Sweet As Sugar-Efficient Conversion of Lactose into Sweet Sugars Using a Novel Whole-Cell Catalyst

Jing Shen, Jun Chen, Peter Ruhdal Jensen*, Christian Solem

*Corresponding author for this work

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Lactose, the sugar contained in milk, has a low sweetness. We have constructed an efficient whole-cell catalyst (WCC) that can be grown on dairy waste and that is able to convert lactose into a mixture of sugars as sweet as sucrose. The WCC is based on Corynebacterium glutamicum ATCC13032, which has been engineered to metabolize lactose, to express xylose and arabinose isomerase, and to eliminate byproduct formation. When introduced in concentrated cheese whey permeate, its content of 98 g/L lactose was completely hydrolyzed and the liberated sugars partially isomerized into 23.5 g/L fructose and 20.4 g/L tagatose, which corresponds to a 49% conversion of the glucose and a 44% conversion of galactose. The latter is similar to what can be obtained using purified enzymes. The new technology enables better resource utilization and allows for dairy waste to be converted into a valuable food sweetener with many potential uses.
Original languageEnglish
JournalJournal of Agricultural and Food Chemistry
Issue number22
Pages (from-to)6257-6262
Publication statusPublished - 2019


  • whole-cell catalyst
  • Corynebacterium glutamicum
  • lactose hydrolysis
  • sugar isomerization
  • sweetener

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