T. aurantiacus on alkali-treated bagasse at 45
C assisted nearly 70 U/ml of CMCase
following 96 h of incubation. The temperature optima for growth filter paper activity
and β-glycosidases activity by T. Aurantiacus were recorded to be 45, 40 and 70
C,
respectively (Chin and Cole 1982).
11.11 Effect of Inoculum Size
The inoculum density is a decisive factor that commands and may either clips or
extends the early lag phase of microbial growth curve. Surplus nutrient and lower
inoculum ratio often leads to extravagant mycelia blooming and retarded enzyme
production (Sharma et al. 1996; Haq et al. 2003). An exceeded microbial input could
permit raised percentage moisture and ceasing in microbial cell synthesis and
biocatalyst release, whereas diminished inoculum size may insist a longer incubation
for bioprocessing to achieve the target metabolite of interest (Baysol et al. 2003).
In a study of Azzaz et al. (2012), 4% inoculum fulfilled cellulase production on
modified medium using Aspergillus niger. Similarly, Alam et al. (2005) brought into
light that the elated cellulase activity of 0.043 units was acquired when cell density
of 5% (v/w) of Trichoderma harzianum was used on fermented oil palm biomass. As
reported by Omojasola et al. (2008), the cellulase activity tends to shrink at microbial
cell density exceeding 6% and 8% for pineapple peel and pulp fermentation,
respectively, by Aspergillus niger. The decline in cellulase production with rise in
inoculum might be due to aggregation of cells which could have reduced sugar and
oxygen intake and enzyme release.
Aspergillus niger spores with 1 Â 10
8 were inoculated into flasks and were
incubated at 30
C on a rotary shaker at 180 rpm for 7 days. The organism produced
higher amount of cellulase with 2.478, 2.632 and 9.84 U/ml of FPase on wheat bran,
rice bran and mixture of rice bran and wheat bran, respectively, in liquid-state
fermentation (Praveen Kumar et al. 2015). As observed by Narasimha et al.
(2006), Aspergillus niger gave maximum cellulase production on Czapek-Dox
medium when inoculum size of 2.0 Â 10
6 spores was used. Similarly, Sun et al.
(2010) reported 2 Â 10
8 spores of Trichoderma sp./flask (500 mL) were suitable for
cellulase production. The optimal inoculum volume for maximum cellulase (FPase
0.344 IU/ml and CMCase 2.50 IU/ml) was 7% (v/v) containing 10
6 spores per ml
beyond the limit which results in declined enzyme production attributed by the
deprivation of nutrient supplements accessible for the rapid biomass and accelerated
microbial growth. Optimal inoculum density of 8% v/v (12.41 mg cells/ml) for
CMCase production by Humicola insoles was recorded by Riaz et al. (2014).
11.12 Effect of Incubation Time
The growth curve of microorganisms and the production of hydrolytic enzymes
occur simultaneously; the activity increases until optimum incubation time is
reached and later becomes steady or declines (Sachslehner et al. 1998). Distinct
308
S. Akula and N. Golla
C assisted nearly 70 U/ml of CMCase
following 96 h of incubation. The temperature optima for growth filter paper activity
and β-glycosidases activity by T. Aurantiacus were recorded to be 45, 40 and 70
C,
respectively (Chin and Cole 1982).
11.11 Effect of Inoculum Size
The inoculum density is a decisive factor that commands and may either clips or
extends the early lag phase of microbial growth curve. Surplus nutrient and lower
inoculum ratio often leads to extravagant mycelia blooming and retarded enzyme
production (Sharma et al. 1996; Haq et al. 2003). An exceeded microbial input could
permit raised percentage moisture and ceasing in microbial cell synthesis and
biocatalyst release, whereas diminished inoculum size may insist a longer incubation
for bioprocessing to achieve the target metabolite of interest (Baysol et al. 2003).
In a study of Azzaz et al. (2012), 4% inoculum fulfilled cellulase production on
modified medium using Aspergillus niger. Similarly, Alam et al. (2005) brought into
light that the elated cellulase activity of 0.043 units was acquired when cell density
of 5% (v/w) of Trichoderma harzianum was used on fermented oil palm biomass. As
reported by Omojasola et al. (2008), the cellulase activity tends to shrink at microbial
cell density exceeding 6% and 8% for pineapple peel and pulp fermentation,
respectively, by Aspergillus niger. The decline in cellulase production with rise in
inoculum might be due to aggregation of cells which could have reduced sugar and
oxygen intake and enzyme release.
Aspergillus niger spores with 1 Â 10
8 were inoculated into flasks and were
incubated at 30
C on a rotary shaker at 180 rpm for 7 days. The organism produced
higher amount of cellulase with 2.478, 2.632 and 9.84 U/ml of FPase on wheat bran,
rice bran and mixture of rice bran and wheat bran, respectively, in liquid-state
fermentation (Praveen Kumar et al. 2015). As observed by Narasimha et al.
(2006), Aspergillus niger gave maximum cellulase production on Czapek-Dox
medium when inoculum size of 2.0 Â 10
6 spores was used. Similarly, Sun et al.
(2010) reported 2 Â 10
8 spores of Trichoderma sp./flask (500 mL) were suitable for
cellulase production. The optimal inoculum volume for maximum cellulase (FPase
0.344 IU/ml and CMCase 2.50 IU/ml) was 7% (v/v) containing 10
6 spores per ml
beyond the limit which results in declined enzyme production attributed by the
deprivation of nutrient supplements accessible for the rapid biomass and accelerated
microbial growth. Optimal inoculum density of 8% v/v (12.41 mg cells/ml) for
CMCase production by Humicola insoles was recorded by Riaz et al. (2014).
11.12 Effect of Incubation Time
The growth curve of microorganisms and the production of hydrolytic enzymes
occur simultaneously; the activity increases until optimum incubation time is
reached and later becomes steady or declines (Sachslehner et al. 1998). Distinct
308
S. Akula and N. Golla