Project description:FROG and miniFROG reports are given for the genome-scale metabolic network of Bacillus licheniformis WX-02. The model iWX1009 contains 1009 genes, 1141 metabolites and 1762 reactions and is the study of poly-γ-glutamic acid (γ-PGA) synthesis. The model can be found in the Supplementary data of the Guo et al, 2016 paper cited here.
2024-10-15 | MODEL2408030002 | BioModels
Project description:Effects of poly-gamma-glutamic acid application on soil bacterial community composition
Project description:Drought stress is the main factor restricting maize yield. Poly-γ-glutamic acid (γ-PGA) could significantly improve the drought resistance and yield of many crops. However, its high production costs and unclear long-term impact on soil ecology limit its large-scale application. In this study, genes (PgsA, B, C) that participate in γ-PGA synthesis were cloned from Bacillus amyloliquefaciens and transformed into maize for the first time. Under drought stress, transgenic maize significantly increased the ear length, ear weight and grain weight by 50% compared to the control, whereas the above yield characteristics increased by 2.33, 13.06, 19.34 and 18.36%, respectively under normal growth conditions. γ-PGA was mainly expressed in the mesophyll cells of maize leaf rosette structure and improved drought resistance and yield by protecting and increasing the expression of genes for the photosynthetic and carbon fixation. This study is an important exploration for maize drought stress molecular breeding and building resource-saving agriculture.
Project description:The industrially attractive biopolymer Poly-γ-glutamic acid (γ-PGA) is commonly produced by species of the genus Bacillus by co-feeding different carbon- and nitrogen sources. Recent studies have highlighted the pivotal role of co-metabolization of a rapidly degradable carbon source such as glycerol together with citrate for γ-PGA production, independently fueling biomass generation as well as TCA cycle precursor supply. With this study, we report that the sole presence of citrate in the production medium greatly influences growth behavior, γ-PGA production, and the viscosity of microbial cultures during biopolymer synthesis. Independent of the citrate concentration in the medium. only minor amounts of citrate were imported by B. subtilis 168 in presence of glycerol due to carbon catabolite repression. However, a high citrate concentration resulted in a 6-fold increase in γ-PGA titer as compared to low levels of exogenous citrate. Data suggests that citrate was not used as a precursor in γ-PGA synthesis but rather influenced the fate of imported glutamate. The citrate concentration also affected medium viscosity as depletion resulted in a remarkable spike in broth viscosity. Additionally, cellular proteome analysis at different levels of citrate availability revealed significant changes in protein abundance involved in motility and fatty acid degradation
Project description:Biofilms are well organized, cooperating communities of microorganisms encased in a self-produced extracellular matrix, providing resilience against external stress such as antimicrobial agents and host defenses. A hallmark of biofilms is their phenotypic heterogeneity, which enhances the overall growth and survival of the community. In this study, we demonstrate that removing the genes encoding the key molecular chaperones DnaK and trigger factor disrupts protein homeostasis in Bacillus subtilis and leads to the formation of extremely mucoid biofilms with aberrant architecture, compromised structural integrity, and altered phenotypic heterogeneity. These changes include a drastic reduction in the motile subpopulation and an overrepresentation of matrix producers and endospores. Overproduction of poly-γ-glutamic acid contributed crucially to the mucoid phenotype and aberrant biofilm architecture. Elevated temperatures led to protein homeostasis impairment resulting in mucoid and aberrant biofilm phenotypes. Our findings suggest that disruption of protein homeostasis, whether due to the absence of molecular chaperones or environmental factors, constrain biofilm formation.