Characteristics of yeast invertase immobilized on porous cellulose beads

✍ Scribed by Paul A. Dickensheets; Li Fu Chen; George T. Tsao

• Publisher: John Wiley and Sons
• Year: 1977
• Tongue: English
• Weight: 348 KB
• Volume: 19
• Category: Article
• ISSN: 0006-3592
• DOI: 10.1002/bit.260190307

✦ Synopsis

Abstract

Invertase from Candida utilis was immobilized on porous cellulose beads by an ionic‐quanidino bond. The immobilized invertase showed optimum activity between pH 4.0 and 5.4, while the free enzyme had a sharp optimum at pH 4.1. Both temperature profiles were fairly similar up to 55°C. However, above this temperature the immobilized enzyme was more stable than the free enzyme. From the temperature data, the activation energies were found to be 7,322 and 4,052 cal/g mol for the free and the immobilized enzyme, respectively.

Candida invertase shows characteristics of substrate inhibition. Both the K~m~ and K~i~ for the free and the immobilized enzymes were determined. The apparent K~i~ for the immobilized invertase was much higher than the K~i~ of the free enzyme, suggesting a diffusion effect. Immobilized invertase molecules deep in the pores only see sucrose concentrations much less than the bulk concentrations. Immobilization, thus, offers certain processing advantages in this regard.