Modeling and Theoretical Analysis of Isomaltooligosaccharide (IMO) Production Using Fed-Batch Process

Abstract

Isomaltooligosaccharide (IMO), a potential prebiotic, has been successfully produced in an enzymatic reaction using α-glucosidase obtained from Aspergillus niger PFS 08 and maltose as a substrate in a batch system (Basu et al. in Catal Sci Technol 5:2945–2958, 2015). The reaction mechanism was modeled using a set of experimental data and later validated against a different experimental data in the same study. In the present study, thus obtained model has been extended to a fed-batch system where in theoretical analysis has been carried out. The model simulations were carried for constant feeding, and linear feeding. Some of the simulations have resulted in higher yields in comparison to the batch experiments. It has been observed that in case of constant feeding, i.e., feeding at a constant flowrate throughout the fed-batch, with flow rate of 0.005 L/h and above value has improved the yield of IMO significantly. The yield of IMO (g IMO/g maltose) for batch experiment was 0.38 at the end of 60 h (Basu et al. in Catal Sci Technol 5:2945–2958, 2015), whereas at flow-rates ≥0.005 L/h the yield of IMO ranged between 0.50 and 0.53 at the end of 60 h. Similarly, in case of linear feeding, where in the feed was a linear function of time, the yields in IMO increased significantly. Here in linear feeding, different incremental slopes, ranging 2 × 10⁻⁵ to 2 × 10⁻¹ L/h² were selected to dose the maltose in separate simulations, and it was observed that the yields of IMO ranged between 0.42 and 0.58 in case of 60 h of fed-batch reaction. Using both constant and linear feeding profiles, simulations were again carried for a time period of 24 h as the yield of IMO in the batch reaction was maximum at the end of 24 h. From these simulation results, the yields observed were greater than 0.6. Finally from this theoretical study it could be concluded that higher yields and productivity can be achieved in the fed-batch process of IMO production in comparison to batch setup.

Appendix

$G$	Glucose	V 4r	Maximum velocity of hydrolysis of isomaltose to glucose (g/L h)
$G_{2}^{{}}$	Maltose	K 4M	Michaelis-Menton constant of hydrolysis of isomaltose to glucose (g/L)
$G_{2}^{'}$	Isomaltose	K 4iG	Competitive inhibition constant by glucose on isomaltose as substrate (g/L)
$G_{3}$	Panose	v 5r	Maximum velocity of hydrolysis of maltotriose to maltose (g/L h)
$G_{3}^{'}$	Maltotriose	K 5M	Michaelis-Menton constant of hydrolysis of maltotriose to maltose (g/L)
$G_{3}^{''}$	Isomaltotriose	K 5iG	Competitive inhibition constant by glucose on maltotriose as substrate (g/L)
$G_{4}$	Maltotetraose	K 5iG2	Competitive inhibition constant bymaltose on maltotriose as substrate (g/L)
$G_{4}^{'}$	Glucosyl-panose	v 6r	Maximum velocity of hydrolysis of maltotetraose to maltotriose (g/L h)
v	Maximum velocity (g/L h)	K 6M	Michaelis-Menton constant of hydrolysis of maltotetraose to maltotriose (g/L)
K M	Michaelis-Menton constant (g/L)	K 6iG	Competitive inhibition constant by glucose on maltotetraose as substrate (g/L)
K i	Inhibition constant (g/L)	v 7r	Maximum velocity of hydrolysis of glucosyl-panose to panose (g/L h)
R	Rate of reaction (1, 2, 3, … subscripts denotes Eqs. 1, 2, 3, …)	K 7M	Michaelis-Menton constant of hydrolysis of glucosyl-panose to panose (g/L)
v 1r	Maximum velocity of hydrolysis of maltose to glucose (g/L h)	K 7iG	Competitive inhibition constant by glucose on glucosyl-panose as substrate (g/L)
K 1M	Michaelis-Menton constant of hydrolysis of maltose to glucose (g/L)	v 8r	Maximum velocity of hydrolysis of isomaltotriose to isomaltose (g/L h)
K 1iG2	Substrate inhibition constant of hydrolysis of maltose to glucose (g/L)	K 8M	Michaelis-Menton constant of hydrolysis of isomaltotriose to isomaltose (g/L)
v 2r	Maximum velocity of hydrolysis of panose to isomaltose (g/L h)	v 9r	Maximum velocity of transglucosylation of maltose to maltotriose (g/L h)
K 2M	Michaelis-Menton constant of hydrolysis of panose to isomaltose (g/L)	K 9M	Michaelis-Menton constant of transglucosylation of maltose to maltotriose (g/L)
v 3r	Maximum velocity of hydrolysis of panose to maltose (g/L h)	K 9iG2	Substrate inhibition constant of transglucosylation of maltose to maltotriose (g/L)
K 3M	Michaelis-Menton constant of hydrolysis of panose to maltose (g/L)	v 10r	Maximum velocity of transglucosylation of maltose to panose (g/L h)
K 3iG	Competitive inhibition constant by glucose on panose as substrate (g/L)	K 10M	Michaelis-Menton constant of transglucosylation of maltose to panose (g/L)
K 3iG2	Competitive inhibition constant by maltose on panose as substrate (g/L)	K 10iG2	Substrate inhibition constant of transglucosylation of maltose to panose (g/L)
v 11r	Maximum velocity of transglucosylation of isomaltose to isomaltotriose (g/L h)	K 13M	Michaelis-Menton constant of transglucosylation of panose to glucosyl-panose (g/L)
K 11M	Michaelis-Menton constant of transglucosylation of isomaltose to isomaltotriose (g/L)	K 13iG2	Competitive inhibition constant by maltose on panose as substrate (g/L)
K 11iG	Substrate inhibition constant of transglucosylation of isomaltose to isomaltotriose (g/L)	v 14r	maximum velocity of transglucosylation of glucose to isomaltose (g/L h)
v 12r	Maximum velocity of transglucosylation of maltotriose to maltotetraose (g/L h)	K 14M	Michaelis-Menton constant of transglucosylation of glucose to isomaltose (g/L)
K 12M	Michaelis-Menton constant of transglucosylation of maltotriose to maltotetraose (g/L)
K 12iG2	Substrate inhibition constant of transglucosylation of maltotriose to maltotetraose (g/L)
v 13r	Maximum velocity of transglucosylation of panose to glucosyl-panose (g/L h)