11.2.1 Scale-up of SSF Trays Packed with Solid Particles
Packing density of solid particles is a function of the particle geometry. According
to Kyrylyuk and Philipse (2011), random packing of spheres yields a packing
fraction around 0.63 (37 % porosity) and a maximal random packing of rods of 0.7
(30 % porosity). These estimates are higher than the experimental result of 0.49
packing density of 51 % moist wheat bran particles (Underkofler et al. 1947) in
fermentation trays or 0.45 packing density for cylindrical columns packed with
Amberlite beads (Favela-Torres et al. 1998).
Underkofler et al. (1947) reported the commercial operation of a moldy bran
factory with a throughput daily capacity of 10 tons using mechanically loaded
trays, 125 kg each (dry basis). Fermentation beds were, 3.8 cm thick, 1.5 m (5 ft)
wide, and 4.3 m (14 ft) long. Hence, each daily batch involved the loading of 80
trays (10 trays h
-1 ). This shows that it is feasible to scale-up SSF tray factories if
the loading and unloading of trays is made mechanically. For that purpose, the use
of external mechanical vibrators has been patented (Virtanen et al. 2008).
Upgrades of the tray SSF process are currently operated by a proprietary design of
Altech, Co. implemented in Ciudad Serdán, Puebla (México) and by Plafractor
Ò
technology of Biocon in Bangalore, India (Mazumdar and Suryanarayan 1999).
11.3 A Brief Background of Enzyme Production by SSF
11.3.1 SSF in Koji-Based Processes
Production of enzymes by SSF is necessary for the production of Far East
fermented foods such as shoyu (soybean sauce), misó (mold fermented paste), natto
(Bacillus fermented soybeans), saké (rice wine), and vinegar (Hesseltine 1983). He
mentioned that in 1979, the volume of fermented grains (rice or soybeans) in Japan
and Korea was around 800,000 tons. They all require the production of a crude
enzyme preparation called koji made of rice-fermented mashes inoculated with
Aspergillus oryzae. processes used at industrial scale for more than a century in
Japan and China (Machida et al. 2008).
11.3.2 Adaptation of Koji Industry to Starch Industry in USA
Takamine (1894a) adapted the koji process, using wheat bran for the production
taka-koji or ‘‘moyashi’’ obtained by drying the spent moldy bran. He later patented
the making of an alcoholic precipitate of a water extract of taka-koji (Takamine
1894b) called ‘‘diastatic enzyme.’’ This precipitate was sold as a digestive aid
11 New Horizons for the Production of Industrial Enzymes
325
Packing density of solid particles is a function of the particle geometry. According
to Kyrylyuk and Philipse (2011), random packing of spheres yields a packing
fraction around 0.63 (37 % porosity) and a maximal random packing of rods of 0.7
(30 % porosity). These estimates are higher than the experimental result of 0.49
packing density of 51 % moist wheat bran particles (Underkofler et al. 1947) in
fermentation trays or 0.45 packing density for cylindrical columns packed with
Amberlite beads (Favela-Torres et al. 1998).
Underkofler et al. (1947) reported the commercial operation of a moldy bran
factory with a throughput daily capacity of 10 tons using mechanically loaded
trays, 125 kg each (dry basis). Fermentation beds were, 3.8 cm thick, 1.5 m (5 ft)
wide, and 4.3 m (14 ft) long. Hence, each daily batch involved the loading of 80
trays (10 trays h
-1 ). This shows that it is feasible to scale-up SSF tray factories if
the loading and unloading of trays is made mechanically. For that purpose, the use
of external mechanical vibrators has been patented (Virtanen et al. 2008).
Upgrades of the tray SSF process are currently operated by a proprietary design of
Altech, Co. implemented in Ciudad Serdán, Puebla (México) and by Plafractor
Ò
technology of Biocon in Bangalore, India (Mazumdar and Suryanarayan 1999).
11.3 A Brief Background of Enzyme Production by SSF
11.3.1 SSF in Koji-Based Processes
Production of enzymes by SSF is necessary for the production of Far East
fermented foods such as shoyu (soybean sauce), misó (mold fermented paste), natto
(Bacillus fermented soybeans), saké (rice wine), and vinegar (Hesseltine 1983). He
mentioned that in 1979, the volume of fermented grains (rice or soybeans) in Japan
and Korea was around 800,000 tons. They all require the production of a crude
enzyme preparation called koji made of rice-fermented mashes inoculated with
Aspergillus oryzae. processes used at industrial scale for more than a century in
Japan and China (Machida et al. 2008).
11.3.2 Adaptation of Koji Industry to Starch Industry in USA
Takamine (1894a) adapted the koji process, using wheat bran for the production
taka-koji or ‘‘moyashi’’ obtained by drying the spent moldy bran. He later patented
the making of an alcoholic precipitate of a water extract of taka-koji (Takamine
1894b) called ‘‘diastatic enzyme.’’ This precipitate was sold as a digestive aid
11 New Horizons for the Production of Industrial Enzymes
325