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Amylase production in solid state fermentation 61
Figure 7. Effect of different metal salts on amylase production (Error bars represent the SD among
replicates).
Effect of different concentration of NaCl on
amylase production in SSF
In this experiment, different concentrations of NaCl
(0.25-2.0 %) were employed to check the effect of
different concentration of NaCl on amylase
production by A.niger-ML-17 and R.oligosporus-
ML-<strong>10</strong>. Results indicated (Fig. 8) that A.niger-ML-
17 showed maximum (3.6 ±0.17 IU) enzyme
production at 0.5% concentration of NaCl in the
medium while R.oligosporus-ML-<strong>10</strong> gave
maximum titer of amylase (2.5± 0.13 IU) at 0.75%
concentration of NaCl. By increasing the NaCl
concentration beyond this decline in enzyme
production was observed. Kokab et al., (2003)
produced amylase from Bacillus subtilis in solid
state fermentation having medium containing 1.5%
concentration of NaCl. Patel et al., (2005) purified
and characterized the amylase enzyme from
A.oryzae in SSF having medium with 0.1%
concentration of NaCl.
Figure 8. Effect of different concentrations of NaCl on amylase production (Error bars represent the SD
among replicates).
Effect of surfactants on amylase production
Figure 9 illustrated the effect of different
surfactants on amylase production by A.niger –ML-
17 and R.oligosporus-ML-<strong>10</strong>. Result showed that
addition of Tween 80 (0.05 v/w) to the medium is
effective in enzyme production by both A.niger-
ML-17 (3.7 IU) and R.oligosporus-ML-<strong>10</strong> (2.5 IU)
in SSF. SDS and SLS had no strong influence on
enzyme production in solid state fermentation by
tested fungi. Negi and Banerjee (20<strong>10</strong>) reported
that Triton-X-<strong>10</strong>0 and sodium laurate sulphate are
the stimulator for enzyme production but sodium
laurate sulphate increased amylase production by
1.28 folds. Gupta et al. (2008) also reported that
different surfactants like Tween-80, Triton X-<strong>10</strong>0
and SDS had strong influence on amylase
production in submerged fermentation using
Aspergillus niger. Vu et al. (2011) stated that use of
Tween-80 as a surfactant effectively enhances the
cellulose production in solid state fermentation.
Production of hydrolytic enzymes can be enhanced
by the surfactants and fatty acids (Singh et al.,
1991). When surfactants are added, they enhance
the microbial growth in SSF by promoting the
penetration of water into the solid substrate matrix,
leading in an increase of surface area (Asgher et al.,
2006).