Trienzymatic Complex System for Isomerization of Agar-Derived d -Galactose into d -Tagatose as a Low-Calorie Sweetener

Da Woon Jeong, Jeong Eun Hyeon, Sang Kyu Shin, Sung Ok Han

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)


d-Tagatose is a rare monosaccharide that is used in products in the food industry as a low-calorie sweetener. To facilitate biological conversion of d-tagatose, the agarolytic enzyme complexes based on the principle of the cellulosome structure were constructed through dockerin-cohesin interaction with the scaffoldin. The construction of agarolytic complexes composed of l-arabinose isomerase caused efficient isomerization activity on the agar-derived sugars. In a trienzymatic complex, the chimeric β-agarase (cAgaB) and anhydro-galactosidase (cAhgA) from Zobellia galactanivorans could synergistically hydrolyze natural agar substrates and l-arabinose isomerase (LsAraA Doc) from Lactobacillus sakei 23K could convert d-galactose into d-tagatose. The trienzymatic complex increased the concentration of d-tagatose from the agar substrate to 4.2 g/L. Compared with the monomeric enzyme, the multimeric enzyme showed a 1.4-fold increase in tagatose production, good thermostability, and reusability. A residual activity of 75% remained, and 52% of conversion was noted after five recycles. These results indicated that the dockerin-fused chimeric enzymes on the scaffoldin successfully isomerized d-galactose into d-tagatose with synergistic activity. Thus, the results demonstrated the possibility of advancing efficient strategies for utilizing red algae as a biomass source to produce d-tagatose in the industrial food field that uses marine biomass as the feedstock.

Original languageEnglish
Pages (from-to)3195-3202
Number of pages8
JournalJournal of agricultural and food chemistry
Issue number10
Publication statusPublished - 2020 Mar 11


  • agarolytic complex
  • d -tagatose
  • l -arabinose isomerase
  • red algae

ASJC Scopus subject areas

  • Chemistry(all)
  • Agricultural and Biological Sciences(all)


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