Cereal-based biorefinery development: Integrated enzyme production for cereal flour hydrolysis

Restructuring the traditional fermentation industry into viable biorefineries for the production of fuels, chemicals and plastics is essential in order to replace (petro)chemical processing. This work presents engineering aspects of Aspergillus awamori submerged fermentation for on-site production of an enzymatic consortium that contains glucoamylase, protease and phosphatase. The crude broth filtrate was used for the production of wheat flour hydrolysates. Improvements on traditional starch hydrolysis carried out in two stages (liquefaction and saccharification) were attempted through integration of unit operations and reduction of processing temperature and reaction duration. An initial increase of temperature to 68°C and a subsequent decrease to 60°C for the rest of the enzymatic hydrolysis resulted in a starch to glucose conversion yield of 94 and 92% when a wheat flour concentration and commercial starch concentration of 225 g L-1 was used, respectively. The use of crude broth filtrates resulted in the simultaneous hydrolysis of wheat protein and phytic acid, as was indicated by the increase in free amino nitrogen and phosphorus concentration, respectively. © 2006 Wiley Periodicals, Inc.