BOSTON, February 29, 2024 — Forget everything you think you know about sugar. Scientists at Tufts University have engineered bacteria to produce tagatose, a naturally occurring sugar that tastes remarkably like table sugar but with a fraction of the calories and a potentially gentler impact on your health.
A Sweet Spot: New Biotech Could Deliver Guilt-Free Sugar
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Researchers are one step closer to replicating sugar’s taste without the health drawbacks.
- Tagatose mimics the taste of sugar with roughly 60% fewer calories.
- The FDA has classified tagatose as “generally recognized as safe.”
- Engineered bacteria now produce tagatose with yields as high as 95%, making it more cost-effective.
- Unlike table sugar, tagatose may limit the growth of cavity-causing bacteria and even promote gut health.
For over a century, the quest for a healthy sugar substitute has driven innovation, from saccharin in the 19th century to modern options like stevia and monk fruit. The challenge? Replicating that familiar sweetness without the baggage of excess calories, tooth decay, and increased risks of obesity, insulin resistance, and diabetes. Now, a study published in Cell Reports Physical Science suggests a breakthrough may be within reach.
What Exactly *Is* Tagatose?
Tagatose isn’t some lab-created concoction; it exists naturally, albeit in small amounts. You’ll find it in milk and dairy products when lactose breaks down during processes like yogurt, cheese, and kefir production. Trace amounts also appear in fruits like apples, pineapples, and oranges, but typically make up less than 0.2% of their sugar content. Because of this scarcity, tagatose has historically been manufactured rather than extracted directly from food sources.
Engineering Bacteria for a Sweet Solution
“There are established processes to produce tagatose, but they are inefficient and expensive,” explained Nik Nair, associate professor of chemical and biological engineering at Tufts. To overcome this hurdle, the research team turned to genetic engineering.
“We developed a way to produce tagatose by engineering the bacteria Escherichia coli to work as tiny factories, loaded with the right enzymes to process abundant amounts of glucose into tagatose. This is much more economically feasible than our previous approach, which used less abundant and expensive galactose to make tagatose,” Nair said.
The team modified the bacteria to include a newly discovered enzyme from slime mold called galactose-1-phosphate-selective phosphatase (Gal1P). This enzyme allows the bacteria to generate galactose directly from glucose. Another enzyme, arabinose isomerase, then converts the galactose into tagatose. This process achieves yields as high as 95% – a significant leap from traditional methods, which typically range from 40 to 77%.
Sweetness, Safety, and Beyond
Tagatose delivers approximately 92% of the sweetness of sucrose (table sugar) while containing about 60% fewer calories. Importantly, the FDA has designated it as “generally recognized as safe” – the same classification as common ingredients like salt, vinegar, and baking soda.
Beyond its potential for weight management, tagatose may offer additional health benefits. Unlike sucrose, which fuels bacteria that cause cavities, tagatose appears to limit the growth of these harmful microbes and may even promote healthier bacteria in both the mouth and gut.
A Versatile Sweetener for Cooking and Baking
Because it’s low in calories and poorly absorbed, tagatose functions as a “bulk sweetener,” meaning it can replace sugar not just for sweetness, but also for the physical properties it provides in cooking and baking – something many high-intensity sweeteners can’t replicate. Tagatose browns like sugar when heated and closely matches its flavor and mouthfeel.
“The key innovation in the biosynthesis of tagatose was in finding the slime mold Gal1P enzyme and splicing it into our production bacteria,” Nair explained. “That allowed us to reverse a natural biological pathway that metabolizes galactose to glucose and instead generate galactose from glucose supplied as a feedstock. Tagatose and potentially other rare sugars can be synthesized from that point.”
The researchers believe this approach could pave the way for more efficient production of other rare sugars, potentially revolutionizing the sweetener industry.
