Utilizing agricultural wastes as substrates for lipase production by candida rugosa NCIM 3462 in solid-state fermentation: Response surface optimization of fermentation parameters

Purpose: Utilizing agricultural wastes for the production of industrially valuable enzymes like lipases in solid state fermentation holds a promising alternative for conventional processes due to the various obvious advantages, especially the cost-effectiveness of the process and sustainability. In this present work, the feasibility of exploiting various agricultural residues for lipase production was evaluated and optimization of the important parameters was done using statistical methods. Methods: Candida rugosa NCIM 3462 was used for the production of lipase in solid state fermentation. Agro industrial wastes such as sesame oil cake, groundnut oil cake and coconut oil cake were used for the solid state fermentation. The Energy dispersion spectrum of the solid substrates was used to study the elemental composition of oil cakes. The response surface methodology was employed to optimize the lipase production and to study the effect of temperature and substrate to moisture ratio. Results: The maximum lipase activity of 22.40 U/g substrate was obtained using sesame oil cake which was 1.8 times the maximum activity obtained during the initial screening of variables by 'one-factor-at-time' approach. The optimized temperature and substrate to moisture ratio were found to be 32.3 C and 1:3.23 g/ml respectively. Conclusions: A predictive model for the combined effects of the independent variables using response surface methodology and artificial neural network was proved to be excellent empirical model for lipase production by C. rugosa in solid state fermentation and aid in improving lipase fermentation utilizing agricultural residues as valuable substrates.