Production and Optimization of cellulase enzyme under Submerged and Solid State Fermentation from Trichoderma Isolates
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Date
2011-10
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Addis Ababa University
Abstract
Pure cellulose and agricultural wastes were used as sole carbon sources for the production of
cellulase enzymes by Trichoderma isolates in both SmF and SSF, respectively. These isolates
(seven) were obtained from Mycology laboratory, Faculty of Life science, Addis Ababa
University. Carboxymethyl cellulose (CMC) and Congo red were used to screen four isolates
for their ability to produce cellulase enzymes. Cellulase production was assayed by
measuring the amount of glucose released in μmol/ml/min by using the DNS assay method at
540nm. To maximize the cellulase production, the critical parameters like carbon source,
nitrogen source, cellulose concentration, temperature and pH were optimized under SmF. The
highest cellulase enzyme activity was observed after 12 days of incubation on media
containing, yeast extract (1%), cellulose concentration (1%) and pH (5.5) from all isolates
under SmF whereas under SSF maximum cellulase enzyme was recorded between 5-11 days
incubation. WB, RB and WS were found to suitable for high cellulase production whereas CS,
CP and BB relatively showed the least cellulase production in SSF. Trichoderma isolates
AUT1 produce the highest CMCase on WS (5.68U/g), AUT5 on rice bran (8.15U/g), AUT2
and AUT4 on wheat bran, their enzymatic activities were 4.92U/g and 7.01U/g, respectively.
Enzyme synthesis was repressed in the presence of glucose and fructose while it was induced
in the presence of maltose and lactose in SmF. The maximum amount of cellulase was
observed between 55% to 65% moisture contents. It is evident from the present study, solid
state fermentation was better than liquid state fermentation for the production of cellulase by
Trichoderma isolates using agricultural wastes. The cellulase enzymes produced by
Trichoderma isolates were active at temperature ranges of 40-60oC and pH values 4.5-6.5.
Key words:- Agricultural wastes, Carboxymethyl cellulase, Cellulase activity, DNS methods
and Congo red
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Keywords
Agricultural wastes, Carboxymethyl cellulase, Cellulase activity, DNS methods and Congo red