Open AccessUpgrading brewer's spent grains by treatment with Aspergillus species
Author(s) -
Argyro Bekatorou,
Yiannis Bountas,
İbrahim M. Banat,
Maria Kanellakl
Publication year - 2007
Publication title -
chemical industry and chemical engineering quarterly
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.189
H-Index - 26
eISSN - 2217-7434
pISSN - 1451-9372
DOI - 10.2298/ciceq0702072b
Subject(s) - aspergillus awamori , aspergillus oryzae , food science , starch , chemistry , hydrolysis , biomass (ecology) , yeast , spore , sugar , yeast extract , fermentation , amylase , single cell protein , orange (colour) , botany , enzyme , biology , agronomy , biochemistry
Hydrolysis of brewer's spent grains (BSG) starch was examined using Aspergillus oryzae and A. awamori, at various conditions (pH, spore concentrations). Both fungi performed well, although A. oryzae proved more efficient in terms of process times and enzyme stability. BSG slurries were either treated directly with spore suspensions at 30?C, or with crude enzyme solutions at 45?C. In the first case, simultaneous biomass production and starch hydrolysis occurred, but in the second, transformation of sugars to biomass was avoided. In both cases, fermentable sugar production was not efficient (0.24-0.95 g/l and 0.47-1.83 g/l respectively) to support the use of the BSG hydrolyzates (BSGHs) as substrates e.g. for yeast propagation within the brewery. Alternatively, BSG treated directly with fungi could be proposed as protein enriched animal feeds. BSGHs were also evaluated as nutritious supplements in yeast growth media containing mixtures of molasses and orange pulp (as carbon sources), resulting in significantly improved biomass yields.