Engineering Microbiomes-Looking Ahead.

M the collective of microbes within a community, shape the natural world. They exist in, on, and around nearly every organism and environment on Earth. Microbiomes interact with their environments in key ways, forming dynamic relationships and interactions with biotic and abiotic elements of their environments. Over the past 20 years, advances in sequencing and -omics technologies have helped transform microbiome research from limited snapshots of microbial community composition to reveal vibrant, dynamic panoramas of microbiomes and their interactions. Now, new tools to manipulate and grow communities in the lab, perform large-scale, high-throughput experiments, and better understand the roles of different constituent community members, make the prospect of engineering microbiomes a challenging but achievable goal for the next 20 years. The engineering of microbiomes could facilitate revolutionary changes in food production, human and animal health, and environmental preservation and restoration. Engineered microbiomes could reduce or eliminate the need for environmentally damaging fertilizers, while facilitating increased disease resistance in staple crops. Personalized human microbiomes may help prevent diseases or even enhance human health. Ocean microbiomes can be engineered to reduce and mitigate plastic and microplastics pollution. Together, these and many other applications of engineered microbiomes hold the potential to transform our world. To help achieve the future we envision, we published a technical research roadmap entitled Microbiome Engineering: A Research Roadmap for the Next-Generation Bioeconomy, examining the current state and technical hurdles of microbiome engineering research, outlining future advances that will be needed to continue driving the field forward, and considering the regulatory and social changes that will be needed so these technologies can be deployed in a manner that is safe for people and the environment. The roadmap is the result of a collaborative effort involving over 40 faculty members, industry experts, postdoctoral fellows, and graduate students, and aims to be a resource for both the research community and policymakers interested in advancing the field of microbiome engineering. Microbiome Engineering examines the major scientific and engineering breakthroughs that will be needed to engineer microbiomes and details specific milestones to benchmark progress toward that breakthrough. Community discussions about the future of microbiome engineering research resolved into three main technical themes of the roadmap: Spatiotemporal Control, Functional Biodiversity, and Distributed Metabolism (Figure 1). Spatiotemporal Control considers how the position and function of microbes within a microbiome can be engineered precisely and predictably, both in space and over time. Functional Biodiversity discusses how to engineer functionally similar, but taxonomically diverse, collections of organisms in a microbiome, to maintain stable function across environments. Looking forward, we believe that engineering diversity is of particular importance because it will be critical for applications involving microbiomes outside of the lab, but