3.2. Fungal Material and Fermentation

Hericium erinaceus strain STMA 06157B was isolated from the basidiome of a specimens that were collected by Benno Stadler in Germany, Rhenania-Palatinate Province, near Eppenbrunn on Fagus sylvatica in September of 2006. The culture and the corresponding specimen are deposited at the herbarium and culture collection of the DSMZ, Braunschweig, Germany. Hericium flagellum (deposited as “H. alpestre” strain CBS 103681 had been originally isolated by N. Hallenberg from a specimens collected from Abies in Romania and was purchased from Westerdijk Fungal Biodiversity Centre (Utrecht, The Netherlands).

A seed culture of H. erinaceus was prepared as follows: five mycelial plugs (0.5 × 0.5 cm²) were cut from well grown yeast-malt-glucose agar (YMG) plates and were inoculated in 2 × 100 mL ZM/2 medium [16]. Flasks were incubated on a rotary shaker for 168 h at 24 °C and 160 rpm. 4 × 40 mL of the first inoculum was added in 4 × 1000 mL sterile Erlenmeyer flasks with 400 mL working volume of ZM/2 medium and incubated at the same conditions. A 10 L batch bioreactor, containing ZM/2 medium, equipped with temperature control, pH controller, and agitation, was inoculated with 10% of the seed culture, fermented for 72 h at 24 °C and 150 rpm. Finally it served as a seed culture for a 70 L bioreactor (10% seed culture added, fermented for 192 h at 24 °C and 150 rpm).

Hericium flagellum was fermented in two different media, ZM/2 and SP [d(+) glucose monohydrate 30 g/L, soy peptone 6 g/L, KH₂PO₄ 2.5 g/L, MgSO₄ 0.5 g/L, yeast extract 1.5 g/L, CaCl₂·2H₂O 73.5 mg/L, pH 6.0; after autoclaving 1 mL/L trace element solution sterile filtrated-FeCl₃·6H₂O 80 mg/L, MnSO₄·H₂O 30 mg/L, ZnSO₄·H₂O 90 mg/L, EDTA 400 mg/L]. Fifteen 500 mL Erlenmeyer flasks containing 200 mL media were used for each media and later incubated on a rotary shaker for 97 days (ZM/2 medium) and 60 days (SP medium), respectively, at 24 °C and 160 rpm.