Construction of Coculture System Containing Escherichia coli with Different Microbial Species for Biochemical Production

Abstract

Microbial synthesis of target chemicals usually involves multienzymatic reactions in vivo, especially for compounds with a long metabolic pathway. However, when various genes are introduced into one single strain, it leads to a heavy metabolic burden. In contrast, the microbial coculture system can allocate metabolic pathways into different hosts, which will relieve the metabolic burdens. Escherichia coli is the most used chassis to synthesize biofuels and chemicals owing to its well-known genetics, high transformation efficiency, and easy cultivation. Accordingly, cocultures containing the cooperative E. coli with other microbial species have received great attention. In this review, the individual applications and boundedness of different combinations will be summarized. Additionally, the strategies for the self-regulation of population composition, which can help enhance the stability of a coculture system, will also be discussed. Finally, perspectives for the cocultures will be proposed.

Establishment of synthetic microbial consortia with Corynebacterium glutamicum and Pseudomonas putida: Design, construction, and application to production of γ‐glutamylisopropylamide and l‐theanine

“…Providing an additional carbon source that is only accessible to one partner of the consortium may also be used for fine‐tuning (Pan et al., 2023 ). Since alternative carbon sources are generally interesting in order to prevent competition with human and animal nutrition or to decrease the cost of the process, a number of bacteria, including P. putida and C. glutamicum , have been engineered for the utilisation of non‐native carbon sources (Wendisch et al., 2016 ).…”

“…For the design of these synthetic consortia, the interactions, mechanisms and structures of natural inter‐ and intrakingdom consortia need to be studied and understood (Zhang et al., 2018 ). Synthetic microbial consortia have several advantages over monocultures, for example due to the division of labour; reduction of metabolic loads; avoidance of the influence of different functions; optimal catalytic environments for enzymes derived from different sources; balance of cofactor and energy levels; higher adaptability and stability to environmental fluctuations (Harcombe et al., 2018 ; Pan et al., 2023 ; Shong et al., 2012 ). Most biotechnological processes are based on feedstocks, which are homogenous and continuously available, and thus, specialised monocultures can be used.…”

“…Production of bioactive compounds by consortia may support plug‐and‐play biosynthesis: strains used in co‐cultures are genetically designed to adapt to each biosynthesis pathway module more precisely than monocultures to the entire pathway, and the consortium is optimised in host selection, construction of module pathways, initial ratio of strains and culture conditions (Thuan et al., 2022 ). For best production, the selection of the intermediate metabolic node is necessary and important for balancing cofactor and energy supply (Li et al., 2019 ; Pan et al., 2023 ). To establish robust processes of synthetic consortia, different levels of interdependency through cross‐feeding or auxotrophies can be used: no interaction (0/0), competition (−/−), commensalism (0/+) or mutual cooperation (+/+) (Sgobba & Wendisch, 2020 ).…”

Programming Dynamic Division of Labor Using Horizontal Gene Transfer

“…Separating the steps of the pathway reduces the burden on each subpopulation, allowing for each subpopulation to commit more resources to its specific task. If the increase in productivity due to specialization and the additional accumulation of productive biomass outweighs the reduced metabolic efficiency due to the need for the transport of intermediates between subpopulations, then an SDOL system will outperform the analogous monoculture. , Indeed, studies have demonstrated SDOL as a viable approach for executing complex functions. − However, stabilizing interstrain competition often requires the implementation of population ratio controllers to prevent the extinction of members of the consortium. − …”