Enhancing submerged fermentation of Antrodia camphorata by low-frequency alternating magnetic field

Abstract

This work aimed to investigate the impact of low-frequency (30–300 kHz) alternating magnetic field (LF-AMF) on enhancing submerged fermentation of Antrodia camphorata (A. camphorata), a basidiomycete fungus. This study assessed mycelial biomass, active metabolites, microstructure, cytomembrane fluidity, and molecular mechanism. Under optimal magnetic treatment conditions, the mycelial biomass and the yields of polysaccharides and triterpenoids increased by 15.88, 24.26, and 26.85% at laboratory level and 8.99, 20.81, and 29.91% at scale-up level, respectively, compared with the control. The microstructures displayed that the magnetically treated mycelium showed a rough, loose, and wrinkled surface morphology, a slightly thinner cell wall, and enlarged vesicle and mitochondrial volume compared with the control. The cytomembrane fluidity increased over the magnetic exposure time. Transcriptomic analysis revealed that LF-AMF treatment enhanced the mycelium growth of A. camphorata by significantly up-regulating gene expression related to amino acid metabolism and synthesis and cell growth. Additionally, unigenes involved in RNA transport and endocytosis were up-regulated in response to magnetic stimulation to promote the accumulation of the active metabolites. Industrial relevanceA. camphorata is a precious edible medicinal basidiomycete with various pharmaceutical activities and high commercial value. However, the wild fruiting bodies of A. camphorata are scarce and expensive due to the host specificity and slow growth rate in nature. Our findings indicated that LF-AMF-assisted-submerged fermentation could be considered an effective way to produce A. camphorata mycelia at laboratory and scale-up levels, achieving efficient, high-quality, and large-scale production of precious edible fungus.