Strain-specific features of Pleurotus ostreatus growth in vitro and some of its biological activities.

BACKGROUND: The production of Pleurotus ostreatus mycelium as a promising object for use in food and other industries is hampered by a lack of information about the strain-specificity of this fungus mycelium growth and its acquisition of various biological activities. Therefore, this research aimed to investigate mycelial growth of different P. ostreatus strains on varies solid and liquid media as well as to evaluate strains antagonistic, antibacterial, antiradical scavenging activities, and total phenolic content. RESULTS: Potato Dextrose Agar medium was suitable for all strains except P. ostreatus strain 2460. The best growth rate of P. ostreatus 2462 strain on solid culture media was 15.0 ± 0.8 mm/day, and mycelia best growth on liquid culture media-36.5 ± 0.2 g/l. P. ostreatus strains 551 and 1685 were more susceptible to positive effect of plant growth regulators Ivin, Methyur and Kamethur. Using of nutrient media based on combination of natural waste (amaranth flour cake and wheat germ, wheat bran, broken vermicelli and crumbs) has been increased the yield of P. ostreatus strains mycelium by 2.2-2.9 times compared to the control. All used P. ostreatus strains displayed strong antagonistic activity in co-cultivation with Aspergillus niger, Candida albicans, Issatchenkia orientalis, Fusarium poae, Microdochium nivale in dual-culture assay. P. ostreatus 2462 EtOAc mycelial extract good inhibited growth of Escherichia coli (17.0 ± 0.9 mm) while P. ostreatus 2460 suppressed Staphylococcus aureus growth (21.5 ± 0.5 mm) by agar well diffusion method. The highest radical scavenging effect displayed both mycelial extracts (EtOH and EtOAc) of P. ostreatus 1685 (61 and 56%) by DPPH assay as well as high phenolic content (7.17 and 6.73 mg GAE/g) by the Folin-Ciocalteu's method. The maximal total phenol content (7.52 mg GAE/g) demonstrated of P. ostreatus 2461 EtOH extract. CONCLUSIONS: It is found that the growth, antibacterial, antiradical scavenging activity as well as total phenolic content were dependent on studied P. ostreatus strains in contrast to antagonistic activity. The proposed culture mediums of natural waste could be an alternative to commercial mediums for the production mycelial biomass of P. ostreatus strains.

Antioxidant and antimicrobial potentials of mycelial extracts of Hohenbuehelia myxotricha grown in different liquid culture media.

In addition to their nutritional properties, mushrooms have emerged as a health supplement because of their medicinal potential. Many studies have shown that mushrooms exhibit important biological activities. Here, the antioxidant and antimicrobial activities of Hohenbuehelia myxotricha (Lév.) Singer mycelia cultivated on Sabouraud dextrose broth (SDB) and glucose peptone yeast (GPY) medium were studied. The total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI) of ethanolic extracts of mycelia were measured using Rel Assay kits. The antioxidant and oxidant potentials of H. myxotricha mycelial extracts were determined for the first time in the present study. The highest TAS, TOS, and OSI values of H. myxotricha were 5.416 ± 0.150 mmol/l, 1.320 ± 0.156 µmol/l, and 0.024 ± 0.003, respectively. Ethanolic mycelial extracts of H. myxotricha showed antimicrobial activities at concentrations from 25 to 200 µg/ml against all the studied bacteria (Acinetobacter baumannii, Enterococcus faecalis, Escherichia coli, Staphylococcus aureus, methicillin-resistant S. aureus, and Pseudomonas aeruginosa ) and fungi (Candida albicans, C. glabrata, and Issatchenkia orientalis ) tested by the agar dilution method. The antifungal activity of the extract was more significant than its antibacterial activity. The antioxidant, oxidant, and antimicrobial potentials of H. myxotricha mycelia varied depending on the culture media used. GPY medium was more suitable for the synthesis of antibiotic compounds against E. coli, while SDB medium was more appropriate for producing metabolites with antioxidant and antifungal properties. Based on the results, ethanolic extract of H. myxotricha mycelia showed a significant pharmacological potential and could be used as a natural antioxidative and antimicrobial source for health benefit.

Antiviral activity of Basidiomycete mycelia against influenza type A (serotype H1N1) and herpes simplex virus type 2 in cell culture.

In this study, we investigated the in vitro antiviral activity of the mycelia of higher mushrooms against influenza virus type A (serotype H1N1) and herpes simplex virus type 2 (HSV-2), strain BH. All 10 investigated mushroom species inhibited the reproduction of influenza virus strain A/FM/1/47 (H1N1) in MDCK cells reducing the infectious titer by 2.0-6.0 lg ID50. Four species, Pleurotus ostreatus, Fomes fomentarius, Auriporia aurea, and Trametes versicolor, were also determined to be effective against HSV-2 strain BH in RK-13 cells, with similar levels of inhibition as for influenza. For some of the investigated mushroom species-Pleurotus eryngii, Lyophyllum shimeji, and Flammulina velutipes-this is the first report of an anti-influenza effect. This study also reports the first data on the medicinal properties of A. aurea, including anti-influenza and antiherpetic activities. T. versicolor 353 mycelium was found to have a high therapeutic index (324.67), and may be a promising material for the pharmaceutical industry as an anti-influenza and antiherpetic agent with low toxicity. Mycelia with antiviral activity were obtained in our investigation by bioconversion of agricultural wastes (amaranth flour after CO2 extraction), which would reduce the cost of the final product and solve some ecological problems.

Some macronutrient content in mycelia and culture broth of medicinal mushrooms cultivated on amaranth flour.

The content of proteins, lipids, and amino and fatty acids was investigated in mycelium and culture broth of medicinal mushrooms Cordyceps sinensis, Pleurotus ostreatus, and Schizophyllum commune. Seven essential amino acids were present in the proteins of all mushroom samples, with aspartic (6.34%-14.29%) and glutamic (15.12%-17.51%) acids predominating in culture mycelium and glutamic acid (16.3%-19.1%) in culture broth. Lipids in the mycelium of species C. sinensis, P. ostreatus, and Sch. Commune consisted of 10 fatty acids and 12 fatty acids in culture broth in our experiments. Major acids in culture mycelium and culture broth of fungi were linoleic (42.43%-67.41%), oleic (10.47%-32.54%), and palmitic (16.43%-20.33%). The proteins and lipids in culture broth of studied species contained a higher level of total non-essential amino acids and unsaturated fatty acids as compared to those in culture mycelium.