Production of D-tagatose, a functional sweetener, utilizing alginate immobilized Lactobacillus fermentum CGMCC2921 cells.
D-tagatose is a ketohexose that can be used as a novel functional sweetener in foods, beverages, and dietary supplements. This study was aimed at developing a high-yielding D-tagatose production process using alginate immobilized Lactobacillus fermentum CGMCC2921 cells. For the isomerization from D-galactose into D-tagatose, the immobilized cells showed optimum temperature and pH at 65 °C and 6.5, respectively. The alginate beads exhibited a good stability after glutaraldehyde treatment and retained 90% of the enzyme activity after eight cycles (192 h at 65 °C) of batch conversion. The addition of borate with a molar ratio of 1.0 to D-galactose led to a significant enhancement in the D-tagatose yield. Using commercial β-galactosidase and immobilized L. fermentum cells, D-tagatose was successfully obtained from lactose after a two-step biotransformation. The relatively high conversion rate and productivity from D-galactose to D-tagatose of 60% and 11.1 g l⁻¹ h⁻¹ were achieved in a packed-bed bioreactor. Moreover, lactobacilli have been approved as generally recognized as safe organisms, which makes this L. fermentum strain an attracting substitute for recombinant Escherichia coli cells among D-tagatose production progresses.
State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing, 210009, People's Republic of China.
Zheng
Z
Xu
Sha
S
Li
Fenggen
F
Fu
Guixiang
G
Li
Xiaohai
X
Feng
Hong
H
Xu
Pingkai
P
Ouyang
D019747:Aldose-Ketose Isomerases / Q000378:metabolism*; D000464:Alginates / Q000737:chemistry; D019149:Bioreactors; D001711:Biotransformation; D018914:Cells, Immobilized; D005516:Food Microbiology; D005690:Galactose / Q000378:metabolism*; D020723:Glucuronic Acid / Q000737:chemistry; D006601:Hexoses / Q000096:biosynthesis*; D006603:Hexuronic Acids / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D052197:Limosilactobacillus fermentum / Q000737:chemistry / Q000201:enzymology*; D013549:Sweetening Agents / Q000378:metabolism*; D013696:Temperature; D001616:beta-Galactosidase / Q000378:metabolism*
D000464:Alginates; D006601:Hexoses; D006603:Hexuronic Acids; D013549:Sweetening Agents; D020723:Glucuronic Acid; D001616:beta-Galactosidase; D019747:Aldose-Ketose Isomerases; C030192:tagatose; D005690:Galactose