TY - JOUR
T1 - Continuous enzymatic synthesis of lactulose in packed-bed reactor with immobilized Aspergillus oryzae Β-galactosidase
AU - Guerrero, Cecilia
AU - Valdivia, Felipe
AU - Ubilla, Claudia
AU - Ramírez, Nicolás
AU - Gómez, Matías
AU - Aburto, Carla
AU - Vera, Carlos
AU - Illanes, Andrés
N1 - Funding Information:
Work financed by Chilean Fondecyt Grant 1160216. We acknowledge generous donation of β-galactosidase from Enzyme Development Corporation.
Publisher Copyright:
© 2018
PY - 2019/4
Y1 - 2019/4
N2 - Lactulose synthesis from fructose and lactose in continuous packed-bed reactor operation with glyoxyl-agarose immobilized Aspergillus oryzae β-galactosidase is reported for the first time. Alternative strategies to conventional batch synthesis have been scarcely explored for lactulose synthesis. The effect of flow rate, substrates ratio and biocatalyst-inert packing material mass ratio (MB/MIM) were studied on reactor performance. Increase in any of these variables produced an increase in lactulose yield (YLu) being higher than obtained in batch synthesis at comparable conditions. Maximum YLu of 0.6 g·g−1 was obtained at 50 °C, pH 4.5, 50% w/w total sugars, 15 mL·min−1, fructose/lactose molar ratio of 12 and MB/MIM of 1/8 g·g−1; at such conditions yield of transgalactosylated oligosaccharides (YTOS) was 0.16 g·g−1, selectivity (lactulose/TOS molar ratio) was 5.4 and lactose conversion (XLactose) was 28%. Reactor operation with recycle had no significant effect on yield, producing only some decrease in productivity.
AB - Lactulose synthesis from fructose and lactose in continuous packed-bed reactor operation with glyoxyl-agarose immobilized Aspergillus oryzae β-galactosidase is reported for the first time. Alternative strategies to conventional batch synthesis have been scarcely explored for lactulose synthesis. The effect of flow rate, substrates ratio and biocatalyst-inert packing material mass ratio (MB/MIM) were studied on reactor performance. Increase in any of these variables produced an increase in lactulose yield (YLu) being higher than obtained in batch synthesis at comparable conditions. Maximum YLu of 0.6 g·g−1 was obtained at 50 °C, pH 4.5, 50% w/w total sugars, 15 mL·min−1, fructose/lactose molar ratio of 12 and MB/MIM of 1/8 g·g−1; at such conditions yield of transgalactosylated oligosaccharides (YTOS) was 0.16 g·g−1, selectivity (lactulose/TOS molar ratio) was 5.4 and lactose conversion (XLactose) was 28%. Reactor operation with recycle had no significant effect on yield, producing only some decrease in productivity.
KW - Continuous operation
KW - Glyoxyl agarose
KW - Lactulose
KW - Packed-bed reactor
KW - β-Galactosidase
UR - http://www.scopus.com/inward/record.url?scp=85060617326&partnerID=8YFLogxK
U2 - 10.1016/j.biortech.2018.12.018
DO - 10.1016/j.biortech.2018.12.018
M3 - Article
C2 - 30708333
AN - SCOPUS:85060617326
VL - 278
SP - 296
EP - 302
JO - Bioresource Technology
JF - Bioresource Technology
SN - 0960-8524
ER -