Effect of Pseudomonas fluorescens and Bacillus cereus on the Biomass Production and Bioactivity of Lentinus tigrinus and Lentinus strigosus in Submerged Culture

Mushrooms have gained global recognition for their nutritional and therapeutic importance, as they are rich in bioactive metabolites that contribute to disease prevention and treatment. This study underlined the submerged cultivation utilizing Pseudomonas fluorescens BIOTECH 1123 and Bacillus cereus BIOTECH 1509 as biostimulants in the mycelial biomass production of Lentinus tigrinus and Lentinus strigosus. The antibacterial properties of the ethanolic extracts of L. tigrinus and L. strigosus were assessed using the disc diffusion technique, while their antioxidant potential was evaluated through the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. Both L. tigrinus and L. strigosus exhibited higher mycelial dry weights when cultured with P. fluorescens and B. cereus, compared to the control setup. All ethanolic extracts obtained from L. tigrinus and L. strigosus demonstrated antioxidant activity, indicating the presence of compounds with potential health benefits. Notably, the ethanolic extracts of L. tigrinus cultures co-inoculated with B. cereus on the same day as the fungal mycelia exhibited antibacterial activity against Staphylococcus aureus BIOTECH 1582, producing an inhibition zone of 15.60 mm. Similarly, extracts from L. strigosus that were inoculated with sterile distilled water on day 0 also showed antibacterial activity, producing a 6.54 mm inhibition zone against the same bacterial strain. Moreover, the ethanolic extract of L. strigosus showed an 8.11 mm zone of inhibition after 5 days of mycelial incubation prior to B. cereus introduction. In conclusion, co-cultivating L. tigrinus and L. strigosus with beneficial bacteria enhanced mycelial yield and produced extracts with notable antioxidant and antibacterial activities, supporting their potential in sustainable mushroom biotechnology and functional product development.