Optimization of compound amino acid medium for Lentinula edodes and the effect on mycelial growth and physiology

Abstract:

[Background] L-amino acid supports the growth and development of Lentinula edodes as a nutrient. It is of great significance for the high-production and high-quality development of L. edodes industry to optimize the growth substrate of L. edodes by adding amino acids. [Objective] Exogenous alanine (Ala), serine (Ser), and asparagine (Asn) were used to improve the medium, and the possible metabolic pathway of the compound amino acids to promote the growth of L. edodes mycelia was explored. [Methods] The three-factor, three-level Box-Behnken design was employed to optimize the concentration of the amino acids, with the evaluation indicator of mycelial growth rate, and a series of physiological indexes of L. edodes mycelia in the optimized medium were determined. [Results] The theoretical optimal concentration of Ala, Asn, and Ser was 174.711 mg/L, 113.826 mg/L, and 5.661 mg/L, respectively, and the formula was verified to effectively promote the growth of L. edodes mycelia. Compared with potato dextrosa agar (PDA), the optimized medium enabled high content of pyruvic acid (PA) and protein, significantly high activity of glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT), and low content of malondialdehyde (MDA) in L. edodes mycelia. [Conclusion] The study provides a theoretical reference for the improvement of L. edodes medium and the mechanism of amino acids promoting mycelial growth.