Spouted Bed Drying as a Method for Enzyme Immobilization

Abstract

Usually immobilization is a requirement for the use of enzymes as an industrial biocatalyst. In this work, endophytic fungus Cercospora kikuchii lipase was immobilized by covalent binding on agricultural by-products and microcrystalline cellulose. The enzyme support system was submitted to spouted bed drying. Lipase immobilized on microcrystalline cellulose with 1.5% of glutaraldehyde showed the best results, presenting 179.1% of the original activity after drying, followed by rice husk (173.9%), corn stover (169.8%), sugarcane bagasse (157.3%), green coconut fiber (102.3%), and corncob (99.8%). The immobilized derivatives obtained showed a decreased enzyme activity with an average of only 17.31%, whereas the enzyme in its free form lost 85.8% of its initial activity after storage for 6 months. The operational stability showed that the biocatalysts prepared retained an average of 67.2% of the initial activity after five reuse cycles. The results showed that the use of agricultural by-products as low-cost support material associated with the spouted bed drying is promising and can contribute to industrial application of biocatalysts.

Keywords:

• Agricultural by-products
• Cercospora kikuchii
• Enzyme immobilization
• Enzyme stabilization
• Lipase
• Spouted bed

ACKNOWLEDGMENTS

This study was supported by the State of São Paulo Research Foundation (FAPESP). T.A. Costa-Silva received a fellowship from FAPESP (Grant # 2011/00743-8).

Notes

^a The responses were calculated from triplicate runs.