1,3-Propanediol production in a two-step process fermentation from renewable feedstock

Area of Science:

• Biotechnology
• Metabolic Engineering
• Industrial Microbiology

Background:

• 1,3-Propanediol (1,3-PDO) is a valuable chemical intermediate.
• Efficient and sustainable production methods are crucial.
• Biotechnological routes offer an alternative to petrochemical processes.

Purpose of the Study:

• To develop and optimize a two-step bioprocess for 1,3-propanediol production from glucose and molasses.
• To utilize metabolically engineered Saccharomyces cerevisiae and Clostridium acetobutylicum strains.
• To investigate the impact of initial sugar concentration on process performance.

Main Methods:

• A two-step fermentation process was employed in a single bioreactor.
• Engineered Saccharomyces cerevisiae HC42 converted glucose to glycerol.
• Engineered Clostridium acetobutylicum DG1 (pSPD5) converted glycerol to 1,3-propanediol.

Main Results:

• The highest 1,3-propanediol concentration (25.5 g/L) was achieved with an initial glucose concentration of 103 g/L.
• This resulted in a yield of 0.24 g/g sugar and productivity of 0.16 g/L/h.
• Molasses at higher concentrations (>56.2 g/L) led to lower yields due to incomplete glycerol conversion.

Conclusions:

• The developed two-step bioprocess is a flexible and efficient method for 1,3-propanediol production.
• Optimized conditions, particularly initial glucose concentration, are critical for maximizing yield.
• This biotechnological approach offers a sustainable alternative for 1,3-propanediol synthesis.