To decarbonize the chemical industry and establish a sustainable circular carbon economy, transitioning from petroleum-based to renewable carbon sources like plant biomass is crucial.  Microbial fermentation technology can seamlessly integrate into existing industry infrastructure, converting biomass into diverse chemical building blocks. By engineering microbial metabolic networks, these cells can function as tiny factories producing a wide range of chemicals. Achieving commercially viable productivity in these cell factories remains a significant challenge, often due to imbalances in the metabolic pathway and unintended interactions between the engineered pathway and the host cell's native metabolism. For example, pathway intermediate metabolites might be toxic to the host and lost through competing endogenous reactions or secretion. In this dissertation, we developed synthetic condensates as a platform to localize engineered biosynthetic pathways, enhancing flux toward the desired product by minimizing unwanted interactions with the host's native metabolism. In Chapter 1, I present an overview of the field of metabolic engineering, along with strategies for localizing metabolic pathways both found in nature and engineered inspired by nature. In Chapter 2 and 3, we developed a modular and easy-to-adapt synthetic condensate platform and applied it to improve the production of monoterpenes, a class of valuable chemicals, in Saccharomyces cerevisiae. In Chapter 4, we studied the underlying physical principles governing the molecular interactions between condensates and applied this knowledge to engineer multiple immiscible synthetic condensate structures to co-exist in yeast.  Finally in Chapter 5, I discussed how these diverse synthetic condensate platforms can be functionalized to work in tandem with each other to regulate metabolic fluxes. Together, these studies contribute new tools and knowledge for the economically viable production of monoterpenes and other chemicals from microbial fermentation.