Scientists have used bacteria to derive a sugar from fruits and dairy products that has only 38 per cent of the calories of traditional table sugar.The sugar called tagatose is approved by the US Food and Drugs Agency (FDA) as a food additive, and there have been no reports to date of the problems that many sugar substitutes have, such as a metallic taste, or links to cancer, according to the researchers at Tufts University in the US.The researchers said tagatose may be safe for diabetics, and will not cause tooth cavities.While derived from fruits and dairy products, tagatose is not abundant and is difficult to extract from those sources, they said. The manufacturing process involves a conversion from more easily obtained galactose to tagatose and is highly inefficient, with yields that may reach only 30 per cent, the researchers explained.In the study published in the journal Nature Communications, the researchers described a process that may unlock the commercial potential of this low-calorie, low-glycemic sugar.
Assistant Professor Nikhil Nair and postdoctoral fellow Josef Bober, both from the Tufts University, came up with an innovative way to produce the sugar using bacteria as tiny bioreactors that encapsulate the enzymes and reactants.Using this approach, they achieved yields up to 85 per cent. Although there are many steps from the lab to commercial production, yields this high could lead to large-scale manufacturing and getting tagatose on every supermarket shelf, the researchers said.The enzyme of choice to make tagatose from galactose is called L-arabinose isomerase (LAI).However, galactose is not the main target for the enzyme, so the rates and yields of the reaction with galactose are less than optimal.
