A new system of Erwinia sp. D12 cells immobilized in a matrix of alginate and algaroba gum (Prosopis juliflora): An efficient way to improve isomaltulose production

Abstract

Isomaltulose is a non-cariogenic sugar widely used in sweets and soft drinks that can be obtained from sucrose via enzymatic reactions catalyzed by microbial glucosyltransferases. In this study, an efficient novel system composed of algaroba gum, cashew gum, and alginate was used on the immobilization of Erwinia sp. D12 aiming improve its capability for conversion of sucrose into isomaltulose. The microbial growth of Erwinia sp. D12 cells was carried out in a bioreactor for obtaining the cell mass of microorganisms. The beads containing the microorganisms were characterized by diameter size, encapsulation efficiency, and FTIR spectroscopy; isomaltulose quantification was performed by high-performance liquid chromatography. The system composed of algaroba gum (1.5 % w/v) and alginate (1.5 % w/v) possessed the highest encapsulation efficiency (91.81 %) of immobilized cells and high isomaltulose production (323.38 g/L) at 12 h of reaction. Additionally, the stability of the immobilized cells was kept until 72 h of continuous reaction resulting in an isomaltulose production of 167.52 g/L; demonstrating that up to 50 % of alginate can be replaced by incorporating algaroba gum. The combination of algaroba gum and alginate is promising and recommended when immobilizing Erwinia sp. D12 cells, as results showed an increase in conversion of sucrose into isomaltulose.