Researchers report a method to produce the rare sugar tagatose by engineering Escherichia coli. Tagatose occurs naturally only in trace amounts — often less than 0.2% of sugars in natural sources — so it is usually made rather than extracted from foods such as milk and some fruits.
The Tufts team inserted a slime mold enzyme, galactose‑1‑phosphate‑selective phosphatase (Gal1P), and expressed arabinose isomerase in the bacteria. Gal1P helps form galactose directly from glucose, and arabinose isomerase converts that galactose into tagatose. The researchers say this approach is more economical than older methods that relied on galactose feedstock, and it gives much higher conversion yields than conventional manufacturing.
Tagatose is about as sweet as sucrose but has far fewer calories. The FDA has designated it "generally recognized as safe," and clinical studies report very small increases in plasma glucose or insulin after ingestion. Evidence also suggests benefits for oral and gut bacteria and it can be used as a bulk sweetener in recipes.
Difficult words
- tagatose — a rare sugar used as a low-calorie sweetener
- enzyme — a protein that speeds up chemical reactions
- phosphatase — an enzyme that removes phosphate groups from molecules
- feedstock — raw material used to make a product in industry
- yield — the amount of product made from a processyields
- economical — costing less money or saving resources
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Discussion questions
- Would you try recipes that use tagatose as a sweetener? Why or why not?
- How might lower-calorie sugars like tagatose affect your eating or cooking habits?
- What benefits or concerns do you see about producing food ingredients using engineered bacteria?
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