Hyper-porous encapsulation of microbes for whole cell biocatalysis and biomanufacturing.

Abstract

Biocatalysis using whole cell biotransformation presents an alternative approach to producing complex molecules when compared to traditional synthetic chemical processes. This method offers several advantages, including scalability, self-contained co-factor recycling systems, the use of cost-effective raw materials, and reduced purification costs. Notably, biotransformation using microbial consortia provides benefits over monocultures by enhancing biosynthesis efficiency and productivity through division of labor and a reduction in metabolic burden. However, reliably controlling microbial cell populations within a consortium remains a significant challenge. In this work, we address this challenge through mechanical constraints. We describe the encapsulation and immobilization of cells in a hyper-porous hydrogel block, using methods and materials that are designed to be amenable to industrial scale-up. The porosity of the block provides ample nutrient access to ensure good cell viability, while the mechanical properties of the hydrogel matrix were optimized for Escherichia coli encapsulation, effectively limiting their proliferation while sustaining recombinant protein production. We also demonstrated the potential of this method for achieving stable co-cultivation of microbes by maintaining two different microbial strains spatially in a single porous hydrogel block. Finally, we successfully applied encapsulation to enable biotransformation in a mixed culture. Unlike its non-encapsulated counterpart, encapsulated E. coli expressing RadH halogenase achieved halogenation of the genistein substrate in a co-culture with genistein-producing Streptomyces. Overall, our strategy of controlling microbial cell populations through physical constraints offers a promising approach for engineering synthetic microbial consortia for biotransformation at an industrial scale.