Mixture design as first step for improved glutaminase production in solid-state fermentation by isolated Bacillus

Area of Science:

• Biotechnology
• Enzyme Production
• Microbial Fermentation

Background:

• Glutaminase is an enzyme with various industrial applications.
• Optimizing microbial enzyme production often involves exploring different substrate compositions.
• Bacillus species are known producers of valuable enzymes like glutaminase.

Purpose of the Study:

• To investigate the impact of substrate mixture design on glutaminase production by isolated Bacillus sp.
• To identify optimal substrate combinations for maximizing glutaminase yield.
• To assess the potential for large-scale glutaminase production using optimized solid-state fermentation.

Main Methods:

• Utilized an augmented simplex centroid design to study a three-component mixture of wheat bran, Bengal gram husk, and palm seed fibre.
• Evaluated the glutaminase production of Bacillus sp. using individual and combined substrates.
• Quantified enzyme production in units per gram of dry substrate (U gds(-1)).

Main Results:

• Bengal gram husk alone yielded 2789 U gds(-1) of glutaminase.
• A two-level combination of wheat bran and Bengal gram husk achieved a maximum production of 3300 U gds(-1).
• The optimal ratio for maximum glutaminase production was identified as 66:34 for Bengal gram husk to wheat bran.

Conclusions:

• Bengal gram husk is the most suitable single substrate for glutaminase production by Bacillus sp.
• Mixture optimization, specifically a two-level combination of Bengal gram husk and wheat bran, significantly enhances glutaminase yield.
• The findings support the use of multi-substrate mixtures over single substrates for cost-effective, large-scale commercial glutaminase production.