Biochemical analysis of cultivated mushroom, Pleurotus florida and synthesis of silver nanoparticles for enhanced antimicrobial effects on clinically important human pathogens

Abstract

The oyster mushroom (Pleurotus florida) is one of the most important edible and medicinal mushroom because it contains a variety of effective bioactive compounds. This study aims to produce a novel biomaterial to combat microbial infections without any harmful effects. Accordingly, an eco-friendly and non-toxic silver nanoparticles (AgNPs) was synthesized usingthe extract of oyster mushroom, P. florida. In this study, the dietary nutrient levels of the edible mushroom, P. floridawas analyzed and AgNPs was synthesized. The synergistic effects of myco-synthesized AgNPs extract have been projected as an alternative to traditional antibiotics owing to their superior antimicrobial properties. The authenticated mushroomP. floridawas cultivated within a total crop period of 41 ± 2 days with a total yield of 1450 ± 200 g/ bed. The nutritional profile ofP. floridadried mushroom exhibits a high amount of protein (42.98%), followed by carbohydrate (11.34%), moisture (7.88%), ash (7.19%), crude fibre (4.55%), and fat (1.98%). Flame photometer and atomic absorption spectroscopy (AAS) study reveals the presence of minerals in P. florida dried mushroom. The dried mushroom contains more of vitamin C (34.5 mg/ g) followed by vitamin A (24.6 mg/ g), vitamin B (Thiamine- 1.56 mg/ g, Riboflavin-3.35 mg/ g, and Niacin- 8.43 mg/ g) and vitamin E (4.34 mg/ g). The mycosynthesized AgNPs were characterized by various bio-physical techniques. A strong absorbance peak was found at 422 nm by UV–Vis spectroscopy. XRD reflected the pure crystalline form of AgNPs and the crystalline size was ∼ 12.62 nm. The presence of different functional groups in the reduction process was observed by FTIR. HRTEM and SAED revealed that the AgNPs were spherical, crystalline with smooth surface morphology and the mean particle size was 11 nm. The synthesized AgNPs with mushroom extract were exhibited significant antibacterial activity against Streptococcus pyogenes (22.17 ± 0.66 mm), Enterococcus faecalis (16.54 ± 0.88 mm), Klebsiella pneumoniae (26.32 ± 0.88 mm), Shigella flexneri (27.21 ± 0.66 mm), Candida albicans (15.13 ± 0.33 mm) and Aspergillus fumigatus (14.89 ± 0.33 mm). The bactericidal activity was found to increase significantly with increasing synergistic AgNPs with mushroom extract concentration. Among the tested ratios of AgNPs to mushroom extract, the ratios with increased concentration of AgNPs (4:1) showed better antimicrobial action. This work clearly indicated that synergistic antimicrobial effects of mushroom extract and mycosynthesized AgNPs can act as a very effective antimicrobial material in future to control various diseases caused by microbial infection.