December 6, 2025
Journal Article

The Tier System: A Host Development Framework for Bioengineering

Abstract

Development of microorganisms into mature bioproduction host strains has typically been a slow and circuitous process, wherein multiple groups apply disparate approaches with minimal coordination over decades. To help organize and streamline host development efforts, we introduce the Tier System for Host Development, a conceptual model and guide for developing microbial hosts that can ultimately lead to a systematic, standardized, less expensive, and more rapid workflow. The Tier System is made up of three Tiers, each consisting of a unique set of strain development Targets including experimental tools, strain properties, experimental information, and process models. By introducing the Tier System, we hope to improve host development activities through standardization and systematization pertaining to non-traditional chassis organisms.

Published: December 6, 2025

Citation

Yeager C., N.J. Hillson, K. Wozniak, V.K. Mutalik, C.W. Johnson, K.R. Pomraning, and P. Laible, et al. 2025. The Tier System: A Host Development Framework for Bioengineering. Current Opinion in Biotechnology 92:Art. No. 103260. PNNL-SA-203509. doi:10.1016/j.copbio.2025.103260

Research topics