Mucic acid is a hexaric acid that can be biosynthesized by oxidation of D-galacturonic acid, which is the main constituent of pectin. The structure and properties of mucic acid are similar to that of glucaric acid, and can be widely applied in the preparation of important platform compounds, polymers and macromolecular materials. Pectin is a cheap and abundant renewable biomass resource, thus developing a process enabling production of mucic acid from pectin would be of important economic value and environmental significance. This review summarized the structure and hydrolysis of pectin, the catabolism and regulation of D-galacturonic acid in microorganisms, and the strategy for mucic acid production based on engineering of corresponding pathways. The future application of mucic acid are prospected, and future directions for the preparation of mucic acid by biological method are also proposed.
Hexuronic Acids/metabolism* ; Pectins/metabolism* ; Sugar Acids/metabolism*

The cis-epoxysuccinate hydrolase (CESH) from Rhizobium strain BK-20 is the key enzyme for L(+)-tartaric acid production. To establish a highly efficient and stable production process, we first optimized the enzyme production from Rhizobium strain BK-20, and then developed an immobilized cell-culture process for sustained production of L(+)-tartaric acid. The enzyme activity of free cells reached (3 498.0 +/- 142.6) U/g, and increased by 643% after optimization. The enzyme activity of immobilized cells reached (2 817.2 +/- 226.7) U/g, under the optimal condition with sodium alginate as carrier, cell concentration at 10% (W/V) and gel concentration at 1.5% (W/V). The immobilized cells preserved high enzyme activity and normal structure after 10 repeated batches. The conversion rate of the substrate was more than 98%, indicating its excellent production stability.
Alginates ; chemistry ; Cells, Immobilized ; Glucuronic Acid ; chemistry ; Hexuronic Acids ; chemistry ; Hydrolases ; metabolism ; Rhizobium ; enzymology ; metabolism ; Tartrates ; metabolism

In this study, we found that when Pseudomonas mendocina NK-01 accumulated intracellular carbon reserve, medium chain length poly (3-hydroxyalkanoates), it also synthesized extracellular saccharides, alginate oligosaccharides. The high carbon nitrogen ratio of culture medium facilitated alginate oligosaccharides production. We analyzed the structure of alginate oligosaccharide by Ultraviolet-Visible Spectrophotometry, Fourier Transform Infrared Spectroscopy, 1H and 13C of Nuclear Magnetic Resonance, and found that it was compounded in line from beta-D-mannuronic acids and alpha-L-gluronic acids via beta-(1-->4)/ alpha-(1-->4) bonds, which acetylated partly on the 2- and/or 3-hydroxy. In addition, we determined the weight-average molecular weight of alginate oligosaccharides by gel permeation chromatography to be 2054.
Alginates ; chemistry ; Glucuronic Acid ; biosynthesis ; chemistry ; genetics ; Hexuronic Acids ; chemistry ; Molecular Weight ; Oligosaccharides ; biosynthesis ; chemistry ; genetics ; Pseudomonas mendocina ; metabolism

Marine can be considered as a rather unexplored source of biological material. Production of algal oligosaccharides by using valuable enzymes from marine origin has become an important way to utilize marine resources. As one of algal tool enzymes, the use of alginate lyases has been focused mainly on development and application of alginate oligosaccharides with bioactive function in recent years. In this paper, we reviewed the research of alginate lyases over the past decade in several aspects, including their origin, diversity, substrate specification, mode of action, structure and catalysis mechanism, assay of enzyme activity, enzyme characterization, as well as our own experience on this subject. At the end of the review, the application prospects of alginate lyases are presented.
Alginates ; metabolism ; Glucuronic Acid ; metabolism ; Hexuronic Acids ; metabolism ; Marine Biology ; methods ; Oligosaccharides ; metabolism ; Phaeophyta ; enzymology ; Polysaccharide-Lyases ; classification ; isolation & purification ; metabolism ; Substrate Specificity

This study was intended to investigate the crosslinking characteristics of a new crosslinking agent-oxidized sodium alginate (ADA), which might provide an ideal biological crosslinking reagent for the construction of soft tissue bioprostheses. Glutaraldehyde and genipin, which have been typically used in developing bioprostheses, were used as controls. The porcine aortas were treated by these three crosslinking agents for 15 min to 72 h and the fixation index was determined. Subsequently, the mechanical property and cytocompatibility of fixed tissues were also tested. The results indicated that fixed tissues by ADA were comparable as glutaraldehyde and superior to genipin controls in fixative efficiency. It was also found that tissues fixed by ADA were comparable as genipin and superior to glutaraldehyde controls in cytocompatibility and were similar to natural tissues in mechanical property. The results of in vitro study demonstrated that ADA could be a promising crosslinking reagent for biological tissue fixation.
Alginates ; chemistry ; pharmacology ; Animals ; Aorta ; cytology ; metabolism ; Biocompatible Materials ; metabolism ; Cross-Linking Reagents ; chemistry ; pharmacology ; Extracellular Matrix ; metabolism ; Glucuronic Acid ; chemistry ; pharmacology ; Hexuronic Acids ; chemistry ; pharmacology ; Swine ; Tissue Engineering ; methods ; Tissue Fixation ; Tissue Scaffolds

