Purification and biochemical characterization of extracellular glucoamylase from Paenibacillus amylolyticus strain.

In the present study, glucoamylase produced from a soil bacterium Paenibacillus amylolyticus NEO03 was cultured under submerged fermentation conditions. The extracellular enzyme was purified by starch adsorption chromatography and further by gel filtration, with 2.73-fold and recovery of 40.02%. The protein exhibited molecular mass of ∼66,000 Da as estimated by SDS-PAGE and depicted to be a monomer. The enzyme demonstrated optimum activity at pH range 6.0-7.0 and temperature range 30-40 °C. Glucoamylase was mostly activated by Mn metal ions and depicted no dependency on Ca ions. The enzyme preferentially hydrolyzed all the starch substrates. High substrate specificity was demonstrated towards soluble starch and kinetic values K and V were 2.84 mg/ml and 239.2 U/ml, respectively. The products of hydrolysis of soluble starch were detected by thin layer chromatography which showed only -glucose, indicating a true glucoamylase. The secreted glucoamylase from P. amylolyticus strain possesses properties suitable for saccharification processes such as biofuel production.