Investigation of Efficient Pullulan Synthesis Utilizing Huangjiu Lees as a Substrate

Area of Science:

• Biotechnology
• Industrial Microbiology
• Biopolymer Production

Background:

• Pullulan, a high-value biopolymer from Aureobasidium pullulans, has diverse applications but faces high production costs.
• Waste Huangjiu lees, a byproduct of the Huangjiu industry, present an environmental challenge and a potential resource.
• Developing cost-effective substrates is crucial for expanding pullulan's industrial use.

Purpose of the Study:

• To investigate the feasibility of using Huangjiu lees as a fermentation substrate for pullulan production.
• To enhance pullulan yield through strain evolution and fermentation optimization.
• To elucidate the molecular mechanisms underlying pullulan biosynthesis using Huangjiu lees.

Main Methods:

• Employing waste Huangjiu lees as a fermentation substrate for Aureobasidium pullulans.
• Utilizing adaptive evolution to develop a high-performance strain (Aureobasidium pullulans AP9).
• Conducting transcriptome analysis to understand the impact of Huangjiu lees on biosynthesis.
• Optimizing fermentation conditions via single-factor analysis and multi-strain staged fermentation.

Main Results:

• An evolved strain, Aureobasidium pullulans AP9, showed improved pullulan production from Huangjiu lees.
• Transcriptome analysis provided insights into pullulan biosynthesis regulation.
• Optimized conditions and a staged fermentation strategy achieved a pullulan yield of 22.06 g/L.
• The produced pullulan had a molecular weight of 1.04 × 10^6 Da.

Conclusions:

• Huangjiu lees are a viable and sustainable substrate for pullulan production.
• Strain evolution and fermentation optimization are effective strategies for enhancing yield.
• This research offers a valuable approach for the resource utilization of Huangjiu industry byproducts.