Identification and characterization of a novel glucomannanase from Paenibacillus polymyxa

Konjac glucomannan oligosaccharide has attracted much attention due to its broad biological activities. Specific glucomannan degrading enzymes are effective tools for the production of oligosaccharides from konjac glucomannan. However, there are still few reports of commercial enzymes that can specifically degrade konjac glucomannan. The gene ppgluB encoding a glucomannanase consisting of 553 amino acids (61.5 kDa) from Paenibacillus polymyxa 3-3 was cloned and heterologous expressed in Escherichia coli BL21 (DE3). The recombinant PpGluB showed high specificity for the degradation of konjac glucomannan. Moreover, the hydrolytic products of PpGluB degrade konjac glucomannan were a series of oligosaccharides with degrees of polymerisation of 2-12. Furthermore, the biochemical properties indicated that PpGluB is the optimal active at 45 to 55 °C and pH 5.0-6.0, and shows highly pH stability over a very broad pH range. The present characteristics indicated that PpGluB is a potential tool to be used to produce oligosaccharides from konjac glucomannan.