Novel transglycosylation activity of β-N-acetylglucosaminidase of Lecanicillium lecanii produced by submerged culture

Quality and staling characteristics of white bread fortified with lysozyme-hydrolyzed mealworm powder (Tenebrio molitor L.)

Edible insects have a low environmental impact but are rich in nutrients and have been promoted as alternative protein sources. However, adding insect flour to bread negatively affects the overall quality, especially loaf volume and textural properties. Furthermore, relevant studies on chitin are limited. Therefore, this study examined chitin hydrolysis using lysozymes to enhance the quality characteristics in defatted mealworm (Tenebrio molitor L.) powder (DF-M)-supplemented bread. The chitin hydrolysis degree by lysozymes was evaluated using the 3,5-dinitrosalicylic acid assay and matrix-assisted laser desorption ionization-time-of-flight mass spectrometry. The amount of chitin oligomers increased with time, and no significant difference in the hydrolysis efficiency between water and 400 mM acetate buffer was observed. Enzymatic hydrolysis improved the DF-M water- and oil-binding and antioxidant capacities. In addition, chitin hydrolysis increased the volume and softened the texture of white bread. In particular, bread supplemented with DF-M hydrolyzed for 4 h at 10 % had the highest moisture content among the mealworm-added bread groups during storage for 5 days. Moreover, sensory evaluation showed a positive effect of chitin hydrolysis on acceptability. Our findings indicate that chitin hydrolysis can improve the quality of bread containing insect additives. In conclusion, this study provides novel insights into producing high-quality and functional bakery products from edible insects by the enzymatic hydrolysis of edible insect powders and could expand the applications of edible insects as food ingredients.

Purification and characterization of a chitinase from Aeromonas media CZW001 as a biocatalyst for producing chitinpentaose and chitinhexaose

Developing chitinase suitable for the bioconversion of chitin to chitin oligosaccharides has attracted significant attention due to its benefits in environmental protection. In this study, chitinase from Aeromonas media CZW001 (AmChi) was purified and characterized. The molecular weight of AmChi was approximately 40 kDa. AmChi exhibited maximum catalytic activity at pH 8.0 with an optimum temperature of 55°C and showed broad stability between 15 and 65°C and between pH 5.0 and 9.0. AmChi was activated by Mg²⁺ , Na⁺ , and K⁺ and inhibited by Hg⁺ , Co²⁺ , Fe²⁺ , Ca²⁺ , Ag⁺ , Zn²⁺ , and EDTA. The main products of AmChi on colloidal chitin were chitinhexaose and chitinpentaose. AmChi had better substrate specificity for powdered chitin than colloidal chitin and had a higher catalytic efficiency toward (GlcNAc)₅ than colloidal chitin. AmChi inhibited fungal growth in a dose-dependent manner. These results suggest that AmChi could be used for the enzymatic degradation of chitin to produce chitinhexaose and chitinpentaose, which have several industrial applications.

Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: An update for 2019-2020

This review is the tenth update of the original article published in 1999 on the application of matrix-assisted laser desorption/ionization (MALDI) mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2020. Also included are papers that describe methods appropriate to analysis by MALDI, such as sample preparation techniques, even though the ionization method is not MALDI. The review is basically divided into three sections: (1) general aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, fragmentation, quantification and the use of arrays. (2) Applications to various structural types such as oligo- and polysaccharides, glycoproteins, glycolipids, glycosides and biopharmaceuticals, and (3) other areas such as medicine, industrial processes and glycan synthesis where MALDI is extensively used. Much of the material relating to applications is presented in tabular form. The reported work shows increasing use of incorporation of new techniques such as ion mobility and the enormous impact that MALDI imaging is having. MALDI, although invented nearly 40 years ago is still an ideal technique for carbohydrate analysis and advancements in the technique and range of applications show little sign of diminishing.

Chemoenzymatic Production and Engineering of Chitooligosaccharides and N-acetyl Glucosamine for Refining Biological Activities

Chitooligosaccharides (COS) and N-acetyl glucosamine (GlcNAc) are currently of enormous relevance to pharmaceutical, nutraceutical, cosmetics, food, and agriculture industries due to their wide range of biological activities, which include antimicrobial, antitumor, antioxidant, anticoagulant, wound healing, immunoregulatory, and hypocholesterolemic effects. A range of methods have been developed for the synthesis of COS with a specific degree of polymerization along with high production titres. In this respect, chemical, enzymatic, and microbial means, along with modern genetic manipulation techniques, have been extensively explored; however no method has been able to competently produce defined COS and GlcNAc in a mono-system approach. Henceforth, the chitin research has turned toward increased exploration of chemoenzymatic processes for COS and GlcNAc generation. Recent developments in the area of green chemicals, mainly ionic liquids, proved vital for the specified COS and GlcNAc synthesis with better yield and purity. Moreover, engineering of COS and GlcNAc to generate novel derivatives viz. carboxylated, sulfated, phenolic acid conjugated, amino derived COS, etc., further improved their biological activities. Consequently, chemoenzymatic synthesis and engineering of COS and GlcNAc emerged as a useful approach to lead the biologically-active compound-based biomedical research to an advanced prospect in the forthcoming era.