Engineering glucose uptake for enhanced production of L-tyrosine in Bacillus amyloliquefaciens.

Abstract

L-Tyrosine is an important aromatic amino acid widely used in dietary supplements and as a precursor for high-value food ingredients. Microbial fermentation presents a sustainable and green production route, but achieving high titers remains challenging due to incomplete understanding of metabolic regulation. In this study, Bacillus amyloliquefaciens was engineered for efficient L-tyrosine production to support its application in functional food development. Systematic investigation of the glucose transport pathway identified two key genes of the non‑phosphotransferase system, namely glcP1 (glucose permease) from B. amyloliquefaciens and glK (glucokinase) from Corynebacterium glutamicum. Overexpression of these genes increased L-tyrosine titers to 395.82 mg/L and 385.37 mg/L, representing 36% and 33% improvements, respectively. Subsequent optimization of expression elements (promoters, terminators, and 5'-UTRs) further enhanced production to 458.27 mg/L. Furthermore, glucose uptake and phosphorylation were reconstructed by combining non‑PTS enhancement with PTS attenuation. The resulting chassis strain (B52) produced 407.16 mg/L, a 43% increase over the wild‑type strain B1. Finally, overexpression of the rate‑limiting enzymes AroA and TyrA raised the titer to 1400.53 mg/L. This study provides effective metabolic engineering strategies for the biosynthesis of L-tyrosine in non-model Bacillus species and offers a promising approach for the sustainable production of amino acids.