Immobilization of Serratia plymuthica by ionic gelation and cross-linking with transglutaminase for the conversion of sucrose into isomaltulose

A Critical Review on Immobilized Sucrose Isomerase and Cells for Producing Isomaltulose

Isomaltulose is a novel sweetener and is considered healthier than the common sugars, such as sucrose or glucose. It has been internationally recognized as a safe food product and holds vast potential in pharmaceutical and food industries. Sucrose isomerase is commonly used to produce isomaltulose from the substrate sucrose in vitro and in vivo. However, free cells/enzymes were often mixed with the product, making recycling difficult and leading to a significant increase in production costs. Immobilized cells/enzymes have the following advantages including easy separation from products, high stability, and reusability, which can significantly reduce production costs. They are more suitable than free ones for industrial production. Recently, immobilized cells/enzymes have been encapsulated using composite materials to enhance their mechanical strength and reusability and reduce leakage. This review summarizes the advancements made in immobilized cells/enzymes for isomaltulose production in terms of refining traditional approaches and innovating in materials and methods. Moreover, innovations in immobilized enzyme methods include cross-linked enzyme aggregates, nanoflowers, inclusion bodies, and directed affinity immobilization. Material innovations involve nanomaterials, graphene oxide, and so on. These innovations circumvent challenges like the utilization of toxic cross-linking agents and enzyme leakage encountered in traditional methods, thus contributing to enhanced enzyme stability.

Adsorption of azo dye by biomass and immobilized Yarrowia lipolytica; equilibrium, kinetic and thermodynamic studies

One of the major environmental problems we have today is dye pollution, primarily caused by the textile industry. This pollution has detrimental effects on aquatic life, soil fertility, and human health. Many microbial biosorbents have been documented in the literature for the removal of a wide range of azo dyes commonly employed in the textile industry. However, Yarrowia lipolytica NBRC1658 is firstly used as both free and immobilized sorbents for the removal of Reactive yellow 18 (RY18), acid red 18 (AR18) and basic blue 41 (BB41) in this study. The effect of experimental conditions such as pH, biosorbent quantity, dye concentration, contact time, and temperature on dye removal capacity are examined. The research findings demonstrate that the adsorption capacity is higher in biomass compared to immobilized cells. The highest adsorption capacities are observed at pH 2 for RY18 and AR18, while pH 9 is optimal for BB41. Increasing the adsorbent dosage and initial concentration significantly improves the adsorption capacity. The Langmuir model best describes the adsorption process, indicating that the dye attaches to the biosorbent in a single layer, with a uniform biosorbent surface. The removal of the dye occurs through a chemical process on the biosorbent surface, as evidenced by the pseudo-second-order kinetic model. According to thermodynamic analysis, higher temperatures promote greater adsorption of dyes. Our study shows the effectiveness of Yarrowia lipolyica NBRC1658 as a biosorbent in the removal of a wide range of industrial dyes.

Mechano-chemical and biological energetics of immobilized enzymes onto functionalized polymers and their applications

Enzymes of commercial importance, such as lipase, amylase, laccase, phytase, carbonic anhydrase, pectinase, maltase, glucose oxidase etc., show multifunctional features and have been extensively used in several fields including fine chemicals, environmental, pharmaceutical, cosmetics, energy, food industry, agriculture and nutraceutical etc. The deployment of biocatalyst in harsh industrial conditions has some limitations, such as poor stability. These drawbacks can be overcome by immobilizing the enzyme in order to boost the operational stability, catalytic activity along with facilitating the reuse of biocatalyst. Nowadays, functionalized polymers and composites have gained increasing attention as an innovative material for immobilizing the industrially important enzyme. The different types of polymeric materials and composites are pectin, agarose, cellulose, nanofibers, gelatin, and chitosan. The functionalization of these materials enhances the loading capacity of the enzyme by providing more functional groups to the polymeric material and hence enhancing the enzyme immobilization efficiency. However, appropriate coordination among the functionalized polymeric materials and enzymes of interest plays an important role in producing emerging biocatalysts with improved properties. The optimal coordination at a biological, physical, and chemical level is requisite to develop an industrial biocatalyst. Bio-catalysis has become vital aspect in pharmaceutical and chemical industries for synthesis of value-added chemicals. The present review describes the current advances in enzyme immobilization on functionalized polymers and composites. Furthermore, the applications of immobilized enzymes in various sectors including bioremediation, biosensor and biodiesel are also discussed.

Sequential optimization strategy for the immobilization of Erwinia sp. D12 cells and the production of isomaltulose with high stability and prebiotic potential

Isomaltulose is a potential substitute for sucrose, with a high stability and prebiotic potential, for wide use in candies and soft drinks. This sugar is obtained from sucrose through enzymatic conversion using microbial glucosyltransferases. This work aimed to optimize a matrix to immobilize glucosyltransferase producing Erwinia sp. D12 cells using a sequential experimental strategy. The cell mass of Erwinia sp. D12 obtained in a bioreactor was immobilized in beads formed by ionic gelation. The conversion of sucrose into isomaltulose using the beads was performed in batch and continuous processes, and the isomaltulose was recovered through crystallization. The stability of isomaltulose was assessed in beverages of different pH values, and its prebiotic potential was verified with the growth of probiotic microorganisms. The optimized matrix composed of alginate (2.0% w/v), CaCl₂ (2.0% w/v), gelatin (2.0% w/v), and transglutaminase (0.2% w/v) showed the highest mean of produced isomaltulose (199.82 g/L) after four batches. In addition, high stability during the continuous process resulted in an isomaltulose production above of 230 g/L for up to 72 h. The produced isomaltulose was more stable than sucrose in lemon soft drink and orange and grape energy drinks after 30 days of storage; and promoted the growth of Bifidobacterium animalis and Lactobacillus lactis. In conclusion, the production of isomaltulose by Erwinia sp. D12 cells immobilized using optimized conditions is recommended, due to its high conversion capacity, high stability, and prebiotic potential of crystals obtained.