Converting Industrial Byproduct Crude Glycerol to 3-Hydroxypropionic Acid with Bioengineered Acid-Resilient Yeast I. orientalis

3-hydroxypropionic acid (3-HP) is a commercially significant platform chemical that has a high industrial value in environmentally friendly products. Here, we demostrate the bio-base synthesis of 3-HP by utilizing crude glycerol—a by-product of biodiesel production—as substrate. Issatchenkia orientalis, a non-conventional acid-tolerant yeast, was engineered using CRISPR-Cas9 genome editing to introduce the 3-HP producing β-alanine pathway for efficient glycerol utilization. Comparative analyses demonstrated that I. orientalis exhibits superior glycerol metabolism capabilities compared to Saccharomyces cerevisiae, maintaining high consumption rates even at elevated glycerol concentrations. Although overexpression of glycerol uptake genes showed limited improvement, pathway-specific genetic modifications significantly enhanced the bioconversion efficiency

This study highlights the feasibility of non-conventional yeast fermentation using metabolic engineering techniques to achieve economically viable and environmentally friendly 3-HP production processes.