Six species of white-rot fungi (Agrocybe aegerita SMR 206, Pleurotus ostreatus SMR 684, Trametes versicolor SMR 117, Pleurotus columbinus SMR 688, Pleurotus eryngii SMR 151 and Panus tigrinus SMR 707) were screened for growth ability on two digestates obtained from anaerobic digestion at commercial scale of corn silage (CSD) and of a mixture of substrates (cow manure, 50%; grass silage, 10%; milk whey, 21%; poultry litter, 10%; sugar beet-molasses, 9%) (MSD). Pure fungal species cultures were grown in sterilized Petri dishes containing 3% malt extract and 1.5% agar. When the mycelium reached an abundant biomass, discs of 9 mm were cut and used for inoculation of the digestate. Each circle was placed in the centre of Petri dishes (11 cm diameter) containing 15 g of different substrates, namely: wheat straw (WS) 100% (control); WS 50% + CSD 50%; WS 50% + MSD 50%; CSD 100%; MSD 100%. Moisture was fixed at 70% in each substrate. Fungal growth was evaluated by measuring the diameter of the area covered by the mycelium for 19 days. Among the tested strains, P. tigrinus showed the fastest growth on the control medium, reaching the full colonization (11 cm) in 7 days, followed by T. versicolor and P. ostreatus (11 cm in 9 days). The latter two strains also exhibited a similar trend of growth on WS 50% + CSD 50% and on CSD 100%, reaching the maximum proliferation on such media in the shortest time (8 and 11 days, respectively). MSD was the harder substrate to colonize for all the tested fungi. In particular, the maximum growth on WS 50% + MSD 50% was reached after 12 days by T. versicolor and P. ostreatus, and after about 17 days by the remaining strains. None of the six fungal species was able to fully colonize the medium composed by MSD 100% in 19 days. Our results show that the ability of a certain fungal strain to grow on a digestate can be severely influenced by the feedstock type used in the anaerobic digestion process. Among the tested fungi, P. ostreatus resulted to be one of the most suitable for cultivation on CSD and, due to its economical relevance, it might represent a valuable resource for biorefinery activity on anaerobic digestates with the aim of: i) producing edible mushrooms; ii) degrading lignin; iii) obtaining value-added products (such as chitin) from fungal biomass.
Screening of fungal species for their ability to colonize different anaerobic digestates
Guglielmo Santi;Alberto Battistelli;Valerio G Muzzini;Emanuela Galli
2014
Abstract
Six species of white-rot fungi (Agrocybe aegerita SMR 206, Pleurotus ostreatus SMR 684, Trametes versicolor SMR 117, Pleurotus columbinus SMR 688, Pleurotus eryngii SMR 151 and Panus tigrinus SMR 707) were screened for growth ability on two digestates obtained from anaerobic digestion at commercial scale of corn silage (CSD) and of a mixture of substrates (cow manure, 50%; grass silage, 10%; milk whey, 21%; poultry litter, 10%; sugar beet-molasses, 9%) (MSD). Pure fungal species cultures were grown in sterilized Petri dishes containing 3% malt extract and 1.5% agar. When the mycelium reached an abundant biomass, discs of 9 mm were cut and used for inoculation of the digestate. Each circle was placed in the centre of Petri dishes (11 cm diameter) containing 15 g of different substrates, namely: wheat straw (WS) 100% (control); WS 50% + CSD 50%; WS 50% + MSD 50%; CSD 100%; MSD 100%. Moisture was fixed at 70% in each substrate. Fungal growth was evaluated by measuring the diameter of the area covered by the mycelium for 19 days. Among the tested strains, P. tigrinus showed the fastest growth on the control medium, reaching the full colonization (11 cm) in 7 days, followed by T. versicolor and P. ostreatus (11 cm in 9 days). The latter two strains also exhibited a similar trend of growth on WS 50% + CSD 50% and on CSD 100%, reaching the maximum proliferation on such media in the shortest time (8 and 11 days, respectively). MSD was the harder substrate to colonize for all the tested fungi. In particular, the maximum growth on WS 50% + MSD 50% was reached after 12 days by T. versicolor and P. ostreatus, and after about 17 days by the remaining strains. None of the six fungal species was able to fully colonize the medium composed by MSD 100% in 19 days. Our results show that the ability of a certain fungal strain to grow on a digestate can be severely influenced by the feedstock type used in the anaerobic digestion process. Among the tested fungi, P. ostreatus resulted to be one of the most suitable for cultivation on CSD and, due to its economical relevance, it might represent a valuable resource for biorefinery activity on anaerobic digestates with the aim of: i) producing edible mushrooms; ii) degrading lignin; iii) obtaining value-added products (such as chitin) from fungal biomass.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