To observe the effect of uniform and shift rotation culture on the formation and activity of the alginate-chitosan (AC) microencapsulated HepLL immortalized human hepatocytes and HepG2 cells aggregates.AC microcapsulated HepG2 and HepLL cells were randomly divided into two groups. Each group was divided into 3 subgroups according to uniform and shift rotation culture.The size and number of aggregates were observed and measured under laser confocal microscopy and inverted microscope dynamically. The amount of albumin synthesis was detected by ELISA, the clearance of ammonia was detected by colorimetry, and diazepam conversion function was detected by high performance liquid chromatography (HPLC).On day 6, 8, 10, 12, 14 and 16, the number and size of the aggregates, albumin synthesis, diazepam clearance and ammonium clearance increased significantly in shift rotation culture group than in uniform group (all<0.01). The albumin synthesis, diazepam clearance, and ammonium clearance in the microencapsulated HepLL groups were significantly higher than those of HepG2 cells at any time (all<0.01).Shift rotation culture can significantly promote the formation and increase the activity of AC microencapsulated HepLL and HepG2 aggregates, and HepLL cells may be more suitable for bioartificial liver than HepG2.
Albumins ; biosynthesis ; metabolism ; Alginates ; Ammonia ; metabolism ; Animals ; Cell Aggregation ; physiology ; Cell Culture Techniques ; methods ; Cell Line, Transformed ; physiology ; Chitosan ; Diazepam ; metabolism ; Glucuronic Acid ; Hep G2 Cells ; cytology ; physiology ; Hepatocytes ; cytology ; physiology ; Hexuronic Acids ; Humans ; Liver, Artificial ; Rotation

With sodium alginate as a carrier and glutaraldehyde as the crosslinking agent, an improved immobilization method of beta-glucosidase for production of soybean genistein was developed. As compared with entrapment or entrapment-crosslinkage, crosslinkage-entrapment that beta-glucosidase was treated with glutaraldehyde and then entrapped in sodium alginate remained high loading efficiency and activity recovery, Effects of bead sizes, concentrations of alginate and glutaraldehyde as well, on the loading efficiency and activity recovery were assessed. When compared with the free enzyme, the optimum temperature, pH value and Km of the immobilized beta-glucosidase were respectively shifted from 50 degrees C to 40 degrees C, 4.5 to 4.0 and 2.57 microg/mL to 2.02 miocrog/mL. The stabilities of the immobilized beta-glucosidase were considerably better than that of the native enzyme. The immobilized beta-glucosidase was employed to genistein production, 84.94% of the activity and 56.04% of conversion were kept after consecutive use of 6 times.
Alginates ; chemistry ; Aspergillus niger ; enzymology ; genetics ; Enzyme Stability ; Enzymes, Immobilized ; metabolism ; Genistein ; chemical synthesis ; chemistry ; Glucuronic Acid ; chemistry ; Glutaral ; chemistry ; Hexuronic Acids ; chemistry ; Isoflavones ; chemistry ; Soybeans ; chemistry ; beta-Glucosidase ; chemistry ; metabolism

OBJECTIVETo differentiate rat adipose tissue-derived mesenchymal stem cells (ADSCs) into cells with a nucleus pulposus-like phenotype in vitro, so as to lay a foundation for the cell-based transplantation therapy of degenerated intervertebral discs.

METHODSRat ADSCs were isolated only from the subcutaneous inguinal region and purified by limited dilution. ADSCs of the third passages were analyzed by fluorescence activated cell sorter (FACS) to detect the cell surface markers (Sca-1, CD44, CD45, CD11b). To induce ADSCs towards a nucleus pulposus-like phenotype, ADSCs were immobilized in 3-dimensional alginate hydrogels and cultured in an inducing medium containing transforming growth factor-beta1 (TGF-beta1) under hypoxia (2% O(2)), while control groups under normoxia (21% O(2)) in alginate beads in medium with or without the presence of TGF-beta1. Semiquantitative reverse transcription polymerase chain reaction (RT-PCR) was carried out to evaluate phenotypic and biosynthetic activities in the process of differentiation. Meanwhile, Alcian blue staining were used to detect the formation of sulfated glycosaminoglycans (GAGs) in the differentiated cells.

