Singh et al.

Bacillus licheniformis. Hassan and Karim (2012) observed optimum incubation

time with the highest amylase activities for both substrates namely rice straw

and OPEFB fibres after 48 h and a further increase in incubation time led to a

significant reduction in enzyme activity. The decline in enzyme activity might

be due to denaturation of α-amylase as a result of interactions with compounds

in the fermentation medium (Ramesh and Losane, 1987). Another possible

reason is due to the presence of some inhibitors that might inhibit the enzyme

secretion. Raj and Hemashenpagam (2012) also reported 48 h of incubation for

the highest amylase enzyme production from wheat bran by using Bacillus sp.

under solid state fermentation. Sameh et al. (2013) reported four days incubation

for maximum amylase enzyme production by using Bacillus sp. from crude millet.

Nagrajan et al. (2010) also reported 40h of incubation for maximum amylase

enzyme production from wheat bran by using Bacillus sp. while decreased yield

was observed due to further increase of incubation time. In contrast to the present

study Kalairasi and Parvatham (2013), Babu and Satyanarayana (1995) and Anto

et al. (2006) have reported that 72 h incubation for good enzyme production with

Bacillus cereus MTCC 10202, Bacillus coagulans and Bacillus cereus. Baysal

et al. (2003) also reported 48 h as optimum incubation time for alpha amylase

production using Bacillus sbutilis. In most cases the optimum incubation period

for alpha amylase production under SSF using Bacillus sp. varied from 48 to 72

h depending on the environmental conditions (Sivramakrishnan et al., 2006). Rai

and Solanki (2014) and Tabassum et al. (2014) have also reported 72 h incubation

time for Bacillus amyloliquefaciens and Bacillus licheniformis which is in contrast

with the present study. Rameshkumar and Sivasudha (2011) have reported similar

result of maximum enzyme production after 48 h of incubation and decrease in

the enzyme yield on further increase in incubation time. El-Shishtawy et al. (2014)

have reported maximum amylase enzyme production after 24 h of incubation time

using Bacillus sp. grown on wheat bran. α- Amylase production by Bacillus sp. in

SSF showed that the organism colonized well on the solid substrate and exhibited

good growth after 24h at 37°C. Maximum enzyme production was achieved after

48 h incubation (Sodhi et al., 2005).

Optimization of Nutritional Parameters for α- amylase production using

Bacillus licheniformis under solid state fermentation

Effect of additional carbon sources on α- amylase production by Bacillus

licheniformis under SSF condition

Growth and enzyme production of any organism are greatly influenced by the

nutrient available in the growth medium. Alpha amylase is an inducible enzyme.

The carbon sources in the medium are found to exert a profound effect on the

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International Journal of Bioinformatics and Biological Sciences : v.2 n.3&4. Dec. 2014