Coexpression of rumen fungal xylanase and bifunctional cellulase genes in Escherichia coli

ABSTRACT Rumen fungi inhabit the gastro-intestinal tract of ruminants and the most non-ruminant herbivores. Rumen fungi produce highly active plant cell wall degrading enzymes, therefore they have gained scientific interest. In this study, genes encoding xylanase (xynA-7) and cellulase (celA-5) were amplified from Neocallimastix sp. GMLF7 and Orpinomyces sp. GMLF5, respectively, and expressed in Escherichia coli. XynA-7 was found to be active only on xylan, however CelA-5 had activity both on carboxymethyl cellulose and lichenan. Lichenase activity of CelA-5 was found to be higher than carboxy...