPTOMYCES-GRISEORUBER-42-9

Streptomyces D3, derived from protoplast fusion between Streptomyces c yaneus 190-1 and Streptomyces griseoruber 42-9, has the ability to pro duce high levels of xylose isomerase when grown on hemicellulosic mate rials such as xylan as the carbon source. Comparison between the parti al nucleotide sequences of the 16S ribosomal RNA genes from S. cyaneus 190-1., S. griseoruber 42-9, and fusant D3 showed that the 16S rRNA g ene of fusant D3 was identical to that of S. cyaneus 190-1. Partial se quence analysis of the xylose isomerase genes also indicated that the gene of fusant D3 was identical to that of S. cyaneus 190-1. The parti al DNA fragments for the xylanase genes (xlnA and xlnB) of fusant D3 w ere amplified by PCR, and subjected to Southern hybridization analysis . The results revealed that the xlnB gene of fusant D3 was similar to that of S. cyaneus 190-1, but that the xlnA gene of fusant D3 was simi lar to that of S, griseoruber 42-9. These results suggest that the maj ority of the genome of fusant D3 may be derived from S. cyaneus 190-1.