AMYLASE PRODUCTION BY ASPERGILLUS ORYZAE IN SUBMERGED AND SOLID STATE FERMENTATIONS - Biochemical Engineering - page 196

Taking into account these observations, TAA production by A. oryzae FQB-01 under SSF
using sugar cane bagasse as a support material was optimized by determining the optimal
particle size, temperature, pH, inoculum size, initial moisture content and starch concentration
in the solid support.
The first optimization experiment was performed to determine the influence of different
sugar cane particle sizes (<1.0, 1.0-2.0, 2.0-5.0, 5.0-10.0 and 10.0-15.0 mm) on amylase
production by A. oryzae FQB-01 in SSF. The results obtained are shown in Figure 5.
Maximum enzyme production (191 EU/g of dry support) was observed when the particle size
of bagasse was in the range of 5.0-10.0 mm, decreasing for low of high particle sizes. Thus,
this particle size probably provides the most effective support material for attachment of the
fungal strain (Laxmi et al., 2008), or facilitates the mass transfer performance (gas and
nutrient diffusion) greatly. This provides better respiration/aeration efficiency (Pandey et al.,
1999; Balkan & Ertan, 2007) and an increased availability of nutrients (Mazutti et al., 2007).
These facts favour growth and enzyme production (Pandey et al., 1999; Balkan & Ertan,
2007). In subsequent experiments, therefore, a particle size between 5.0-10.0 mm was used
for the production of amylase by A. oryzae FQB-01.
After optimizing the particle size of bagasse, the following experiment was focused on
the determination of the optimal pH and incubation temperature for high amylase production.
Table 6 summarizes the response for each individual experiment along with the calculated
response and the significance analysis of the model terms. Table 7 shows the significance
analysis of the empirical model (2), which gives the level of TAA as a function of pH and
temperature. The value of the determination coefficient (0.940) suggested that the fitted
model could explain 94% of the total variation. Thus, it can be concluded that the quadratic
model was appropriate to fit satisfactorily the experimental data.
The TAA production could be therefore predicted by the model:

TAA (EU/gds) = 185.5 + 16.8 T + 32.9 pH -34.4 T 2 - 29.8 pH 2 (2)

Figure 5. Effect of particle size of the sugar cane bagasse on the production of total amylolytic activity
( TAA ) by A. oryzae FQB-01 in solid state fermentation.