Chelate immobilization of amylase on metal ceramic powder: Preparation, characterization and application

The ceramic powder with high metal content (MCP) was prepared as a new kind of immobilization carrier. Cu-MCP showed the best affinity to alpha-amylase and exhibited maximal activity. The effects of metal content, chelation time and amylase concentration on Cu-MCP-amylase activity were investigated. Under the optimal preparation conditions (the ratio of metal hydroxide precipitation to matrix (P/M): 0.23, chelation time: 8 h and amylase solution: 2.2 g/L), the activity of Cu-MCP-amylase could reach 31.5 U/g (54.5% of activity yield). Then, both Cu-MCP and Cu-MCP-amylase were characterized by XRD, SEM, BET-N-2 and FTIR. These characterizations confirmed that the Cu-MCP was a superior carrier with significant mechanical strength, considerable surface area, stable environment, homogeneous surface and low cost. Meanwhile, it also indicated that amylase had been efficiently immobilized on the external surface of Cu-MCP. Next, the properties of Cu-MCP-amylase were determined. It had optimal pH 7.0 and optimal temperature 70 degrees C with improved thermal stability. Finally, Cu-MCP-amylase showed significant catalytic capacity and stability in a column reactor, which could retain 80% of initial catalytic capacity after 40 recycle times. (C) 2013 Elsevier B.V. All rights reserved.