Stepwise bioprocess for exopolysaccharide production using potato starch as carbon source

Area of Science:

• Biotechnology
• Microbial Biopolymer Production

Background:

• Xanthan gum is a valuable microbial polysaccharide with diverse industrial applications.
• Current production methods often face limitations in efficiency and yield.
• Optimizing bioprocesses is crucial for cost-effective xanthan gum biosynthesis.

Purpose of the Study:

• To develop an enhanced stepwise bioprocess for xanthan gum production from potato starch.
• To investigate the efficacy of pre-hydrolysis of potato starch for improved microbial substrate utilization.
• To optimize carbon and nitrogen sources for maximizing xanthan gum yield.

Main Methods:

• Potato starch was hydrolyzed by Bacillus sp. to release reducing sugars.
• The hydrolyzed starch was used as a carbon source for xanthan gum biosynthesis by Xanthomonas sp. XC6.
• Yeast extract was evaluated as a nitrogen source for optimal microbial growth and polysaccharide production.

Main Results:

• Bacillus sp. released 30.2 g/L of reducing sugars from potato starch, significantly higher than Xanthomonas sp. XC6 alone (14.5 g/L).
• Xanthan gum production reached 10.0 g/L when yeast extract was used as the nitrogen source.
• The optimized stepwise bioprocess, including downstream processing, achieved a final xanthan gum yield of 17.4 g/L, a 2.8-fold increase over a single-step process.

Conclusions:

• A stepwise bioprocess involving Bacillus sp. pre-hydrolysis of potato starch enhances substrate availability for xanthan gum production.
• This optimized bioprocess significantly increases xanthan gum yield compared to conventional single-step methods.
• The findings offer a promising strategy for more efficient and scalable microbial production of xanthan gum.