High Production of Cellulase by a Newly Isolated Strain Paenibacillus sp. IM7

Abstract

With increasing fossil fuel price and environmental concern, alternative and renewable resources have become attractive. However, a large amount of the cheapest or negative-cost lignocellulosic biomass produced from agriculture and forest-based industries is the most abundant renewable resource to convert biofuels and value-added chemicals. The aim of this study was to produce carboxymethyl cellulase (CMCase), a key enzyme for utilizing lignocellulosic biomass produced in agriculture and forest-based industries to produce biofuels and value-added bioproduct. Five potential bacterial strains isolated from soil and rotted wood samples from Kingfisher Lake, Thunder Bay, Canada were screened for their cellulolytic activity using carboxymethyl cellulose as the sole carbon source. The most promising strain IM7 was identified as Paenibacillus sp. on the basis of 16S rRNA gene sequence analysis. In this study, the optimal conditions for high production of CMCase were defined in a completely aerobic process. The newly isolated Paenibacillus sp. IM7 strain showed the highest CMCase activity up to 17.7 ± 0.17 IU/mL using 1.5% yeast extract in the culture medium as a nitrogen source. Moreover, when the culture medium supplemented with 2% mannose as an inducer the CMCase activity was markedly boosted up to 24.59 ± 0.09 IU/mL. The optimum pH and temperature of the culture for CMCase production by the strain IM7 were 5.0 and 30 °C respectively, and the significant enzyme production was obtained at a wide temperature range of 25–55 °C. Therefore, this Paenibacillus IM7 strain could be a potential candidate for CMCase production in an industrial bioconversion process.