Cloning and Characterization of Cellulase and Xylanase Coding Genes from Anaerobic Fungus Neocallimastix sp. GMLF1

An anaerobic fungus was isolated from the cattle feces and identified as Neocallimastix sp. by using morphological approaches. Cellulase, xylanase, p-xylosidase and p-glucosidase production were assayed from culture supernatants and maximal activities were found 6.99, 10.68, 2.72 and 3.24 U/mL, respectively. Cellulase and xylanase coding genes were isolated by using polymerase chain reaction and expressed in E. coli. Nucleotide sequencing showed that the cel1A (1367 bp) and xyn1B (992 bp) had open reading frames encoding polypeptides of 393 and 259 amino acids, respectively. Cel1A showed highest activity on lichenan and followed by carboxymethyl cellulose but Xyn1B was found to be only active on xylan. The optimal conditions were pH 6.0 for Cel1A and pH 6.5 for Xyn1B and 50oC for both enzymes. The enzymes were stabile at 40-50oC but readily inactivation occurred at 60oC. Cel1A activity was enhanced more than 50% in the presence of 1 mM MnCl2, CoCl2 and dithiothreitol, however the same effect was only recorded for Xyn1B with MnCl2. Application studies showed that Cel1A was found to be active on cereal grains such as barley and oat. Bio-bleaching trials by using Xyn1B reduced the kappa numbers of wheat straw and eucalyptus kraft pulps. © 2010 Friends Science Publishers