Effect of different substrates on bioactive compounds of Shiitake Mushroom

Abstract

Lentinula edodes (Shiitake mushroom) is a well-known culinary and medicinal fungus that is prized for its nutritional content and healing properties. This study examined the influence of four substrates—wheat straw, poplar, sheesham (Dalbergia sissoo), and mixed sawdust (1:1 mixture of poplar and sheesham sawdust)—on the antibacterial and antioxidant characteristics of Shiitake mushrooms. Fruiting bodies from each treatment were desiccated, pulverized, and extracted using ethyl acetate. Extracts were subjected to phytochemical analysis, antimicrobial testing against Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae, as well as antioxidant assays. The agar well diffusion method showed that mushrooms grown on mixed sawdust exhibited the highest antimicrobial activity against E. coli (12.00 ± 1.00 mm), P. aeruginosa (9.67 ± 0.52 mm), and K. pneumoniae (14.33 ± 1.07 mm). followed by poplar and wheat straw and sheesham substrate had the least activity. Mixed sawdust extracts also showed the lowest minimum inhibitory concentration (MIC) values of 100 μg/ml against E. coli and K. pneumoniae and 125 μg/ml against P. aeruginosa. The mixed sawdust extracts demonstrated superior antioxidant potential, indicated by the lowest IC₅₀ values in the DPPH (27.32 μg/ml) and β- carotene/linoleic acid (28.43 μg/ml) assays. Additionally, mushrooms grown on mixed sawdust showed the highest total phenolic content (34.77 mg GAE/gdw) and total flavonoid content (11.58 mg QE/gdw), which correlated positively with improved antibacterial and antioxidant activities.The study reveals that substrate composition greatly influences Shiitake mushroom bioactivity, with mixed sawdust being most effective, underscoring its potential for medicinal and nutraceutical applications.