# Free radical inhibition and total phenolic content in Fomitopsis betulina mycelium extract under different cultivation conditions

## TL;DR

This study explores how different cultivation conditions affect the growth and antioxidant properties of Fomitopsis betulina, a fungus known for its bioactive compounds.

## Contribution

The study identifies optimal cultivation parameters for maximizing biomass, phenolic content, and antioxidant activity in Fomitopsis betulina.

## Key findings

- Methanol and 70% ethanol were most effective for phenolic extraction, yielding 20.54±0.11 and 19.39±0.14mg GAE/g, respectively.
- Cultivation at 25°C and pH 6.0 maximized biomass growth, phenolic production, and antioxidant activity.

## Abstract

Given the growing recognition of Fomitopsis betulina for its bioactive potential, the influence of cultivation parameters on its mycelial development, metabolite production in submerged culture, and associated antioxidant activity remains insufficiently explored.

This study investigated the effects of various cultivation parameters on biomass accumulation, total phenolic content (TPC), and free radical scavenging activity, assessed using the Folin–Ciocalteu and DPPH assays respectively.

Among solvents tested, methanol and 70% ethanol were most effective for phenolic extraction, yielding 20.54±0.11 and 19.39±0.14mg GAE/g, respectively, while some solvents demonstrated strong DPPH inhibition (≥90%). A cultivation at 25°C supported optimal biomass accumulation (5.23±0.10g/L), phenolic compound total yield (101.10mg GAE/L), and antioxidant activity (91.66±0.40%). Static cultivation conditions promoted surface mycelial growth and resulted in the highest biomass yield (5.28±0.15g/L), strong DPPH inhibition (≥90%), and phenolic synthesis (101.75mg GAE/L). Among carbon sources, maltose favored biomass formation, whereas xylose led to the highest DPPH inhibition (89.68±0.91%) and TPC (16.08±0.06mg GAE/g; total yield: 15.92mg GAE/L). Of the nitrogen sources evaluated, ammonium sulfate supported the greatest biomass accumulation (2.64±0.21g/L), while ammonium nitrate enhanced antioxidant activity (80.54±3.10%). Although urea produced the highest TPC per gram of dry biomass (11.32±0.05mg GAE/g), ammonium sulfate resulted in the highest phenolic total yield (18.43mg GAE/L). An initial medium pH of 6.0 was identified as optimal for maximizing biomass growth, phenolic compound production, and antioxidant capacity. The cultivation parameters were ranked in order of influence as: temperature > duration of static cultivation > pH > duration of agitation > carbon source > nitrogen source. These findings provide a foundation for the targeted optimization of cultivation conditions to enhance biomass production, phenolic compound accumulation, and antioxidant activity in F. betulina (GenBank accession: PQ184655). The results contribute to the broader understanding of fungal secondary metabolite production and support future applications in biotechnology and functional food development. .