Combined application of multi-omics techniques and multivariate statistical analysis reveals the core functional microorganisms of Qula in Tibet, China

Abstract

Tibetan Qula, a traditional fermented food processed from yak milk, is valued for its high nutritional content and distinctive flavor, but the vast territory of Tibet often results in quality heterogeneity. To identify the core microorganisms with metabolic activities in Qula, we conducted a comprehensive investigation of 10 samples from 7 regions of Tibet using integrated multi-omics techniques and multivariate statistical analysis. All samples were higher in protein content (36.43∼60.25%), acidity (86.72∼216.52 °T) and lactic acid bacteria count (3.69∼6.14 logCFU/g), while lower in fat (2.40∼11.35%) and moisture contents (5.84∼12.02%). High-throughput sequencing showed significant differences in microbial diversity and community composition among samples, but Lactococcus, Lactobacillus, Leuconostoc, Acetobacter, Penicillium and Aspergillus were core microorganisms due to their high abundance and wide distribution. Notably, they also played an important role in maintaining community interactions, especially Acetobacter. Of the 60 volatiles detected by GC-MS, 23 compounds such as hexanal, heptanal, butanoic acid, hexanoic acid and ethyl octanoate were identified as the dominant flavors. In contrast, the 62 non-volatiles obtained from metabolomics were primarily composed of carbohydrates, organic acids, fatty acids and amino acids, with lactose, lactic acid, palmitic acid and alanine being the most abundant metabolites in their respective categories. Correlation analysis indicated that core microorganisms were predominantly involved in the formation and transformation of metabolites, while Lactococcus, Rhodotorula and Trichothecium facilitated the accumulation of various flavors. This study provides a comprehensive analysis of the microbial and metabolic characteristics of Tibetan Qula, offering a scientific foundation for quality enhancement through biofortification technology.