By leveraging the unique qualities of microorganisms, engineered living materials (ELMs) offer functional and economic advantages in everyday applications along with notable ecological benefits. This study contributes to the growing field of biodesign by examining the potential of Flavobacteria for thermochromic ELMs. Many Flavobacteria, commonly found in marine environments, produce iridescent structural colorations as their colonies expand on semi-solid surfaces through gliding motility. In this study, we analyzed the effects of temperature variations on flavobacterium Cellulophaga lytica PLY-A2, characterizing distinct changes in colony growth and iridescent colorations at a macroscopic and microscopic scale. Using scanning electron microscopy, we investigated the relationship between iridescent color and the underlying cell-based optical structures. By providing insights into the temperature-responsive behavior of Flavobacteria, our findings highlight their potential for future thermochromic ELMs—with applications ranging from sustainable food packaging to smart textiles—while encouraging further characterization studies within biodesign research.

Inspired by biological functions of living systems, researchers have engineered cells as independent functional materials or integrated them within a natural or synthetic matrix to create engineered living materials (ELMs). However, the ‘livingness’ of cells in such materials poses serious drawbacks, such as a short lifespan and the need for cold-chain logistics. Bacterial spores have emerged as a game changer to bypass these shortcomings as a result of their intrinsic dormancy and resistance against harsh conditions. Emerging synthetic biology tools tailored for engineering spores and better understanding of their physical properties have led to novel applications of spore-based materials. Here, we review recent advances in such materials and discuss future challenges for the development of time- and cost-efficient spore-based materials with high performance.