Construction of an Ultra-Thermostable D-Allulose 3-Epimerase from Arthrobacter globiformis M30

If you formulate reduced-sugar foods, enzyme performance sits right at the center of your cost model. D-allulose production depends on that. A new paper in FEBS Open Bio describes a chimeric mutant of the enzyme AgDAE from Arthrobacter globiformis M30, and it handles heat far better than the wild-type.

Why the enzyme matters

D-allulose is a rare sugar that brings sweetness and bulk with fewer calories than sucrose. The bottleneck is conversion. AgDAE, a D-allulose 3-epimerase, converts D-fructose into D-allulose. Matsutani Chemical Industrial already took this enzyme and built a scaled production system. They sell it under the Astraea brand.

So the basic enzyme works commercially. The question is whether it works hard enough.

What the study did

Researchers used protein engineering to build a chimeric mutant E. They took the AgDAE enzyme and recombined parts of it into a new construct. Then they measured activity and stability.

The results point in one direction: heat tolerance.

Key findings

Mutant E stays highly functional above 95°C. That’s hot. It also remains stable below 80°C. That distinction matters. You can store it or handle it without constant cold-chain worry, and you can run the reaction at high temperature.

Here is the comparison from the paper:

Property	Wild-type AgDAE	Mutant E
Highly functional above 95°C	Not reported	Yes
Stable below 80°C	Not reported	Yes
kcat on D-fructose	Baseline	>2× wild-type
Catalytic efficiency (kcat/Km)	Baseline	Improved

The kcat number is the one to circle. A kcat more than twice the wild-type means the mutant enzyme converts substrate faster. Faster conversion, all else equal, means less enzyme, shorter residence time, or higher throughput in a continuous system.

What it means for manufacturers

This is not just a lab curiosity. The parent enzyme already runs in a commercial D-allulose process. Astraea exists. So the new mutant is an incremental improvement on something that already works.

Heat tolerance is the practical prize. Running an isomerization reaction above 95°C gives process engineers much more room to design efficient operations. The two-fold kcat increase is another lever. You can use less enzyme per batch. That lowers enzyme cost, or it lets you shorten hold times.

There are still steps before market. The study reports enzyme performance, not food-grade production data. A supplier must validate mutant E under industrial conditions and confirm it meets regulatory standards. But the direction is clear.

FAQ

Is mutant E commercially available? The paper does not say that. Matsutani Chemical Industrial commercialized the wild-type-based process under the Astraea brand. Mutant E is a research result at this stage.

What does AgDAE do? AgDAE is a D-allulose 3-epimerase from Arthrobacter globiformis M30. It converts D-fructose into D-allulose.

Why is heat tolerance such a big deal in allulose production? High reaction temperatures improve solubility and cut contamination risk. If an enzyme works above 95°C and stays stable below 80°C, formulators get a wider processing window.

A number to remember

Remember 95°C. That’s where the mutant enzyme still works. For anyone producing or buying D-allulose, an enzyme that can operate at that temperature changes the engineering picture. The commercial Astraea process already proves the enzyme class. Mutant E simply raises the ceiling.