Morphology Engineering: Uniform <i>Ganoderma lucidum</i> Pellet Formation in Coconut Juice by Bidirectional Submerged Fermentation

Two different mycelia morphologies (clumps and pellets) of Ganoderma lucidum can be produced by bidirectional submerged fermentation (BSF) with coconut water. No mycelia growth was observed when coconut milk was used as the substrate. Ganoderma lucidum pellets contributed to higher yields of polysaccharides and triterpenes, as well as stronger antioxidant activity. This study investigated the regulation of key fermentation parameters on G. lucidum pellet formation. These parameters included inoculum size, aeration rate, substrate viscosity, and rotation speed. It also established prediction models for pellet number and size. With increasing inoculum size, aeration rate, and rotation speed, pellet quantity increased while pellet size decreased. The opposite trend occurred with increasing substrate viscosity. Among these parameters, rotation speed exerted the most significant effect on both morphology regulation and pellet formation. The addition of coconut meat resolved the issue of no mycelia formation (including pellets) in coconut milk. It also enabled uniform pellet production in both coconut milk and coconut water. When coconut meat was added to coconut milk, the average pellet diameter was 3.5 mm, and the average pellet number was 3.34 × 10⁵ pellets/L. This study contributes to the development of a novel functional food research field. It provides a potential method for producing uniform mycelia pellets.