Bioscience Evidence 2026, Vol.16, No.4, 316-328 http://bioscipublisher.com/index.php/be 318 hardwood materials such as Populus ciliata and Mangifera indica supported better production performance. In addition, different wood substrates affected ergosterol accumulation and the potential formation of vitamin D₂. Using only one type of sawdust does not always result in the best production performance. Reasonable mixing of different wood materials can improve substrate properties. A mixture of oak and eucalyptus substrates increased the biological efficiency of shiitake cultivation, and the combination of oak, eucalyptus, and wheat bran showed better production performance (El Sebaaly et al., 2024). With the continuous expansion of shiitake production, the supply pressure of high-quality traditional sawdust resources has gradually increased. Agricultural and forestry residues have therefore attracted increasing attention as alternative substrate materials. Sassine et al. (2024) evaluated the application of woody residues, including acorns, grape branches, and olive branches, in shiitake substrates. The results showed that some properly formulated alternative materials could achieve production performance close to that of traditional oak sawdust. 2.3 Nutrient supplementation strategies Using sawdust alone often results in insufficient nutrient supply, especially due to low nitrogen and mineral contents, which cannot fully support long-term mycelial growth and fruiting body development. Therefore, adding appropriate nutrient supplements to sawdust-based substrates is an important strategy for improving shiitake production performance. Currently, wheat bran and rice bran are the most widely used nutrient supplements in shiitake cultivation. These cereal by-products contain relatively high levels of proteins, minerals, and vitamins, which can improve substrate nutrition, promote mycelial expansion, and enhance later fruiting. Paswal et al. (2024) conducted a study in the Jammu region of India and found that a substrate containing wheat straw combined with wheat bran showed better nutritional characteristics than sawdust alone. The contents of crude protein, crude fat, crude fiber, and total carbohydrates reached 22.44%, 3.97%, 7.69%, and 63.50%, respectively. Different types of supplements also show different effects on shiitake production. Shanmugaraj et al. (2025) compared several nutrient supplements and found that wheat bran treatment resulted in higher fruit body weight and biological efficiency, followed by rice bran, while some other supplements showed relatively lower effects. Desisa et al. (2023) investigated the effects of different nutrient supplementation strategies in agricultural waste-based substrates. The S4 treatment, based on sugarcane bagasse supplemented with 20% poultry manure, showed the best performance, with a fresh mushroom yield of 434.33 g per 500 g substrate, a biological efficiency of 86.83%, and continuous production of five flushes. This treatment also resulted in higher protein, fiber, and fat contents of the fruiting bodies (Desisa et al., 2024) (Figure 1). 2.4 Carbon-nitrogen balance and substrate performance During cultivation, carbon in the substrate is mainly used for mycelial growth and energy supply, while nitrogen participates in mycelial formation, enzyme synthesis, and fruiting body development. The balance between carbon and nitrogen directly affects mycelial growth rate, bag maturation time, and later fruiting performance. However, a higher C/N ratio or increased nitrogen content does not always lead to better production. An appropriate balance is required. Nutrient supplements such as wheat bran and rice bran not only provide additional nutrients but also help regulate the C/N ratio, creating a more suitable environment for long-term shiitake growth. Different substrate systems may require different C/N conditions. In agricultural waste-based substrates, crop residues usually contain high carbon levels but relatively low nitrogen levels, and additional nitrogen sources are often needed to improve nutrient utilization efficiency. However, the relationship between C/N ratio and shiitake yield is not simply linear. Chen et al. (2022) studied the effects of hardwood substrates and different nitrogen supplementation levels on shiitake production and found that nitrogen supply significantly influenced lignocellulose degradation and yield formation. Although substrates without nitrogen supplementation showed faster mycelial expansion, the highest yield was not obtained in this treatment but occurred after adding an appropriate amount of whey nitrogen source.
RkJQdWJsaXNoZXIy MjQ4ODYzNA==