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CLONING AND EXPRESSION OF A LIGNIN PEROXIDASE GENE FROM STREPTOMYCES VIRIDOSPORUS IN STREPTOMYCES LIVIDANS
Citation:
Wang, Z., B. Bleakley, D. Crawford, G. Hertel, AND F. Rafii. CLONING AND EXPRESSION OF A LIGNIN PEROXIDASE GENE FROM STREPTOMYCES VIRIDOSPORUS IN STREPTOMYCES LIVIDANS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-92/173.
Description:
A lignin peroxidase gene was cloned from Streptomyces viridosporus T7A into Streptomyces lividans TK64 in plasmid pIJ702. g1II-digested genomic DNA(4-10kb) of S. viridosporus was shotgun-cloned into S. lividans after insertion into the melanin (mel+) gene of pIJ702. ransformants expressing pIJ702 with insert DNA were selected based upon the appearance of thiostrepton resistant (tsr-r)/melcolonies on regeneration medium. ignin peroxidase-expressing clones were isolated from this population by screening of transformants on a tsr-poly B-411 dye agar medium. n the presence of H202 excreted by S. lividans, colonies of lignin peroxidase-expressing clones decolorized the dye. mong 1000 transformants screened, 2 dye-decolorizing clones were found. ne, pIJ702/TK64.1 (TK64.1), was further characterized. k64.1 expressed significant extracellular 2,4-dechlorophenol(2,4-DCP) peroxidase activity (=assay for S. viridosporus lignin peroxidase). nder the cultural conditions employed, plasmidless S. lividans TK64 had a low background level of 2,4 DCP oxidizing activity. K64.1 excreted an extracellular peroxidase not observed in S. lividans TK64, but similar to S. viridosporus lignin peroxidase ALip-P3, as shown by activity stain assays on nondenaturing polyacrylamide gels. he gene was located on a 4 kb fragment of S. viridosporus genomic DNA. hen peroxidase-encoding plasmid, pIJ702.LP, was purified and used to transform three different S. lividans strains (TK64, TK23, TK24), all transformants tested decolorized poly B-411. hen grown on lignocellulose in solid state processes, genetically engineered S. lividans TK64.1 degraded the lignocellulose slightly better than did S. lividans TK64. his is the first report of the cloning of a bacterial gene coding for a lignin-degrading enzyme