Continuous fermentation of sugar cane syrup using immobilized yeast cells

Area of Science:

• Biotechnology
• Biomaterials
• Microbial Fermentation

Background:

• Baker's yeast (Saccharomyces sp.) fermentation is crucial for various industries.
• Cell immobilization can improve microbial activity and process efficiency.
• Chrysotile, a fibrous magnesium silicate, offers a potential support material for cell immobilization.

Purpose of the Study:

• To investigate the immobilization of Saccharomyces yeast strains on chrysotile.
• To evaluate the impact of chrysotile immobilization on yeast fermentation performance, especially with high glucose concentrations.
• To assess the feasibility of using immobilized yeast in a continuous packed bed reactor.

Main Methods:

• Immobilization of Saccharomyces sp. and commercial Baker's yeast onto chrysotile.
• Fermentation experiments with varying glucose concentrations (30-50% w/v).
• Setup and operation of a packed bed reactor for continuous fermentation.

Main Results:

• Immobilized yeast exhibited significantly higher activity and fermentation rates (1.2-2.5 times increase) in 30% w/v glucose.
• Yields for immobilized cells ranged from 80.4% to 97.3%, compared to 72.7% to 84.5% for free cells.
• Continuous fermentation in a packed bed reactor achieved productivities of 20-25 g/L/h initially, sustained at 16 g/L/h after 50 days.

Conclusions:

• Chrysotile is an effective support for immobilizing Saccharomyces yeast, enhancing fermentation performance.
• Immobilization on chrysotile improves fermentation efficiency and yields, especially under high substrate loads.
• Continuous fermentation using chrysotile-immobilized yeast is a viable and sustainable bioprocess.