Enhancement of hyphal branching, aerial mycelium development and oidia formation induced by CaCO3 supplementation in liquid culture of Hypsizygus marmoreus

Abstract

The development of hyphae and sporulation of Hypsizygus marmoreus is strongly influenced by carbon dioxide (CO2) concentration. However, the role of CO2 in promoting the growth of this fungus remains insufficiently characterized. In this study, the effects of various supplements on the growth of H. marmoreus were investigated. Among all treatments, supplementation with 0.1% CaCO3 was the most effective, maintaining a neutral pH of 7.62 throughout cultivation and increasing CO2 accumulation in the headspace to 2,100 ppm compared to 1,700 ppm in the control. CaCO3 treatment also yielded the highest mycelial biomass of 26.00 mg / flask, markedly higher than the control at 17.40 mg / flask. Morphological observations indicated that the greatest hyphal branching frequency was 62.60 branches per 100 µm, significantly higher than the control at 5.33 branches per 100 µm. Furthermore, oidia production reached 6.53 × 106 spores per Petri dish, compared to 1.43 × 106 spores in the control. By comparison, supplementation with 0.1% Na2CO3 moderately enhanced branching and sporulation without increasing CO2 levels, while 0.1% CaCl2 enhanced mycelial biomass without increasing branching or spore formation. These findings highlight the potential of CaCO3 supplementation to improve yield and quality in commercial production of this mushroom.