Value Addition of Agricultural Wastes for Improved Production …
273
3.2.1 Endoglucanase and Exoglucanase Activities
In mono-culture cultivation, organosolvent pretreated cauliflower leaf exhibited
highest amount of endoglucanase activity (160 ± 2.87
d,e IU ml
−1 ) by A. niger
while maximum exoglucanase activity was achieved with organosolvent pretreated
cauliflower stalk by the same fungus (107.23 ± 0.36
b,c IU ml
−1 ). However, there is
hardly any report on the production of cellulases by C. intermedia and according to
our results C. intermedia exhibited significant endoglucanase (119.45 ± 0.63
c IU
ml
−1 ) and exoglucanase activities (102.12 ± 0.39
c,d IU ml
−1 ) while cultivated on
organosolvent pretreated cauliflower wastes. According to our results for pretreated
cauliflower stalk, co-cultivation of the three selected fungal strains resulted in an
increase in endoglucanase activity and produced a little less exoglucanase activity
than individual culture of A. niger. From these findings, it could be inferred that
presence of A. niger in any combination led to increase in the enzymatic activity.
Thus, the other fungal strains may be considered as ‘helper strain’ and A. niger as
the main enzyme-producing strain.
3.2.2 β-glucosidase
It was evident from Table 2 that the three fungi used in this study showed different
β-glucosidase profiles. C. intermedia exhibited the highest amount of β-glucosidase
activity (87.28 ± 0.78 IU ml
−1 ) with organosolvent pretreated cauliflower wastes
under submerged fermentation. We observed higher β-glucosidase activity with the
co-culture cultivation of organosolvent pretreated cauliflower wastes (115 ± 2.47
c IU
ml
−1 ) in comparison to the independent culture. Co-culture cultivations have yielded
maximum β-glucosidase activity which acts as the positive inducer for the release of
endoglucanase and exoglucanase in significant quantity (Kumar et al. 2016).
3.2.3 Xylanase Activity
Among mono-culture fermentation, highest extracellular xylanase activity of 146.67
± 0.743
c IU ml
−1 by A. niger was shown in organosolvent pretreated cauliflower
leaf. Biosynthesis of xylanase was regulated by the activation of gene transcription to
xylanase by the transcriptional activator XYR1. Co-culture cultivation of pretreated
cauliflower wastes had shown maximum amount of extracellular xylanase activity
of 164.67 ± 0.31
c IU ml
−1 and 158.67 ± 3.18
c IU ml
−1 for leaf and stalk, respectively, (Table 2). Co-culture manifestation held promise because it had potential in
exerting synergistic effects by cohabiting and degradation of plant polysaccharides
by secretion of enzyme mixture extracellularly (Dhillon et al. 2011; Hu et al. 2011).
273
3.2.1 Endoglucanase and Exoglucanase Activities
In mono-culture cultivation, organosolvent pretreated cauliflower leaf exhibited
highest amount of endoglucanase activity (160 ± 2.87
d,e IU ml
−1 ) by A. niger
while maximum exoglucanase activity was achieved with organosolvent pretreated
cauliflower stalk by the same fungus (107.23 ± 0.36
b,c IU ml
−1 ). However, there is
hardly any report on the production of cellulases by C. intermedia and according to
our results C. intermedia exhibited significant endoglucanase (119.45 ± 0.63
c IU
ml
−1 ) and exoglucanase activities (102.12 ± 0.39
c,d IU ml
−1 ) while cultivated on
organosolvent pretreated cauliflower wastes. According to our results for pretreated
cauliflower stalk, co-cultivation of the three selected fungal strains resulted in an
increase in endoglucanase activity and produced a little less exoglucanase activity
than individual culture of A. niger. From these findings, it could be inferred that
presence of A. niger in any combination led to increase in the enzymatic activity.
Thus, the other fungal strains may be considered as ‘helper strain’ and A. niger as
the main enzyme-producing strain.
3.2.2 β-glucosidase
It was evident from Table 2 that the three fungi used in this study showed different
β-glucosidase profiles. C. intermedia exhibited the highest amount of β-glucosidase
activity (87.28 ± 0.78 IU ml
−1 ) with organosolvent pretreated cauliflower wastes
under submerged fermentation. We observed higher β-glucosidase activity with the
co-culture cultivation of organosolvent pretreated cauliflower wastes (115 ± 2.47
c IU
ml
−1 ) in comparison to the independent culture. Co-culture cultivations have yielded
maximum β-glucosidase activity which acts as the positive inducer for the release of
endoglucanase and exoglucanase in significant quantity (Kumar et al. 2016).
3.2.3 Xylanase Activity
Among mono-culture fermentation, highest extracellular xylanase activity of 146.67
± 0.743
c IU ml
−1 by A. niger was shown in organosolvent pretreated cauliflower
leaf. Biosynthesis of xylanase was regulated by the activation of gene transcription to
xylanase by the transcriptional activator XYR1. Co-culture cultivation of pretreated
cauliflower wastes had shown maximum amount of extracellular xylanase activity
of 164.67 ± 0.31
c IU ml
−1 and 158.67 ± 3.18
c IU ml
−1 for leaf and stalk, respectively, (Table 2). Co-culture manifestation held promise because it had potential in
exerting synergistic effects by cohabiting and degradation of plant polysaccharides
by secretion of enzyme mixture extracellularly (Dhillon et al. 2011; Hu et al. 2011).