On behalf of the Program Chairs, Organizing Committee, and Society for Industrial Microbiology and Biotechnology staff, welcome to the 39th Symposium on Biotechnology for Fuels and Chemicals! Thank you for joining us as we reconvene this annual international meeting back in San Francisco with colleagues new and old from around the globe. As this meeting has evolved and expanded along with the emerging bioeconomy, its focus has also been shifting ever more to new bio-based chemicals, bioproducts, and advanced biofuels. There has never been a more exciting and important time to be working in renewables. Advanced routes to ethanol are no longer a primary focus at this meeting, with direct petroleum replacement technology for biobased products and biofuels making rapid progress. New techniques and automation in synthetic biology and metabolic pathway engineering are greatly expanding the bioproducts portfolio and opening up new processing methodologies for generating and upgrading a variety of renewable feedstock-based process intermediates, for example mixed sugar- and lignin-based feed streams. Enzyme engineering and discovery efforts have expanded well beyond amylases and cellulases into lignin-modification, hemicellulases, and lytic polysaccharide mono-oxygenases, opening up carbon conversion potential well beyond traditional starch and cellulosic feedstocks. Of course, all of these advances still need to be integrated into economical processes that achieve targeted environmental and efficiency benefits, and process scale up and demonstration for bio-based products is also an area where tremendous progress is being made. Please join us for a few days in San Francisco to meet new friends, reconnect with old colleagues, and learn about the latest scientific discoveries and technical advances being made to bolster expanded economic production of bio-based chemicals, products and fuels as we continue to build a more sustainable and prosperous global bioeconomy.