Getting Bacteria in Shape: Synthetic Morphology Approaches for the Design of Efficient Microbial Cell Factories

Supported by the tools of contemporary synthetic biology, the field of metabolic engineering has advanced in its overarching purpose of contributing efficient bioprocesses for the synthesis of biochemicals by addressing a number of cell and process parameters. The morphology and spatial organization of bacterial biocatalysts has been somewhat overlooked in such endeavors. The shape, size, and surface features of bacteria are maintained over evolutionary timescales and, under tight control of complex genetic programs, are faithfully reproduced each generation-and offer a phenomenal target for manipulations. This review discusses how these structural traits of bacteria can be exploited for designing efficient biocatalysts based on specific morphologies of both single cells and natural and artificial communities (e.g., catalytic biofilms). Examples are presented on how morphologies and physical forms of bacterial cell factories can be programmed while engineering their biochemical activities. The concept of synthetic morphology opens up strategies for industrial purposes and holds the potential to improve the economic feasibility of some bioprocesses by endowing bacteria with emergent, useful spatial properties. By entertaining potential applications of synthetic morphology in the future, this review outlines how multicellular organization and bacterial biorobots can be programmed to fulfill complex tasks in several fields.