Abstract
Biotechnological production of high value chemical products increasingly involves engineering in vivo multi-enzyme pathways and host metabolism. Recent approaches to these engineering objectives have made use of molecular tools to advance de novo pathway identification, tunable enzyme expression, and rapid pathway construction. Molecular tools also enable optimization of single enzymes and entire genomes through diversity generation and screening, whole cell analytics, and synthetic metabolic control networks. In this review, we focus on advanced molecular tools and their applications to engineered pathways in host organisms, highlighting the degree to which each tool is generalizable.