Characterization of a new α-l-fucosidase isolated from Fusarium proliferatum LE1 that is regioselective to α-(1 → 4)-l-fucosidic linkage in the hydrolysis of α-l-fucobiosides

Preparation and bioactivities of low-molecular weight fucoidans and fuco-oligosaccharides: A review

Fucoidans are a kind of naturally sulfated polysaccharides that are primarily derived from brown algae and marine invertebrates. They are mainly composed of L-fucose and sulphate group. In the past decades, fucoidans have been attracted much attention for its wide range of pharmacological activities. However, fucoidans are difficult to be absorbed due to their high molecular weight. Notably, low-molecular weight fucoidan (LMWF) and fuco-oligosaccharide are more readily absorbed and have equal or superior biological activities. Therefore, degradation of fucoidan has become a research hot spot in recent years. Presently, methods for fucoidan degradation primary include enzymatic degradation, chemical degradation, and physical degradation. Enzymatic degradation has advantages of mild hydrolysis conditions, good selectivity and few by-products. Chemical degradation is characterized by simple operation, low cost, and easy for industrial applications. This review article summarizes research progress on fucoidan-degrading enzymes, preparation of LMWF and fuco-oligosaccharides by enzymatic degradation, physical degradation, and chemical degradation, and biological activities of these products. This article provides information useful for chemists that are interested in preparation of LMWF and fuco-oligosaccharides, for pharmacologists that are devoted to develop fucoidan-derived bioactive molecules, and for manufacturers of fucoidan-derived products, thus promoting transformation of these products in food and pharmaceutical areas.

Fucoidans of Brown Algae: Comparison of Sulfated Polysaccharides from Fucus vesiculosus and Ascophyllum nodosum

Preparations of sulfated polysaccharides obtained from brown algae are known as fucoidans. These biopolymers have attracted considerable attention due to many biological activities which may find practical applications. Two Atlantic representatives of Phaeophyceae, namely, Fucus vesiculosus and Ascophyllum nodosum, belonging to the same order Fucales, are popular sources of commercial fucoidans, which often regarded as very similar in chemical composition and biological actions. Nevertheless, these two fucoidan preparations are polysaccharide mixtures which differ considerably in amount and chemical nature of components, and hence, this circumstance should be taken into account in the investigation of their biological properties and structure-activity relationships. In spite of these differences, fractions with carefully characterized structures prepared from both fucoidans may have valuable applications in drug development.

Perspectives for the Use of Fucoidans in Clinical Oncology

Fucoidans are natural sulfated polysaccharides that have a wide range of biological functions and are regarded as promising antitumor agents. The activity of various fucoidans and their derivatives has been demonstrated in vitro on tumor cells of different histogenesis and in experiments on mice with grafted tumors. However, these experimental models showed low levels of antitumor activity and clinical trials did not prove that this class of compounds could serve as antitumor drugs. Nevertheless, the anti-inflammatory, antiangiogenic, immunostimulating, and anticoagulant properties of fucoidans, as well as their ability to stimulate hematopoiesis during cytostatic-based antitumor therapy, suggest that effective fucoidan-based drugs could be designed for the supportive care and symptomatic therapy of cancer patients. The use of fucoidans in cancer patients after chemotherapy and radiation therapy might promote the rapid improvement of hematopoiesis, while their anti-inflammatory, immunomodulatory, and anticoagulant effects have the potential to improve the quality of life of patients with advanced cancer.

A novel acid-tolerant β-xylanase from Scytalidium candidum 3C for the synthesis of o-nitrophenyl xylooligosaccharides

Endo-β-xylanases are hemicellulases involved in the conversion of xylans in plant biomass. Here, we report a novel acidophilic β-xylanase (ScXynA) with high transglycosylation abilities that was isolated from the filamentous fungus Scytalidium candidum 3C. ScXynA was identified as a glycoside hydrolase family 10 (GH10) dimeric protein, with a molecular weight of 38 ± 5 kDa per subunit. The enzyme catalyzed the hydrolysis of different xylans under acidic conditions and was stable in the pH range 2.6-4.5. The kinetic parameters of ScXynA were determined in hydrolysis reactions with p-nitrophenyl-β-d-cellobioside (pNP-β-Cel) and p-nitrophenyl-β-d-xylobioside (pNP-β-Xyl₂ ), and k_cat /K_m was found to be 0.43 ± 0.02 (s·mM)^-1 and 57 ± 3 (s·mM)^-1 , respectively. In the catalysis of the transglycosylation o-nitrophenyl-β-d-xylobioside (oNP-β-Xyl₂ ) acted both as a donor and an acceptor, resulting in the efficient production of o-nitrophenyl xylooligosaccharides, with a degree of polymerization of 3-10 and o-nitrophenyl-β-d-xylotetraose (oNP-β-Xyl₄ ) as the major product (18.5% yield). The modeled ScXynA structure showed a favorable position for ligand entry and o-nitrophenyl group accommodation in the relatively open -3 subsite, while the cleavage site was covered with an extended loop. These structural features provide favorable conditions for transglycosylation with oNP-β-Xyl₂ . The acidophilic properties and high transglycosylation activity make ScXynA a suitable choice for various biotechnological applications, including the synthesis of valuable xylooligosaccharides.

Application of Immobilized Enzymes in Food Industry

Enzymes are macromolecular biocatalysts, widely used in food industry. In applications, enzymes are often immobilized on inert and insoluble carriers, which increase their efficiency due to multiple reusability. The properties of immobilized enzymes depend on the immobilization method and the carrier type. The choice of the carrier usually concerns the biocompatibility, chemical and thermal stability, insolubility under reaction conditions, capability of easy regeneration and reusability, as well as cost efficiency. In this review, we provide an overview of various carriers for enzyme immobilization, with the primary focus on food industry.

Synthesis of Fucosyl-Oligosaccharides Using α-l-Fucosidase from Lactobacillus rhamnosus GG

Fucosyl-oligosaccharides are natural prebiotics that promote the growth of probiotics in human gut and stimulate the innate immune system. In this work, the release of α-lfucosidase by Lactobacillus rhamnosus GG, and the use of this enzyme for the synthesis of fucosyl-oligosaccharides were investigated. Since α-lfucosidase is a membrane-bound enzyme, its release from the cells was induced by addition of 4-nitrophenyl-α-l-fucopyranoside (pNP-Fuc). Enzyme activity associated with the cell was recovered at 78% of its total activity. Fucosyl-oligosaccharides where synthesized using α-l-fucosidase extract and pNP-Fuc as donor substrate, and D-lactose or D-lactulose as acceptor substrates, reaching a yield up to 25%. Fucosyllactose was obtained as a reaction product with D-lactose, and its composition was confirmed by mass spectrometry (MALDI-TOF MS). It is possible that the fucosyl-oligosaccharide synthesized in this study has biological functions similar to human milk oligosaccharides.

Employment of fucosidases for the synthesis of fucosylated oligosaccharides with biological potential

Fucosylated oligosaccharides play important physiological roles in humans, including in the immune response, transduction of signals, early embryogenesis and development, growth regulation, apoptosis, pathogen adhesion, and so on. Efforts have been made to synthesize fucosylated oligosaccharides, as it is difficult to purify them from their natural sources, such as human milk, epithelial tissue, blood, and so on. Within the strategies for its in vitro synthesis, it is remarkable the employment of fucosidases, enzymes that normally cleave the fucosyl residue from the non-reducing end of fucosylated compounds, as these enzymes are also capable of synthesizing them by means of a transfucosylation reaction. This review summarizes the progress in the use of fucosidases for the synthesis of compounds that have potential for industrial and commercial applications.