Solid-state fermentation of cereal grains and sunflower seed hulls by Grifola gargal and Grifola sordulenta

Abstract

Grifola gargalandGrifola sordulentaare edible and medicinal mushrooms from Andino-Patagonian forests. There is a need tofind an alternative source for these mushrooms other than gathering them due toincreasing pressure on their habitats. Thus, in order tofind an appropriate technological pathway to growthese mushrooms, solid-state fermentation (SSF) in different substrates was studied. Mycelia cultivationon grains exhibited the best results when using wheat grains at pH 5.3, 24C, in darkness. When usingsunflower seed hulls (SSH) the protein content of the growth medium increased significantly after 45days SSF and a good laccase activity was measured. Further mycelium growth optimization was achievedin the presence of 0.01 N H2SO4,20mg/g Mn(II) and 100mg/g Zn(II) inG. gargal(50% SSH and 30% milledSSH, 15% residual substrate ofPleurotus ostreatus, and 5% wheat bran) and in G. sordulenta(80% SSH, 15%residual substrate of P. ostreatusand 5% wheat bran). Present preliminary studies on basidiome production showed that cultivation conditions should require at least a sterile substrate, 10e12 % inoculationrate, cold shock for primordia induction, and control from air borne contamination.