as the capital cost of the main SmF facility. Therefore, the use of wet SSF solids as
catalysts is a very efficient way to reduce downstream expenses.
11.7.2 The Use of Dry SSF Products as Environmental
Catalysts
Cammarota et al. (2001) found that dry SSF solids produced as fermented cakes of
babassu (Orbignya oleifera) by Penicillium restrictum improved the anaerobic
digestion of dairy waste waters by UASB (Up-flow Anaerobic Sludge Blanket)
reactors fed with organic loads having nearly 1 g L
-1 of fat. Untreated effluent had
a Chemical Oxygen Demand (COD) removal of only 50 % but pre-treated effluents had 90 % COD removal. Same procedure was applied successfully for the
anaerobic treatment of poultry slaughterhouse effluents (Valladão et al. 2007),
waste waters from swine meat (Rigo et al. 2008) and waste waters from dairy
industries (Damasceno et al. 2008). This use of SSF solids was also useful for the
pre-treatment of oily effluents digested by active sludge systems (Jung et al. 2002;
Rosa et al. 2006).
Those are examples of how dry SSF solids can be used as catalysts to solve
environmental problems. Again, downstream costs are lower than recovering
enzymes from SmF beers because the final moisture content is lower than 50 %
and the use of industrial oven dryers is straightforward.
11.7.3 The Use of SSF Solids as Industrial Biocatalysts
Nagy et al. (2006) found that dry SSF cultures of Mucor hiemalis, ‘‘without special
enzyme isolation processes’’ were able to resolve enantiomeric mixtures of
secondary alcohols. Fernandes et al. (2007) and Salum et al. (2010) have proven
the concept of using SSF dry solids as biocatalysts in the production of biodiesel
with ethanol instead of the conventional use of methanol and without a strong base
dissolved in water. Martínez-Ruiz et al. (2008) have used as biocatalyst the
cultures of Rhizopus sp. grown on perlite particles mixed with olive oil. This
biocatalyst was able to produce ethyl-oleate from a mixture of oleic acid, ethanol
and hexane. In this case, oil cakes will be used as solid substrates for the production of lipases, oils will be transformed in biodiesel and the final solid residues
can be recycled as feedstuffs or compost.
Hoskins and Lyons (2009) have used dry SSF solids obtained from cultures of
A. oryzae grown on distillery grains, as an enzyme complex to be mixed with the
corn mash in a similar way that Underkofler et al. (1947) used moldy bran but now
in the context of biofuel production. Also, Hölker (2007) has patented the production SSF catalysts by a continuous fermentor. He mixed such catalyst with
grass silage to improve biofuel production (methane or ethanol) by a subsequent
334
G. Viniegra-González
catalysts is a very efficient way to reduce downstream expenses.
11.7.2 The Use of Dry SSF Products as Environmental
Catalysts
Cammarota et al. (2001) found that dry SSF solids produced as fermented cakes of
babassu (Orbignya oleifera) by Penicillium restrictum improved the anaerobic
digestion of dairy waste waters by UASB (Up-flow Anaerobic Sludge Blanket)
reactors fed with organic loads having nearly 1 g L
-1 of fat. Untreated effluent had
a Chemical Oxygen Demand (COD) removal of only 50 % but pre-treated effluents had 90 % COD removal. Same procedure was applied successfully for the
anaerobic treatment of poultry slaughterhouse effluents (Valladão et al. 2007),
waste waters from swine meat (Rigo et al. 2008) and waste waters from dairy
industries (Damasceno et al. 2008). This use of SSF solids was also useful for the
pre-treatment of oily effluents digested by active sludge systems (Jung et al. 2002;
Rosa et al. 2006).
Those are examples of how dry SSF solids can be used as catalysts to solve
environmental problems. Again, downstream costs are lower than recovering
enzymes from SmF beers because the final moisture content is lower than 50 %
and the use of industrial oven dryers is straightforward.
11.7.3 The Use of SSF Solids as Industrial Biocatalysts
Nagy et al. (2006) found that dry SSF cultures of Mucor hiemalis, ‘‘without special
enzyme isolation processes’’ were able to resolve enantiomeric mixtures of
secondary alcohols. Fernandes et al. (2007) and Salum et al. (2010) have proven
the concept of using SSF dry solids as biocatalysts in the production of biodiesel
with ethanol instead of the conventional use of methanol and without a strong base
dissolved in water. Martínez-Ruiz et al. (2008) have used as biocatalyst the
cultures of Rhizopus sp. grown on perlite particles mixed with olive oil. This
biocatalyst was able to produce ethyl-oleate from a mixture of oleic acid, ethanol
and hexane. In this case, oil cakes will be used as solid substrates for the production of lipases, oils will be transformed in biodiesel and the final solid residues
can be recycled as feedstuffs or compost.
Hoskins and Lyons (2009) have used dry SSF solids obtained from cultures of
A. oryzae grown on distillery grains, as an enzyme complex to be mixed with the
corn mash in a similar way that Underkofler et al. (1947) used moldy bran but now
in the context of biofuel production. Also, Hölker (2007) has patented the production SSF catalysts by a continuous fermentor. He mixed such catalyst with
grass silage to improve biofuel production (methane or ethanol) by a subsequent
334
G. Viniegra-González