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Cariogenic biofilms have a matrix rich in exopolysaccharides (EPS), mutans and dextrans, that contribute to caries development. Although several physical and chemical treatments can be employed to remove oral biofilms, those are only partly efficient and use of biofilm-degrading enzymes represents an exciting opportunity to improve the performance of oral hygiene products. In the present study, a member of a glycosyl hydrolase family 66 from Flavobacterium johnsoniae (FjGH66) was heterologously expressed and biochemically characterized. The recombinant FjGH66 showed a hydrolytic activity against an early EPS-containing S. mutans biofilm, and, when associated with a α-(1,3)-glucosyl hydrolase (mutanase) from GH87 family, displayed outstanding performance, removing more than 80% of the plate-adhered biofilm. The mixture containing FjGH66 and Prevotella melaninogenica GH87 α-1,3-mutanase was added to a commercial mouthwash liquid to synergistically remove the biofilm. Dental floss and polyethylene disks coated with biofilm-degrading enzymes also degraded plate-adhered biofilm with a high efficiency. The results presented in this study might be valuable for future development of novel oral hygiene products. [ABSTRACT FROM AUTHOR]

Six lactic acid bacteria (LAB) isolated from Algerian sheep’s milk, traditional butter, date palm sap and barley, which produce dextran, mannitol, oligosaccharides and vitamin B2 have been characterized. They were identified as Leuconostoc mesenteroides (A4X, Z36P, B12 and O9) and Liquorilactobacillus mali (BR201 and FR123). Their exopolysaccharides synthesized from sucrose by dextransucrase (Dsr) were characterized as dextrans with (1,6)-d-glucopyranose units in the main backbone and branched at positions O-4, O-2 and/or O-3, with d-glucopyranose units in the side chain. A4X was the best dextran producer (4.5 g/L), while the other strains synthesized 2.1–2.7 g/L. Zymograms revealed that L. mali strains have a single Dsr with a molecular weight (Mw) of ~ 145 kDa, while the Lc. mesenteroides possess one or two enzymes with 170–211 kDa Mw. As far as we know, this is the first detection of L. mali Dsr. Analysis of metabolic fluxes from sucrose revealed that the six LAB produced mannitol (~ 12 g/L). The co-addition of maltose–sucrose resulted in the production of panose (up to 37.53 mM), an oligosaccharide known for its prebiotic effect. A4X, Z36P and B12 showed dextranase hydrolytic enzymatic activity and were able to produce another trisaccharide, maltotriose, which is the first instance of a dextranase activity encoded by Lc. mesenteroides strains. Furthermore, B12 and O9 grew in the absence of riboflavin (vitamin B2) and synthesized this vitamin, in a defined medium at the level of ~ 220 μg/L. Therefore, these LAB, especially Lc. mesenteroides B12, are good candidates for the development of new fermented food biofortified with functional compounds. [ABSTRACT FROM AUTHOR]

The preparation of porous starch by biological enzyme method is mild conditions, simple process, and environmentally sustainable. This study employed a dextranase with specific hydrolysis of α-1,6-glycosidic bonds ability to prepare porous wheat starch. The structure of the starch was analyzed by X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, and particle size analysis. The rates of starch swelling, oil and water absorption, and drug loading, as well as solubility, were measured. The results showed the formation of pores on the starch surface after treatment at 50 ℃ for 16 h, together with reduced particle sizes, while the crystal structure of the starch did not change significantly. The specific volume of the porous starch was 2.11±0.02 cm3/g, and the solubility was 9.02%±0.21%. Swelling reached 9.91%±0.22% while the water and oil absorption rates were increased to 80.12% and 78.23%, respectively. The loading rates of curcumin, dabigatran mesylate, nystatin, and ofloxacin in a 160:1 ratio reached an average of 75.07%. In vitro experiments showed that the release rate of curcumin loaded onto wheat porous starch was significantly reduced. The release rate in stomach for 2.5 h was approximately 30%, and it was approximately 40% in intestine for 5 h. The research results provided a basis for the preparation and application of wheat porous starch.

