Design of synthetic microbial cocultures for advanced biomanufacturing of lignocellulosic biofuels and bioproducts

Abstract

Microbial fermentation is a key technology for efficient conversion of lignocellulosic resources into various value-added products. The use of synthetic microbial cocultures is rapidly emerging as a powerful strategy to overcome fundamental limitations of monoculture-based lignocellulose fermentation. By distributing complex tasks such as lignocellulose depolymerization, inhibitor detoxification, mixed-sugar utilization, and product formation across complementary microbial specialists, cocultures can alleviate metabolic burden, improve substrate and product coverage, and enhance process robustness against variable feedstock quality and inhibitor loads. Therefore, advancing microbial coculture design and implementation will enable more efficient and scalable microbial conversion of lignocellulose. This tutorial review outlines general design principles for synthetic microbial cocultures, highlighting four central design objectives: division of labor, flexible product formation from heterogeneous substrates, enhanced robustness, and programmable control of community population and function. Within this framework, coculture architectures are examined in terms of how they can be tailored to distinct lignocellulosic pretreatment strategies and process configurations, with recent case studies being used to illustrate enhanced carbon utilization, inhibitor tolerance, and multiproduct valorization from diverse biomass hydrolysates. Furthermore, emerging tools in modeling, synthetic biology, and advanced fermentation are converging to integrate ecological design with process systems engineering, enabling data-driven coculture processes that advance a circular bioeconomy and reduce the environmental footprint of chemical production. At the same time, coculture-based lignocellulosic fermentation introduces additional complexity compared with conventional monoculture processes, creating technical challenges in strain stability, process control, downstream separations, and scale-up that must be actively addressed for successful deployment. It is crucial to more clearly quantify the benefits of coculture strategies in defined industrial contexts through techno-economic analysis (TEA) and life-cycle assessment (LCA), linking biological performance to cost, energy, and environmental metrics. Collectively, this review connects advances in microbial coculture engineering and their underlying design principles to greener, cost-competitive biomanufacturing by decreasing dependence on harsh chemical processes, improving resource utilization, and upgrading renewable lignocellulosic feedstocks into sustainable products.