Immobilization of Cell-Associated Enzyme by Entrapping in Gluten Matrix

Immobilized enzyme for screening and identification of anti-diabetic components from natural products by ligand fishing

Diabetes is a chronic metabolic disease caused by insufficient insulin secretion and insulin resistance. Natural product is one of the most important resources for anti-diabetic drug. However, due to the extremely complex composition, this research is facing great challenges. After the advent of ligand fishing technology based on enzyme immobilization, the efficiency of screening anti-diabetic components has been greatly improved. In order to provide critical knowledge for future research in this field, the application progress of immobilized enzyme in screening anti-diabetic components from complex natural extracts in recent years was reviewed comprehensively, including novel preparation technologies and strategies of immobilized enzyme and its outstanding application prospect in many aspects. The basic principles and preparation steps of immobilized enzyme were briefly described, including entrapment, physical adsorption, covalent binding, affinity immobilization, multienzyme system and carrier-free immobilization. New formatted immobilized enzymes with different carriers, hollow fibers, magnetic materials, microreactors, metal organic frameworks, etc., were widely used to screen anti-diabetic compositions from various natural products, such as Ginkgo biloba, Morus alba, lotus leaves, Pueraria lobata, Prunella vulgaris, and Magnolia cortex. Furthermore, the challenges and future prospects in this field were put forward in this review.

Production of ascorbic acid glucoside by alginate-entrapped mycelia of Aspergillus niger

The mycelia of Aspergillus niger, cultivated in a medium containing 45 g l(-1) maltose, 66 g l(-1) yeast extract, and 5 g l(-1) K(2)HPO(4) at 30 degrees C and 200 rpm, were used as a biocatalyst in the glucosylation of ascorbic acid. Free mycelia from 3-day-old culture, when used in a 6-h reaction with maltose as the acyl donor, gave 16.07 g l(-1) ascorbic acid glucoside corresponding to a volumetric productivity of 2.68 g l(-1) h(-1) and a conversion of 67%. Mycelia from 3-day-old cultures were entrapped in calcium alginate beads and used as a catalyst in the glucosylation of ascorbic acid. An ascorbic acid-to-maltose molar ratio of 1:9 was found to be optimum, and the conversion reached 75% after 12 h. The concentration of ascorbic acid glucoside produced at this molar ratio was 17.95 g l(-1), and the productivity was 1.5 g l(-1) h(-1). The biocatalyst was repeatedly used in a fixed bed bioreactor for the synthesis of ascorbic acid glucoside and approximately 17 g l(-1) of ascorbic acid glucoside corresponding to a volumetric productivity of 1.42 g l(-1) h(-1) was produced in each use. The conversion was retained at 70% in each use. The entrapped mycelia also exhibited exceptionally high reusability and storage stability. The product was purified to 85% by anion exchange and gel permeation chromatography with a final yield of 75%.

Continuous production of neo-fructooligosaccharides by immobilization of whole cells of Penicillium citrinum

To produce neo-fructooligosaccharides (neo-FOSs) in a 500 ml continuous packed-bed reactor using whole cell immobilization of Penicillium citrinum KCCM 11663, the optimum reaction conditions were 50 degrees C, pH 6 with 600 g sucrose l-1 being fed as substrate at 1.3 ml min-1 . Under these conditions, the maximum neo-FOSs production was 49 g l-1. In a packed-bed reactor, continuous production of neo-FOSs was possible for 50 d indicating a potential for industrial production.