Dextranase (EC 3.2.1.11) is primarily applied in food, sugar, and pharmaceutical industries. This study focuses on using a cold shock Escherichia coli expression system to express marine dextranase SP5-Badex; enzyme activity increased about 2.2-fold compared to previous expression. This enzyme was employed to produce sweet potato porous starch, with special emphasis on the pore size of the starch. The water and oil adsorption rates of the porous starch increased by 1.43 and 1.51 times, respectively. Extensive Fourier transform infrared spectroscopy and X-ray diffraction revealed that the crystal structure of the sweet potato starch was unaltered by enzymatic hydrolysis. The adsorption capacities of the porous starch for curcumin and proanthocyanidins were 9.59 and 12.29 mg/g, respectively. Notably, the stability of proanthocyanidins was significantly enhanced through their encapsulation in porous starch. After 2.5 h of ultraviolet irradiation, the free radical scavenging rate of the encapsulated proanthocyanidins remained at 95.10%. Additionally, after 30 days of sunlight exposure, the free radical scavenging rate of the encapsulated proanthocyanidins (84.42%) was significantly higher than that (24.34%) observed in the control group. These research findings provide substantial experimental evidence for preparing sweet potato porous starch using marine dextranase. [ABSTRACT FROM AUTHOR]

Dextranases are hydrolases that exclusively catalyze the disruption of α−1,6 glycosidic bonds. A series of variant enzymes were obtained by comparing the sequences of dextranases from different sources and introducing sequence substitutions. A correlation was found between the number of amino acids in the 397–401 region and the hydrolytic process. When there were no more than 5 amino acids in the 397–401 region, the enzyme first hydrolyzed the dextran T70 to a low molecular weight dextran with a molecular weight of about 5000, then IMOs 1 1 IMOs: isomaltooligosaccharides. G: glucose, G2: maltose, G3: maltotriose, G4: maltotetraose, G5: maltopentaose, G6: maltohexaose, G7: maltoheptaose, IG2: isomaltose, IG3: isomaltotriose, IG4: isomaltotetraose, IG5: isomaltopentaose appeared in the system if the degradation continued, showing a clear sequential relationship. And when there are more than 5 amino acids in the 397–401 region, IMOs were produced at the beginning of hydrolysis and continue to increase throughout the hydrolytic process. At the same time, we investigated the enzymatic properties of the variants and found that the hydrolytic rate of A-Ca was 11 times higher than that of the original enzyme. The proportion of IMOs produced by A-Ca was 80.68%, which was nearly10% higher than the original enzyme, providing a new enzyme for the industrial preparation of IMOs. • One of the factors affecting the hydrolysis process of Aodex was determined. • Using sequence substitution method for molecular modification. • The hydrolysis rate of variant A-Ca increased by 11 times. • The proportion of IMOs produced by A-Ca was 80.68% which increased by nearly 10% compared to the WT. [ABSTRACT FROM AUTHOR]

In this study, an actinomycete was isolated from sea mud. The strain K1 was identified as Saccharomonospora sp. by 16S rDNA. The optimal enzyme production temperature, initial pH, time, and concentration of the inducer of this actinomycete strain K1 were 37 °C, pH 8.5, 72 h, and 2% dextran T20 of medium, respectively. Dextranase from strain K1 exhibited maximum activity at 8.5 pH and 50 °C. The molecular weight of the enzyme was <10 kDa. The metal ions Sr2+ and K+ enhanced its activity, whereas Fe3+ and Co2+ had an opposite effect. In addition, high-performance liquid chromatography showed that dextran was mainly hydrolyzed to isomaltoheptose and isomaltopentaose. Also, it could effectively remove biofilms of Streptococcus mutans. Furthermore, it could be used to prepare porous sweet potato starch. This is the first time a dextranase-producing actinomycete strain was screened from marine samples. [ABSTRACT FROM AUTHOR]

Dextran is an exopolysaccharide synthesized in reactions catalyzed by enzymes obtained from microbial agents of specific species and strains. Products of dextran polysaccharides with different molecular weights are suitable for diverse pharmaceutical and clinical uses. Dextran solutions have multiple characteristics, including viscosity, solubility, rheological, and thermal properties; hence, dextran has been studied for its commercial applications in several sectors. Certain bacteria can produce extracellular polysaccharide dextran of different molecular weights and configurations. Dextran products of diverse molecular weights have been used in several industries, including medicine, cosmetics, and food. This article aims to provide an overview of the reports on dextran applications in blood transfusion and clinical studies and its biosynthesis. Information has been summarized on enzyme-catalyzed reactions for dextran biosynthesis from sucrose and on the bio-transformation process of high molecular weight dextran molecules to obtain preparations of diverse molecular weights and configurations.

