Starch conversion by amylases from Aureobasidium pullulans

Abstract

A color variant strain (NRRL Y-12974) of Aureobasidium pullulans produced a saccharifying α-amylase and two forms of glucoamylase extracellularly when grown on starch at 28°C for 4 days. A sugar syrup containing DP1 (degree of polymerization) and DP2 (3:1) was made from maltodextrin DE (dextrose equivalent) 10 (35%, w/w) at 55°C and pH 4.5 using the amylase preparation (40 U g-1 DS (dry substance). The syrup composition was highly dependent upon substrate concentration but nearly independent of enzyme dose. Glucose syrup containing 93% glucose was made from maltodextrin DE 10 (35%, w/w) at 65°C and pH 4.5 using the same enzyme preparation at 100 U g-1 DS. The enzyme preparation (100 U g-1 DS) produced 98-100% glucose from raw corn starch at pH 4.5 and 50°C. © 1993 Society for Industrial Microbiology.