Protoplast Fusion of β-Glucosidase-Producing Aspergillus niger Strains

Abstract

Protoplast fusion, induced by polyethylene glycol and Ca2+, was carried out between two auxotrophic strains of Aspergillus niger. The fusion frequency ranged from 6.2 × 10-2-9.1 × 10-2. After induced haploidization of a diploid, various segregants showing combinations of the parental genetic markers were isolated. Unlike diploids, haploid segregants exhibited greater variations in their morphology and β-glucosidase activities. One segregant showed a 2.5-fold increase in β-glucosidase activity over those of the parents. Thus, this method appears promising for creating new recombinant strains of A. niger with improved β-glucosidase activities. © 1992 The Humana Press Inc.