Kinetics and design relation for enzymatic conversion of lactose into galacto-oligosaccharides using commercial grade β-galactosidase.
The enzymatic synthesis of galacto-oligosaccharides (GOS) from lactose was studied using commercial grade β-galactosidase (Biolacta FN5) from Bacillus circulans. The reaction was carried out under free enzyme condition varying initial lactose concentration (ILC: 55-525 g/L), enzyme concentration (0.05-1.575 g/L), temperature (30-50°C) and pH (5.0-6.0). Reaction mixture compositions were analyzed utilizing high performance liquid chromatography (HPLC). A maximum GOS formation of 39% (dry basis) was achieved at an ILC of 525 g/L converting 60% of the lactose fed. Tri-saccharides were the major types of GOS formed, accounting approximately 24%; whereas, tetra-saccharides and penta-saccharides account approximately 12% and 3%, respectively. Design correlation was developed in order to observe the quantitative effect of operating parameters on GOS yield. Further, based on Michaelis-Menten model, four-step reaction pathways were considered for simplistic understanding of the kinetics. Apart from predicting the reaction mixture composition, the approach also provided kinetic parameters though simulation using COPASI 4.7®. Excellent agreements were observed between simulated and experimental results.
Department of Chemical Engineering, Indian Institute of Technology Kanpur, Kanpur 208016, India.
Tapas
T
Palai
Shubhrajyoti
S
Mitra
Prashant K
PK
Bhattacharya
D001407:Bacillus / Q000201:enzymology* / Q000378:metabolism; D005690:Galactose / Q000737:chemistry / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007218:Industrial Microbiology / Q000191:economics; D007700:Kinetics; D007785:Lactose / Q000737:chemistry / Q000378:metabolism*; D009844:Oligosaccharides / Q000138:chemical synthesis* / Q000737:chemistry; D013696:Temperature; D001616:beta-Galactosidase / Q000737:chemistry / Q000378:metabolism*
D009844:Oligosaccharides; D001616:beta-Galactosidase; D007785:Lactose; D005690:Galactose