RESULTSThe purified ADSCs were fibroblast-like and proliferated rapidly in vitro. The flow cytometry showed that ADSCs were positive for Sca-1 and CD44, negative for CD45 and CD11b. The results of RT-PCR manifested that the gene expressions of Sox-9, aggrecan and collagen II, which were chondrocyte specific, were upregulated in medium containing TGF-beta1 under hypoxia (2% O(2)). Likewise, gene expression of HIF-1a, which was characteristics of intervertebral discs, was also upregulated. Simultaneously, Alcian blue staining exhibited the formation of many GAGs.

CONCLUSIONSThe approach in our experiment is a simple and effective way to acquire a large quantity of homogenous ADSCs. Rat ADSCs can be differentiated into nucleus pulposus-like cells. ADSCs may replace bone marrow mesenchymal stem cells as a new kind of seed cells in regeneration of degenerated intervertebral discs using cell transplantation therapy.

Alcian Blue ; Alginates ; Animals ; Cell Differentiation ; physiology ; Cells, Cultured ; Coloring Agents ; Flow Cytometry ; Glucuronic Acid ; Hexuronic Acids ; Male ; Mesenchymal Stromal Cells ; cytology ; metabolism ; Rats ; Rats, Sprague-Dawley ; Reverse Transcriptase Polymerase Chain Reaction ; Transforming Growth Factor beta ; pharmacology

BACKGROUNDIn recent years the interest of sustained drug delivery into inner ear is promising, at the same time a great deal of novel oral drugs using biodegradable vehicles have been produced to achieve sustained drug release. The aim of this study was to use biodegradable vehicles to release dexamethasone in the round window membrane application.

METHODSDexamethasone gels composed of alginate and chitin were prepared and the release-permeating profiles were studied using a reproducible in vitro apparatus. A longer-period time course was simulated using the parameters acquired in this study. The data obtained in this study was compared with those of other studies in intratympanic drug delivery, and an appropriate initial dosage was extrapolated.

RESULTSThe combination of alginate and chitin could efficiently restrict dexamethasone diffusion and the time course suggested a sustained drug concentration within 24 hours. A higher initial dosage was estimated to achieve a stable therapeutic concentration in vivo.

CONCLUSIONThe combination of alginate and chitin could be used as vehicle for sustained release of dexamethasone in intratympanic application.

Alginates ; administration & dosage ; Animals ; Chitosan ; administration & dosage ; Chromatography, High Pressure Liquid ; Delayed-Action Preparations ; Dexamethasone ; administration & dosage ; pharmacokinetics ; Female ; Glucuronic Acid ; administration & dosage ; Guinea Pigs ; Hexuronic Acids ; administration & dosage ; Male ; Permeability ; Pharmaceutical Vehicles ; Round Window, Ear ; metabolism

White-rot fungus manganese peroxidase (MnP) oxidizes a wide range of substrates, rendering it an interesting enzyme for potential applications. The stability of MnP can be improved by immobilization. With sodium alginate, gelatin, or chitosan as a carrier, and glutaraldehyde as the crosslinking agent, MnP was co-immobilized using the embed-crosslinked method and the adsorb-crosslinked method. The immobilization conditions and the partial properties of the three immobilized enzymes were investigated. When compared with the free enzyme, the optimum pH values and the temperatures of the three immobilized MnPs carried by alginate, gelatin, and chitosan were respectively shifted from 7.0 to 5.0, 5.0, 3.0 and from 35 degrees C to 75 degrees C , 55 degrees , 75 degrees C . The thermostabilities of the three immobilized MnPs were considerably better than that of the native enzyme. The chitosan-decreased by less than 5% even after repeated use for 6 - 9 times. The ability of decolorizing azo dyes in static and shaky situation by gelatin-immobilized MnP approached to the free enzyme, and there was no loss of enzyme activity during 2 repeated batch reactions.
Adsorption ; Alginates ; chemistry ; metabolism ; Biocatalysis ; drug effects ; Chitosan ; chemistry ; metabolism ; Dose-Response Relationship, Drug ; Enzymes, Immobilized ; chemistry ; metabolism ; Fungal Proteins ; chemistry ; metabolism ; Gelatin ; chemistry ; metabolism ; Glucuronic Acid ; chemistry ; metabolism ; Glutaral ; pharmacology ; Hexuronic Acids ; chemistry ; metabolism ; Hydrogen-Ion Concentration ; Kinetics ; Peroxidases ; chemistry ; metabolism ; Schizophyllum ; enzymology ; Substrate Specificity ; Temperature