In situ immobilized β-glucosidase from Aspergillus phoenicis QM 329

Kati Réczey, Ingrid Persson, Folke Tjerneld, Bärbel Hahn-Hägerdal

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Abstract

Aspergillus phoenicis QM 329 was found to grow in the shape of beads in shake flasks and in an air-lift fermentor. Initial culture pH, pH profile during cultivation, carbon source, inoculum size and fermentor configuration influenced the retainment of the β-glucosidase activty in the mycelium. Glucose and soluble starch produced beads with the highest activity and the best stability. Glucose-derived beads were more homogeneous in size and shape than the starch-derived beads. These beads kept their integrity for 10 d at 50° C. After 48 h hydrolysis of 50 g/l cellobiose 75% of the initial enzyme activity remained. The beads could be air-dried and alcohol-sterilized with only minor loss of activity. The size of the beads could be controlled by varying the size of the conidia inoculum. In an air-lift fermentor with a working volume of 1500 ml,900 ml beads with an average diameter of 2 mm (estimated to 37-45,000 beads) were produced in less than 3 d with glucose as carbon source. The beads held a β-glucosidase activity of 0.140 IU/bead determined with the pNP assay.

Original languageEnglish
Pages (from-to)205-210
Number of pages6
JournalBiotechnology Techniques
Volume3
Issue number3
DOIs
Publication statusPublished - Mar 1 1989

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ASJC Scopus subject areas

  • Biochemistry
  • Applied Microbiology and Biotechnology

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