Inoculum strategies for Penicillium simplicissimum lipase production by solid-state fermentation using a residue from the babassu oil industry

Two alternative inoculation strategies for lipase production by the fungus Penicillium simplicissimum were tested in solid-state fermentation using a residue from the babassu oil industry (babassu cake),. Conventional spore inoculation was compared with fungal pellets grown in liquid medium and with inocula consisting of fermented cake. Fungal pellets delayed lipase production whereas fermented cake accelerated enzyme synthesis, yielding a productivity of 0.45 U g(-1) h(-1), which is equivalent to the highest values obtained with conventional inocula. Therefore, a 2(2) factorial design was used to determine the best conditions for lipase production with fermented cake as inoculum strategy, varying the inoculum propagation time and inoculum concentration. Lipase activity and productivity reached 30 U g-1 and 0.63 U g(-1) h(-1), respectively, with 10% inoculum and 36 h. Thus, fermented cake inocula increased production 1.5-fold with 10 times fewer spores than in conventional inoculation, indicating that fermented solids are an interesting alternative for inoculum development in solid-state fermentation, mainly for large-scale processes. (c) 2007 Society of Chemical Industry