Aspergillus niger I-1472 and Pycnoporus cinnabarinus MUCL39533, selected for the biotransformation of ferulic acid to vanillin, are also able to produce cell wall polysaccharide-degrading enzymes and feruloyl esterases

The filamentous fungal strains Aspergillus niger I-1472 and Pycnoporus cinn abarinus MUCL39533, previously selected for the bioconversion of ferulic ac id to vanillic acid and vanillin respectively, were grown on sugar beet pul p. A large spectrum of polysaccharide-degrading enzymes was produced by A. niger and very few levels of feruloyl esterases were found. In contrast, P, cinnabarinus culture filtrate contained low amount of polysaccharide-degra ding enzymes and no feruloyl esterases. In order to enhance feruloyl estera ses in A. niger cultures, feruloylated oligosaccharide-rich fractions were prepared from sugar beet pulp or cereal bran and used as carbon sources. Nu mber of polysaccharide-degrading enzymes were induced. Feruloyl esterases w ere much higher in maize bran-based medium than in sugar beet pulp-based me dium, demonstrating the ability of carbon sources originating from maize to induce the synthesis of feruloyl esterases. Thus, A. niger I-1472 could be interesting to release ferulic acid from sugar beet pulp or maize bran. (C ) 2001 Elsevier Science Inc. AU rights reserved.