Advanced strategies for production of soy-processing enzyme

Area of Science:

• Biotechnology
• Enzyme Engineering
• Industrial Microbiology

Background:

• Enzyme production for biorefineries is crucial but expensive.
• Achieving high titers and specific enzyme combinations in single fermentations is challenging.
• Soybean carbohydrate hydrolysis requires multiple enzyme activities.

Purpose of the Study:

• To enhance the productivity and composition of multiple enzyme activities for soybean carbohydrate hydrolysis in a single fermentation.
• To evaluate fed-batch substrate addition and programmed pH-decrease rates.
• To optimize enzyme production using *Aspergillus niger*.

Main Methods:

• Utilized a selected *Aspergillus niger* strain known for high carbohydrase and low protease production.
• Investigated fed-batch soybean hull (SH) addition strategies.
• Optimized programmed pH-decrease rates during fermentation.

Main Results:

• Fed-batch SH addition did not significantly improve pectinase and cellulase production and reduced α-galactosidase levels compared to batch fermentation.
• Optimized pH decrease from 7 to 4 over 84 hours (0.0357/h) yielded the highest enzyme activities.
• Achieved peak pectinase (19.1 U/mL), α-galactosidase (15.7 U/mL), and cellulase (0.88 FPU/mL).

Conclusions:

• Programmed pH decrease is an effective strategy for producing complex enzyme mixtures.
• Optimized enzyme production improves the efficiency and economics of enzymatic soy processing.
• Enzymatic hydrolysis of soybean meal carbohydrates yields high-value protein products and fermentation feedstock.