High yield production of 3-hydroxypropionic acid using Issatchenkia orientalis

Area of Science:

• Biotechnology
• Metabolic Engineering
• Industrial Microbiology

Background:

• Biomanufacturing offers a sustainable alternative to traditional chemical production.
• 3-Hydroxypropionic acid (3HP) is a high-value chemical and precursor for bioplastics, but cost-effective microbial production is challenging.
• Issatchenkia orientalis is an acid-tolerant yeast with potential for low-pH bioprocesses.

Purpose of the Study:

• To establish Issatchenkia orientalis as a robust host for low-pH 3-Hydroxypropionic acid (3HP) biosynthesis.
• To identify and optimize metabolic pathways for efficient 3HP production.
• To assess the economic viability of 3HP production using this engineered yeast.

Main Methods:

• Genome-scale modeling to identify optimal biosynthetic pathways (β-alanine pathway).
• Sequence similarity network analysis to discover highly active enzymes (PAND, BAPAT, YDFG).
• Metabolic engineering strategies including gene integration, gene knockouts, and gene overexpression.
• Fed-batch fermentation using low-cost media (corn steep liquor) at controlled pH.

Main Results:

• The β-alanine pathway was identified as optimal for 3HP production.
• Engineered I. orientalis achieved a titer of 29 g/L in shake flasks and 92 g/L in fed-batch fermentation.
• High yield (0.7 g/g) and productivity (0.55 g/L/h) were obtained at pH 4.
• Techno-economic analysis suggests potential for financially viable acrylic acid production.

Conclusions:

• Issatchenkia orientalis is a promising platform for cost-effective 3HP production.
• Optimized metabolic engineering and fermentation conditions significantly enhance 3HP production.
• This work supports the industrial commercialization of sustainable bioplastics precursors.