Production of β-Mannanase by Penicillium italicum Subjected to Different Growth Conditions
O. O. Olaniyi *
Department of Microbiology, Federal University of Technology, P.M.B. 704, Akure, Nigeria.
B. J. Akinyele
Department of Microbiology, Federal University of Technology, P.M.B. 704, Akure, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Aims: The process parameters affecting enzyme production were optimized to ascertain the best optimal conditions for β-mannanase production by Penicillium italicum in solid state fermentation.
Study Design: Four stages of experimental processes were designed for this study. The first experiment, samples were withdrawn after 24, 48, 72, 96, 120, 144,168 and 192 h incubation. In second experiment, the fermentation media were incubated at different temperatures. In third experiment, the effect of different pH values on β-mannanase production was evaluated, while the fourth experiment described the supplementation of surfactants in mineral salt solution for β-mannanase production.
Place and Duration of Study: Microbiology Research Laboratory, Federal University of Technology, Akure Nigeria between September 2011 and March 2012.
Methodology: β-mannanase production was conducted using Locust Bean Gum (LBG) as the sole carbon source; moisten with mineral salt solution, and enzyme activity determined by dinitrosalicylic acid method, while protein content was determined by Lowry method.
Results: Maximum enzyme activity (146.389 U/ml) was observed after 72 h of incubation. Different surfactants were supplemented in the basal medium, and Sodium Dodecyl Sulfate (SDS) was observed to give the highest β-mannanase activity of 53.335 U/ml. Initial pH of the culture medium was optimized and a pH of 6.0 was found to support maximum enzyme activity (173.241 U/mg protein). The optimum incubation temperature was achieved at 35°C.
Conclusion: The results obtained provide information on optimal process parameters that might improve the yield of β-mannanase by P. italicum for better fish feed formulation, especially in the larval stages of fish fingerlings when the enzyme system is not efficient.
Keywords: β-mannanase, solid state fermentation, agrowastes, optimization, Penicillium italicum.