Impact of culture conditions and cultivation models on mycelial growth, agronomic traits and bioactive compounds of Ganoderma suae.

Ganoderma species have a long history in traditional medicine and possess considerable medicinal, economic and ecological value. Strain HL163 was isolated from wild basidiomata of Ganoderma collected in Yunnan Province, China, and identified as Ganoderma suae based on morphological characteristics and ITS-sequence-based molecular analysis. Nevertheless, knowledge of its cultivation traits and bioactive compounds remains limited. This study aimed to systematically characterise its biological features, cultivation adaptability under diverse systems, and bioactive compound profiles. The effects of carbon source, nitrogen source, temperature,pH value and inorganic salt on growth of the mycelium were investigated by single factor test and three optimal levels were selected for orthogonal test to investigate effects of different culture conditions on the growth of mycelia. Subsequently, bag-cultivation trials were conducted under three cultivation models: facility greenhouse soil-covered cultivation, understory soil-covered cultivation, and shelf three-dimensional cultivation. Agronomic traits and bioactive compound contents of mature basidiomata and spore powder were compared across these cultivation systems. Single factor test showed that the suitable growth temperature, initial pH, carbon source, nitrogen source and inorganic salt were 30 °C, pH 5.5, glucose, soybean peptone, and MgSO4, respectively. The orthogonal test indicated that the suitable combination was temperature of 30 °C, carbon source of maltose, nitrogen source of soybean peptone, and inorganic salt of MgSO4. The influence strength of each factor on mycelial growth was ranked as follows: carbon source > temperature > inorganic salt > nitrogen source > pH. The suitable culture medium for bag cultivation consisted of 79 %, mixed-wood sawdust of Quercus, 18 % wheat bran, 1 % gypsum, and 2 % sucrose, with substrate moisture maintained at 50 %-55 %. During the mycelial stage under dark conditions at 25-30 °C, the full-bag period was 23 to 30 d, and the average mycelial growth rate was 1.16-1.52 cm/d. Under the three cultivation models, the primordium formation period of G. suae was 20 to 35 d, the average dry weight yield of fruiting bodies was 23.76 g/bag, and the entire cultivation cycle was approximately 85 to 135 d. The understory cultivation model achieved the highest biological efficiency of 11.73 %, which was 0.69 percentage points higher than shelf three-dimensional cultivation 11.04 %. Mature fruiting bodies had mean total triterpenoid content of 1.54 % and polysaccharides content of 0.90 %. Spore powder showed a markedly lower total triterpenoid content 0.16 %, representing an approximately 9.63-fold reduction relative to fruiting bodies, whereas its polysaccharides content 1.00 % was slightly higher. This study provides scientific evidence for the exploration and utilization of characteristic edible-medicinal fungal resources and expands the germplasm repository for selective breeding within Ganoderma.