Simultaneous lipase production and immobilization: morphology and physiology study of Penicillium simplicissimum in submerged and solid-state fermentation with polypropylene as an inert support.

The influence of different carbon sources (glucose (G), olive oil (O), and a combination of both (GO)) in the physiology (biomass and lipase production) and morphology (light and environmental and scanning electron microscopy) of the fungus Penicillium simplicissimum by applying submerged (SmF) and solid-state (SSF) fermentations was investigated. The cultivation was carried out using polypropylene as hydrophobic inert support in SmF and SSF to understand better the influence of a support for the fungus growth and also provides the immobilization of lipases during its production. Micrographs show different morphologies: in SSF, the fungus grows on and inside the inert support independent of the media; in SmF, the formation of high-density spherical pellets obtained in medium GO leads to the best productivity and specific product yield Y.Conidiation is observed mainly in SSF, a few in SmF with polypropylene as inert support and not in SmF, which may indicate a stress condition in SSF. Possibly, the morphology acquired by the fungus under stressful conditions may be the key to the higher biomass and lipase productivity at SSF. The developed process with simultaneous production and immobilization of lipase leads to a new promissory biocatalyst once it can be directly applied with no need for downstream processes.