Updated June 30, 2021:
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Why the research is important to ND soybean farmers
Soybean is high in protein and starch that are; respectively, consist of peptide and glucose as their building block. Although, smaller units like glucose and peptides are fermentable to value added biochemicals like ethanol, ammonia, and lactic acid, the protein and starch need to be broken down first. One of the most viable way to breakdown protein and starch is using enzyme. However, the high cost of enzyme is an economic challenge for the industries. Enzymatic processing can be economical if enzymes are recovered and reused. The development of economic technology to convert soybean to fermentable units will open up new uses and demand for soybeans which will in turn increase farmer income.
Research conducted
The major aim of this research is to produce attached enzymes on magnetic nanoparticles and/or polymer support for processing soybean products including dehulled, fat flake, defatted flake, and soy meal. Similar to what happens in our body during food digestion, soybean starch was broken down into simple glucose by two enzymes including amylase (AMY) and amyloglucosidase (AMG) while soybean protein was broken down to peptide and amino acid by enzyme pepsin. Tow addition modes: stepwise (one after the other) and simultaneous were investigated. The enzymes were then attached to flexible polymer which were then attached to magnetic nanoparticles to make non-magnetic and magnetic nanobiocatalysts.
Final findings of the research
Soybean samples were broken down differently and simultaneous AMG and AMY addition yielded more glucose in all samples, except in defatted flakes. Processing was optimum at 3h for all samples. Attaching flexible support to enzyme provided a joint enzyme action making the attached enzymes performed higher when compared to unattached enzymes. However, AMY-AMG magnetic unit performed lower than free enzyme. Similarly, the samples were broken down protein digesting enzyme called pepsin. Results show that pepsin free enzymes have higher amino acid contents in all samples except in dehulled sample than attached pepsin.
Benefits/Recommendations to North Dakota soybean farmers and industry
The non-magnetic nanobiocatalysts of AMG and AMY are viable for soybean processing to produce fermentable units to ethanol and organic ammonia. Future research work will focus on recoverability of the nanobiocatalysts and production of organic ammonia and ethanol using soybean hydrolysates as sole substrate during fermentation.