Linking environmental cues to genomic responses for enhanced production and recovery of Bacillus bacteriocins via ammonium sulphate precipitation: a review

Bacillus species are widely used in food fermentation and are known producers of antimicrobial peptides, including bacteriocins. These compounds offer broad-spectrum antimicrobial activity, processing stability, and low mammalian toxicity, making them promising agents for food biopreservation. However, their commercial potential remains underexploited due to low production yields and inefficient downstream recovery. This review presents a comprehensive optimisation framework that encompasses both upstream production and downstream recovery using ammonium sulphate precipitation. It examines the influence of medium composition (carbon and nitrogen sources) and cultivation conditions (pH, temperature, aeration, agitation, and incubation period) on bacteriocin production. Mechanistic insights are provided by linking environmental cues to genomic responses involved in bacteriocin biosynthesis, offering a baseline for predictive and strain-specific production strategies. Unlike empirical studies, gene expression data offer greater specificity by isolating bacteriocin-related activity from other antimicrobial effects. The review further proposes an optimised, scalable framework for ammonium sulphate precipitation, enabling parallel screening of key parameters. This systematic approach replaces conventional trial-and-error methods, reducing optimisation time and improving reproducibility across diverse Bacillus strains. Overall, the evidence synthesised in this review highlights key mechanistic pathways and operational variables that should be investigated further to refine bacteriocin production and recovery strategies.