Adaptive Laboratory Evolution of Simplified Microbial Consortia: Mechanisms, Experimental Frameworks and Applications

Microbial bioprocesses based on monocultures can be constrained by the substrate range, metabolic burden and stress tolerance of individual strains. Simplified microbial consortia, composed of a limited number of characterised members, can distribute metabolic tasks and enable interactions such as cross-feeding and division of labour. This review examines adaptive laboratory evolution (ALE) in these systems, with emphasis on co-evolutionary, modular and hybrid experimental frameworks. We distinguish evidence obtained with defined multispecies consortia from adjacent evidence derived from enrichment communities, ALE-like selection systems and intraspecific multi-lineage populations. Across these systems, ALE can alter genetic, regulatory and ecological processes that influence resource partitioning, stress tolerance and community performance, although direct mechanistic evidence remains limited and taxonomically narrow. We critically assess applications in pollutant degradation, lignocellulosic biomass and lignin conversion, high-value compound biosynthesis and waste valorisation, considering their degree of technological validation. Finally, we discuss how longitudinal multi-omics, metabolic modelling and automated experimentation may improve the predictability, reproducibility and industrial relevance of consortium ALE.