Chameleon-like microbes promote microecological differentiation of Daqu.

Chameleon-like microbes in the fermentation community are an internal factor that facilitate the transformation of the community to the corresponding homeostasis states under specific environmental conditions. High temperature daqu can form three typical microecologies during the preparation process, making it an ideal system for studying chameleon-like microbes. This study integrated multi-omic methods such as metaproteomics, and determined that Neurospora crassa, Aspergillus nidulans, Bacillus subtilis and Oceanobacillus iheyensis were chameleon-like microbes that regulated the metabolic differences of five-member heterocyclic amino acids in daqu, resulting in microecological differentiation. Synthetic microbial consortia consisting of the four chameleon-like microbes with (T6) and without (T4) the dominant functional bacteria Saccharopolyspora erythraea and Virgibacillus haloimitrificans were fermented under simulated in situ conditions. The community constructed by microorganisms with greater functional diversity (T6) was more robust, and its metabolome was more similar to the in situ system. When exposed to environmental disturbances, the functional diversity helped to maintain the community stability by increasing the dissimilarity of chameleon-like microbes in the community and forming different homeostasis.