Metabolomic insights into polyhydroxyalkanoates production by halophilic bacteria with acetic acid as carbon source

A metabolomics method was established to analyze changes of intracellular metabolites and study the mechanism for enhancing polyhydroxyalkanoates production by halotolerant bacteria, Bacillus cereus strain HY-3, using acetic acid as carbon source. Maximum poly(3-hydroxybutyrate) (PHB) contents for the medium with 0.5 g/L and 5.0 g/L of acetic acid were 41.0 ± 0.415% and 49.2 ± 1.21%. Principal components analysis revealed clear metabolic differences in different growth stages and different concentrations of carbon source. According to statistical analysis, 3-hydroxybutyrate (3-HB), serine, threonine, malate, and pyruvate were determined as potential biomarkers for PHB production. Moreover, metabolic pathways analysis indicated that high level of 3-HB in death phase was due to the limitation of carbon source. Metabolism of glycine, serine, and threonine was influential pathway for PHB production among amino acid metabolisms. High levels of organic acids from the TCA cycle could stimulate the carbon source flux into PHB biosynthetic pathway. Metabolomics method based on GC/MS was used to analyze metabolites, aiming to find out biomarkers and reveal mechanism for enhancing PHA production.