Spent broth of Micromonospora sp. TBJPDA3, a sporocarp bacterium of Calocybe indica, improved mushroom spawning in sawdust substrate

Abstract

Calocybe indica is a potential tropical edible mushroom with an attractive taste and a high nutritional value. To obtain a desired harvest, the mycelia should be spawned in the entire sawdust substrate before proceeding to the next step. However, the spawning rate of this mushroom is considerably low. Recently, bacteria isolated from the sporocarp of mushrooms attracted many attentions due to their ability to specifically promote the mycelial growth of their fungal host via the production of metabolites. Therefore, the aim of this study was to accelerate the spawning run of C. indica by using a crude extract of its sporocarp bacterial metabolite. Two isolates with a significant mycelial growth promotion were employed, namely TBJPDA3 and TBJPDA4. The spent broth (SB) of TBJPDA3 and TBJPDA4 significantly stimulated the mycelial growth of C. indica in agar plate by 26.85 and 18.33 %, respectively. In sawdust medium, the SB of TBJPDA3 increased 28.83 % of the mycelial growth. Furthermore, the presence SB of TBJPDA3 in sawdust substrate also increased 26.13, 100.00, and 30.98 % of laccase, lignin peroxidase, and manganese peroxidase activity of the fungus, respectively. The strain of TBJPDA3 was molecularly identified as Micromonospora sp. The untargeted metabolomic toward SB of TBJPDA3 showed collection of some potential carbonecous and nitrogenous compounds. In conclusion, Micromonospora sp. TBJPDA3 and its metabolites were prospective for sustainable C. indica cultivation through accelerating bioconversion of sawdust substrate.