Objective Use of waste material from tea bush pruning in formulating substrate for cultivating Ganoderma lucidum was optimized based on the resulting mushroom development, quality, and operation economy.

Method Cut branches and leaves collected from tea bush pruning were added at equal mass proportion of 20% (PF-1), 40% (PF-2), 60% (PF-3), 80% (PF-4), 100% (PF-5), or 0% (CK) to replace wood chips in the conventional culture substrate for cultivating herbal mushroom G. lucidum. Under the same cultivation conditions, growth, quality, and input-output of mushroom fruiting bodies harvested under the treatments were determined for comparison.

Result (1) On mushroom morphology and operational economy‌: G. lucidum cultivated on the substrates of treatments grew normally without deformities but the normal bright red color like CK. The mycelia developed the fastest under PF-5 at a rate of 0.99 mm·d⁻¹, which differed significantly from those under CK or PF-1 (P<0.05). PF-1 produced the most-appealing fruiting bodies with the cap length, width, and thickness increased by 27.22%, 18.50%, and 9.77%, respectively, over CK and a highest 16.59% single-bag yield of 59.46 g·bag⁻¹ among all (P<0.05). In addition, the various treatments improved the cultivation biological efficiency (BE) by 25.07-31.66% over CK, with PF-1 boosting to the highest level at 4.99%. (2) On nutrients in fruiting body‌: The crude fat, polysaccharides, triterpenes, and sterols were higher under the treatment than CK but not significantly different between the treatments (P>0.05); the crude protein, lowered under PF-4 and PF-5 (P<0.05); and the crude fiber, significantly higher under PF-4 (P<0.05) but only slightly under PF-5. (3) On amino acids: The contents of essential amino acids (EAA) in the treatment samples were 0.16-5.05 times of CK, with the highest found in those harvested from PF-4; the EAA/total AA (TAA) and EAA/non-essential AA (NAA) ratios, 0.18-1.53 times and 0.18-2.3 times, respectively, of CK; the umami, sweet, and bitter AAs (except PF-5), as well as the aromatic AAs, higher than those under CK; and the greatest umami AA/bitter AAs ratio, existed in the sample under PF-3, while the sweet AAs/aromatic AAs, in that under PF-4. (4) ‌On financial analysis‌: The input-output ratios of the treatments were 81.87-115.69% higher than those of CK (P<0.05), but not significantly different among the treatments (P>0.05)

Conclusion Taking nutrient contents, amino acid indexes, and economic evaluation into considerations, ‌PF-4, which substituted 80% of wood chips with the bush pruning discards from tea plantations for G. lucidum cultivation, appeared to be the formulation of choice.