DOE-guided assembly and optimization of Synthetic Microbial Communities for bacterial cellulose production

Abstract Bacterial cellulose (BC) is a biopolymer boasting potential applications in food and biomedical fields. Although acetic acid bacteria (AAB) are recognized as high BC-producers, several factors may affect the amount produced, making the BC synthesis variable and strain-dependent. Therefore, strategies to improve BC production are of practical relevance. In this study, 12 synthetic microbial communities (SynComs), consisting of acetic acid bacteria (AAB) and/or lactic acid bacteria (LAB) and/or yeasts (Y) were assembled and tested to boost BC production. Specifically, a sequential chemometric strategy based on two Plackett-Burman designs (PBDs) and a circumscribed central composite design (CCC) was implemented to construct and screen SynComs, as well to optimize the culture conditions for BC production. The design of experiments (DOE) approach used in this study allowed for the identification of a suitable SynCom (including both LAB and Y as helper strains) that, in the optimized conditions (50 g/L glucose, 32 °C, 7 days) reached a BC titre (10.40 ± 0.40 g/L) comparable with that of the best BC-producer (AAB monoculture Δgdh K2G30; BC titre 10.79 ± 0.36 g/L). The optimized level, moreover, was consistent with the BC production predicted by the CCC regression model (10.53 g/L). Although further metabolic and population dynamics analyses are required to elucidate the roles and interactions among the community members, our results offer a new perspective on the use of model microbial consortia for BC synthesis and underlines their potential for the development of future and more versatile processes. Key points • PBD and CCC sequential designs are useful for SynComs assembly and optimization • The composition of SynComs significantly affects the BC production • Several SynComs are more effective than some AAB monocultures for BC production