A Comprehensive Review: Harnessing Functional Microbiota for Precision Fermentation of Foods

Microbial consortia dictate the quality, safety and functional properties of fermented foods, yet the inherent variability of spontaneous fermentations limits product standardization and industrial scalability. This review assesses technologies for (i) isolating and characterizing functional microbes, (ii) precision engineering of strains, and (iii) integrating engineered microbes into tightly controlled fermentations, evaluating achievements, constraints, evidence reliability, and short-/long-term priorities. Function‑oriented screening strategies-including stress‑tolerant, flavor‑oriented, safety‑oriented and metabolism‑oriented methods-are compared, revealing that most investigations rely only on phenotypic or gene‑presence data without confirming in situ metabolite production. Directed mutagenesis and synthetic community engineering, principally via CRISPR‑Cas systems, enable scar‑less genome edits, yet regulatory hurdles, off‑target risk assessments and consumer acceptance remain unresolved, and the stability of synthetic consortia during scale‑up is uncertain. Emerging domains such as uncultured‑taxa mining with Microbe‑seq and AI‑guided media design show promise, but current isolation efficiencies constrain applicability; CRISPR‑based pathway regulation offers fine‑tuned control, but quantitative genotype‑to‑flux models are still immature, and safety‑evaluation frameworks lack harmonized strain‑level criteria. A four‑component definition of “precision fermentation” is proposed, and an evidence‑hierarchy framework guides the prioritization of short‑term actions and long‑term trajectories. The review thus aims to transition the field from descriptive cataloguing toward mechanistic, reproducible and scalable biotechnological solutions.