85
ProCess engineering of solid- state fermentation
growth. e consequences of these difficulties for bio reac tor perfor-
mance have been well explored.
Evaporative cooling has been incorporated for large- scale operation
of rotating drum bio reac tor (RDB). e mass transfer coefficient for
evaporation from the bran bed to the head space has been determined
by measuring outlet water vapor concentrations for a RDB contain-
ing wet wheat bran. Sangsurasak and Mitchell (1995) suggested that
evaporation can remove as much as 78% of the heat from the bed
during the time of peak heat generation, even when the bed is aerated
with saturated air. is is due to the increase of water vapor pressure at
increasing temperature. It results in large moisture losses ...