Utilization of Lignocellulosic Residues (Corn-cob and Pawpaw Fibre) as Substrates for Production and Optimization of Cellulase from Penicillium sp.

Lignocellulosic residues are abundant in agricultural and forest industries in various countries where
they remain under exploited. They have useful potential in microbial systems in the secretion of
cellulases The present work investigated theutilization of lignocellulosic residues (corn-cob, CC and
pawpaw fibre, PF) as substrates for production and optimization of cellulase from Penicillium sp.A
total of nine fungal isolates were gotten from compost soil and were screened for cellulolytic activity
using Standard Methods. Cellulase activity was determined by the DNS method on Congo red agar
plate. Out of the nine isolates, Isolate CPF-1 was selected and identified as Penicillium sp. based on
its cultural and morphological characteristics. The influence of basic fermentation parameters on
enzyme production in solid state fermentation and the effects of some physicochemical parameters on
crude cellulase activity/stability were studied. The data obtained from the study revealed that the
optimal pH and temperature values for the production of crude cellulase by the Penicillium sp. were
pH 5 and 30°C, respectively; with maximum cellulase activity of 37.32 IU/mL. Optimum cellulase
productivity of 15.787 IU/mL was obtained with CC as the substrate while 2.141 IU/mL was obtained
with PF substrate after 1 h of fermentation. The cellulase produced was most stable at pH 5 and
temperature of 40°C. Fe2+ and Co2+ stimulated cellulase activity whereas the other ions inhibited the
enzyme activity. This study has revealed the potentials of corn-cob and pawpaw fibre as substrates
for cellulase production by Penicillium sp. through solid state fermentation (SSF); with corn-cob as the
most suitable substrate. Considering that these substrates are cost-effective and abundant as well
renewable, they present cheaper substrate alternatives for potential large-scale cellulase production
and reduction in environmental pollution problems.