Effect of alkali treatment (NaOH) of eucalyptus leaves for hypercellulase production by Bacillus subtilis through submerge fermentation
Effect of alkali treatment (NaOH) of eucalyptus leaves for hypercellulase production by Bacillus subtilis through submerge fermentation
Sidra Iqbal1, Muhammad Irfan2*, Hafiz Abdullah Shakir1, Fouzia Tabbsum1, Javed Iqbal Qazi1
ABSTRACT
Eucalyptus leaves were pretreated through Box-Bhenken design of response surface methodology using three variables with three levels such as NaOH concentration (0.6, 0.8, 1.0%), substrate concentration (5, 10, 15%) and residence time (4, 6, 8h) with and without steam (autoclaving at 121oC for 15min and 15psi). After pretreatment, cellulase production was conducted in 250ml Erlenmeyer flask at 50 ºC, pH 5 with shaking speed of 120 rpm using 2% pretreated eucalyptus leaves as carbon source and 2% v/v inoculum size in submerged fermentation for 24h. Results showed that among these two treatments, only chemical treated substrates gave better enzyme yield as compared to chemical followed by steam. The highest FPase (2.526 IU/ml/min) activity was found at pretreatment conditions of 0.6% NaOH conc., 10% biomass loading and 4h reaction time while CMCase (2.803 IU/ml/min) at 1% NaOH conc., 15% biomass loading and 6h of reaction time. The proposed model was found highly significant as revealed by their F-values, P-values and R2 values. Results suggest the efficiency of Bacillus subtilis K-18 for cellulase production from eucalyptus leaves and it would be fruitful for future industrial exploitation in all perspectives.
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June 2017
Vol. 32, Iss. 1, Pages 1-158
