Living materials with programmable functionalities grown from engineered microbial co-cultures

Abstract

Biological systems assemble tissues and structures with advanced properties in ways that cannot be achieved by man-made materials. Living materials self-assemble under mild conditions, are autonomously patterned, can self-repair and sense and respond to their environment. Inspired by this, the field of engineered living materials (ELMs) aims to use genetically-engineered organisms to generate novel materials. Bacterial cellulose (BC) is a biological material with impressive physical properties and low cost of production that is an attractive substrate for ELMs. Inspired by how plants build materials from tissues with specialist cells we here developed a system for making novel BCbased ELMs by addition of engineered yeast programmed to add functional traits to a cellulose matrix. This is achieved via a synthetic 'symbiotic culture of bacteria and yeast' (Syn-SCOBY) approach that uses a stable co-culture of Saccharomyces cerevisiae with BC-producing Komagataeibacter rhaeticus bacetria. Our Syn-SCOBY approach allows inoculation of engineered cells into simple growth media, and under mild conditions materials self-assemble with genetically-programmable functional properties in days. We show that co-cultured yeast can be engineered to secrete enzymes into BC, generating autonomously grown catalytic materials and enabling DNA-encoded modification of BC bulk material properties. We further developed a method for incorporating S. cerevisiae within the growing cellulose matrix, creating living materials that can sense chemical and optical inputs. This enabled growth of living sensor materials that can detect and respond to environmental pollutants, as well as living films that grow images based on projected patterns. This novel and robust Syn-SCOBY system empowers the sustainable production of BC-based ELMs..

Modular biosynthesis of plant hemicellulose and its impact on yeast cells

“…In addition to these natural polysaccharides, which have been used by humans for centuries, microbes can now be modified to produce engineered living materials with entirely new functions (Gilbert and Ellis, 2019). In a recent landmark study, cellulose functionalized with enzymes or optogenetic sensors was produced by the co-culture of Komagataeibacter rhaeticus bacteria and engineered yeast (Gilbert et al, 2021).…”

“…Greater interest in the engineering of polysaccharide-based biomaterials has emerged in recent years. Synthetic biology efforts in this area have been largely restricted to bacterial cellulose due to its well-characterized production (Gilbert and Ellis, 2019;Gilbert et al, 2021). Although suitable orthogonal hosts have been identified (Pauly et al, 2019), comparatively little is known about how the biosynthesis of plant hemicelluloses by glycosyltransferases (GTs) could be reconstituted and modulated in non-plant cell factories.…”

Versioning Biological Cells for Trustworthy Cell Engineering

“…Engineering biology is exploding with advances ranging from new genome editing tools (1), to genetically encodable materials for advanced sensing of cells physiological states, electrical fields and mechanical stresses (2, 3), programmable and functional microbial-based living materials (4), environmental remediation and pollution control (5) to advanced in vivo data storage (6). Moreover, these advances in fundamental science are rapidly translating into new companies (7) and consumer products (8), which within the first half of this century, are set to impact most areas of our lives.…”

Programmable Microbial Ink for 3D Printing of Living Materials Produced from Genetically Engineered Protein Nanofibers

“…[1][2][3] The emerging field of living materials has leveraged microbial engineering to produce materials for various applications, but building 3D structures in arbitrary patterns and shapes has been a major challenge. [1][2][3][4][5][6][7][8][9][10][11][12][13][14] We set out to develop a new bioink, termed as "microbial ink" that is produced entirely from genetically engineered microbial cells, programmed to perform a bottom-up, hierarchical self-assembly of protein monomers into nanofibers, and further into nanofiber networks that comprise extrudable hydrogels. We further demonstrate the 3D printing of functional living materials by embedding programmed Escherichia coli (E. coli) cells and nanofibers into microbial ink, which can sequester toxic moieties, release biologics and regulate its own cell growth through the chemical induction of rationally designed genetic circuits.…”