Dextran, a microbial metabolite of diverse molecular configurations, can be biosynthesized employing selected strains of characterized species of bacteria. Dextran molecules are secreted as an extracellular polysaccharide in the culture medium of the bacterial fermentation system. This microbially produced polymer of glucose possesses multi-faceted characteristics such as its solubility in different solvents and formation of dextran solutions of needed viscosity. Several preparations can be formulated for the desired thermal and rheological properties. Due to such multifunctional characteristics, dextran with different structural specifications is a desired polysaccharide for clinical, pharmaceutical, and food industry commercial applications. Dextran and its derivative products with various molecular weights, in a range of high and low, have established their uses in drug delivery and in analytical devices using columns packed with polysaccharide gel. Therefore, being a neutral raw material, the resourcefulness of dextran preparations of different molecular weights and linkages in their polymer configuration is important. For this purpose, several studies have been performed to produce this commercially important polysaccharide under optimized bacterial cultivation processes. This article aims to overview recently published research reports on some significant applications of dextran in the pharmaceutical and food industries. Studies conducted under optimized conditions in fermentation processes for the biosynthesis of dextran of diverse molecular configurations, which are responsible for its multifunctional properties, have been summarized. Concise information has been presented in three separate tables for each group of specific bacterial species employed to obtain this extracellular microbial polysaccharide. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Periodontal disease is a common clinical complication and has a negative impact on the quality of life and the welfare of companion dogs. Periodontal disease occurs when pathogenic bacteria are accumulated in the gingival sulcus, which favors biofilm formation. The oral health of dogs can be significantly compromised by dental plaque accumulation. Thus, this investigation demonstrates the effect of Enterococcus faecium probiotic, dextranase enzyme, and their combination on dental biofilm in the oral cavity of dogs. ANIMALS: The 30 dogs were referred to Polyclinic with no oral ulcers, severe periodontitis, and internal diseases. PROCEDURES: Dextranase enzyme, E faecium probiotic, and their combination were administered in the oral cavity of dogs. Microbiological samples were obtained from tooth surfaces and gums before and after intervention with the substances. Bacterial colonies were enumerated by using a colony counter. Also, Porphyromonas gingivalis hmuY gene expression was evaluated by reverse transcription quantitative real-time PCR analysis. RESULTS: The total colony count of the bacterial culture indicated that the dextranase enzyme, E faecium probiotic, and their combination significantly reduced the total bacteria count in the oral cavity. Moreover, in the reverse transcription quantitative real-time PCR analysis it was observed that using the combination of E faecium probiotic and dextranase enzyme decreases the hmuY gene expression of P gingivalis bacteria. CLINICAL RELEVANCE: The results clearly indicated that the dextranase enzyme and E faecium probiotic could be used as preventive agents to reduce oral biofilm in dogs. Furthermore, no side effects were observed while using these substances. [ABSTRACT FROM AUTHOR]

Dextranase, also known as glucanase, is a hydrolase enzyme that cleaves α-1,6 glycosidic bonds. In this study, a dextranase-producing strain was isolated from water samples of the Qingdao Sea and identified as Microbacterium sp. This strain was further evaluated for growth conditions, enzyme-producing conditions, enzymatic properties, and hydrolysates. Yeast extract and sodium chloride were found to be the most suitable carbon and nitrogen sources for strain growth, while sucrose and ammonium sodium were found to be suitable carbon and nitrogen sources for fermentation. The optimal pH was 7.5, with a culture temperature of 40 °C and a culture time of 48 h. Dextranase produced by strain XD05 showed good thermal stability at 40 °C by retaining more than 70% relative enzyme activity. The pH stability of the enzyme was better under a weak alkaline condition (pH 6.0–8.0). The addition of NH4+ increased dextranase activity, while Co2+ and Mn2+ had slight inhibitory effects on dextranase activity. In addition, high-performance liquid chromatography showed that dextran is mainly hydrolyzed to maltoheptanose, maltohexanose, maltopentose, and maltootriose. Moreover, it can form corn porous starch. Dextranase can be used in various fields, such as food, medicine, chemical industry, cosmetics, and agriculture. [ABSTRACT FROM AUTHOR]

