Feasibility of synthesizing γ-[Glu](n ≥ 1)-Gln using high solid concentrations and glutaminase from Bacillus amyloliquefaciens as the catalyst

作者：Tang, Runmei; Sun-Waterhouse, Dongxiao; Xiong, Jian; Cui, Chun^*; Wang, Wei

来源：Food Chemistry, 2020, 310: 125920.

DOI：10.1016/j.foodchem.2019.125920

• High solid concentration
• gamma-[Glu]((n >= 1))-Gln
• Glutaminase
• Enzymatic synthesis

Effects of using high solid concentrations on the synthesis of gamma-[Glu]((n >= 1))-Gln catalyzed by glutaminase from Bacillus amyloliquefaciens were examined in this study. An increment in solid concentration from 10% to 50% (w/w) increased the extent of synthesis of gamma-[Glu]((n >= 1))-Gln, based on the analyses of amino acid composition and amino nitrogen content. Size-exclusion high-performance liquid chromatography analysis revealed an increase in molecular mass of gamma-[Glu]((n >= 1))-Gln resulting from the increase of solid concentration from 10% to 50% (w/ w). UPLC Q TOF MS/MS analysis showed that the enzymatic reaction mixtures post gamma-glutamyl transpeptidation contained gamma-Glu-Gln, gamma-Glu-Glu-Gln, gamma-Glu-Glu-Glu-Gln, gamma-Glu-Glu-Glu-Glu-Gln and gamma-Glu-Glu-Glu-Glu-Glu-Gln. The intensity of each gamma-[Glu]((n=1,2,3,4,5))-Gln produced at a solid concentration of 50% (w/w) was higher than that at 10% (w/w). These findings indicated the potential of such an energy- and water-efficient approach for synthesizing gamma-[Glu](n >= 1)-Gln at high solid concentrations.