Production of poly(malic acid) from sugarcane juice in fermentation by Aureobasidium pullulans: Kinetics and process...

Area of Science:

• Biotechnology
• Polymer Science
• Industrial Microbiology

Background:

• Poly(β-l-malic acid) (PMA) is a biodegradable polymer with significant biomedical potential.
• PMA hydrolyzes to malic acid (MA), a common acidulant in food and pharmaceuticals.
• Developing economical production methods for PMA is crucial for its industrial application.

Purpose of the Study:

• To investigate the production of poly(β-l-malic acid) (PMA) from sucrose and sugarcane juice using Aureobasidium pullulans ZX-10.
• To evaluate sugarcane juice as a cost-effective and readily available substrate for PMA fermentation.
• To optimize fermentation conditions for high PMA titer, yield, and productivity.

Main Methods:

• Fermentation studies were conducted in shake-flasks and bioreactors using Aureobasidium pullulans ZX-10.
• Fed-batch and repeated-batch fermentation strategies with cell recycle were employed.
• Process economic analysis was performed to determine production cost.

Main Results:

• Sugarcane juice served as an effective substrate for PMA production without pretreatment or nutrient supplementation.
• A high PMA titer of 116.3 g/L and a yield of 0.41 g/g were achieved in fed-batch fermentation.
• A productivity of 0.66 g/L·h was obtained in repeated-batch fermentation with cell recycle, outperforming other feedstocks.

Conclusions:

• Sugarcane juice is a viable and economical feedstock for poly(β-l-malic acid) production.
• Optimized fermentation processes can achieve industrially relevant titers and productivities.
• The estimated production cost of $1.33/kg makes bio-based PMA cost-competitive for various applications.