Preparation and properties of adsorption material from corn stalks core when used for enzyme immobilization and the subsequent activities of the adsorbed enzymes

This study investigates the characteristics of core adsorption material (CAM) prepared from corn stalks core (Core) by glycol solvent treatment (high pressure boiling at 120 degrees C for 30 min using a 50:3 liquor/solid ratio with 2%, w/w sodium hydroxide). The structures of CAM and Core were compared by FT-IR, SEM and XRD. Maltogenic amylase from Aspergillus awamori var., neutral proteins from Source Organism and lipase from Pseudomonas aeruginosa were selected as model enzymes in order to assess their potential applicability for enzyme immobilization. Adsorption characteristics for the different enzymes on CAM were studied and the activity of the immobilized enzymes was evaluated. The results show that CAM has many hydroxyl groups, more flakes, irregular indentations and grooves and a proportionally larger amount of hemi-cellulose than Core, which results in increased numbers of hydroxyl groups in CAM and increased enzyme accessibility into CAM; CAM has the greatest adsorption capacity (9.84 +/- 0.32 mg/g) for neutral proteins and the best relative activity (total relative activity of 212.6% after being reused three times) after being immobilized, as well as the lowest adsorption capacity (5.15 +/- 0.51 mg/g) for lipase and the lowest relative activity (total relative activity is 78.23%). The isotherms of maltogenic amylase and neutral proteinase were found to be linear using the Langmuir equation (R-2 = 0.9974 and 0.9966, respectively, p<0.0001) and lipase was found to be linear using the Freundlich equation (R-2 = 0.9331, p<0.0075) in the studied concentration range; CAM could adsorb neutral proteinase and could be used in the simple and inexpensive production of large quantities of pure industrial neutral proteinase and Core can be used to prepare CAM. (C) 2013 Elsevier B.V. All rights reserved.