â-Mannanase from Penicillium oxalicum SO efficiently hydrolyzed guar galactomannan to galactomanno-
oligosaccharides. Gel filtration estimated the molecular weight of the â-mannanase as 35 000
and SDS-PAGE as 29 000. The optimum pH was around 5 while a stable pH was reached in the
range of 3-6. Optimum temperature was around 60 °C at pH 5, while under 60 °C activity was
stable. HPLC analysis detected oligosaccharides with degrees of polymerization (DP) of 2 to 7 and
2 to 6 released on hydrolysis of guar and locust bean gums, respectively; about 92% of the released
sugars were oligosaccharides. In analysis of the sugar distribution on MALDI-TOF-MS, major products
of DP 6 and 7 and DP 5 and 6 were confirmed in hydrolysates of guar gum and locust bean gum,
respectively. One of the main oligosaccharides released from guar gum, with DP 7, had a high
galactose content (Gal/Man ) 0.76) and corresponded to a blockwise galactose-substituted mannan
type in galactomannan.