In this work, dextranase was immobilized on the surface of hydroxyapatite nanowires (HAPNWs) through covalent cross-linking method. The prepared HAPNWs-NH2-dextranase was characterized by FE-SEM, XRD, TGA and FT-IR spectroscopy. The results show that the dextranase was successfully immobilized on HAPNWs by covalent cross-linking method. The properties of HAPNWs-NH2-dextranase were studied and compared with free dextranase, such as catalytic activity, kinetic constants, thermal stability and pH stability. The loading capacity, storage stability and reusability of the immobilized enzymes were investigated. HAPNWs-NH2-dextranase demonstrated better enzyme activity at higher temperatures (92.28% vs 33.08% at 70 °C) and higher pH stability (93.17% vs 57.78% at pH 7.0) than free dextranase. The loading capacity of dextranase on HAPNWs-NH2-dextranase can reach up to 868.2 mg g−1. HAPNWs-NH2-dextranase retained 83.38% of its initial activity after 12 cycles, indicating that the HAPNWs-NH2-dextranase could have great performance in industry fields. [ABSTRACT FROM AUTHOR]

Dextranase is a type of hydrolase that is responsible for catalyzing the breakdown of high-molecular-weight dextran into low-molecular-weight polysaccharides. This process is called dextranolysis. A select group of bacteria and fungi, including yeasts and likely certain complex eukaryotes, produce dextranase enzymes as extracellular enzymes that are released into the environment. These enzymes join dextran's α-1,6 glycosidic bonds to make glucose, exodextranases, or isomalto-oligosaccharides (endodextranases). Dextranase is an enzyme that has a wide variety of applications, some of which include the sugar business, the production of human plasma replacements, the treatment of dental plaque and its protection, and the creation of human plasma replacements. Because of this, the quantity of studies carried out on worldwide has steadily increased over the course of the past couple of decades. The major focus of this study is on the most current advancements in the production, administration, and properties of microbial dextranases. This will be done throughout the entirety of the review. [ABSTRACT FROM AUTHOR]

Processing aids are utilized during raw sugar manufacturing at sugarcane processing facilities to mitigate unwanted contamination from microorganisms and their associated exopolysaccharides (EPS). Microorganisms in processing facilities contribute to sugar losses through sucrose inversion and consumption, with many bacteria strains subsequently producing dextran and fructan EPS that can cause downstream issues related to viscosity and crystallization. Similar issues also result from the presence of unwanted starches from plant material in cane juices. Processing aids include biocides for bacterial inhibition, and enzymes (e.g., dextranase, amylase) to break down polysaccharides in juices. However, oxidizing biocide processing aids (e.g., sodium hypochlorite) may inhibit enzymatic processing aid activity. In this study, biocides (sodium hypochlorite, carbamate, and hop extract) and enzymes (dextranase and amylase) were simultaneously added to sugarcane juice to measure residual enzymatic activity for dextranase and amylase. The same biocides were also tested to estimate minimum inhibitory concentrations against bacterial strains isolated from Louisiana sugarcane processing facilities. These experiments provide evidence to suggest that sodium hypochlorite may interfere with enzymatic processing aid activity, with lesser/limited enzymatic inhibition from carbamates and hop extracts. Biocide susceptibility assays suggest that sodium hypochlorite has limited effectiveness against tested bacterial strains. Hop extract biocide was only effective against Gram-positive Leuconostoc while carbamate biocide showed more broad-spectrum activity against all tested strains. [ABSTRACT FROM AUTHOR]

Abstract As an indispensable enzyme for the hydrolysis of dextran, dextranase has been widely used in the fields of food and medicine. It should be noted that the weak thermostability of dextranase has become a restricted factor for industrial applications. This study aims to improve the thermostability of dextranase AoDex in glycoside hydrolase (GH) family 49 that derived from Arthrobacter oxydans KQ11. Some mutants were predicted and constructed based on B-factor analysis, PoPMuSiC and HotMuSiC algorithms, and four mutants exhibited higher heat resistance. Compared with the wild-type, mutant S357P showed the best improved thermostability with a 5.4-fold increase of half-life at 60 °C, and a 2.1-fold increase of half-life at 65 °C. Furthermore, S357V displayed the most obvious increase in enzymatic activity and thermostability simultaneously. Structural modeling analysis indicated that the improved thermostability of mutants might be attributed to the introduction of proline and hydrophobic effects, which generated the rigid optimization of the structural conformation. These results illustrated that it was effective to improve the thermostability of dextranase AoDex by rational design and site-directed mutagenesis. The thermostable mutant of dextranase AoDex has potential application value, and it can also provide references for engineering other thermostable dextranases of the GH49 family.

Dextranase can specifically hydrolyze the α-1,6 glycosidic bond in dextran, reduce the viscosity of sugarcane juice, prevent the blockage of the instrument, and increase the recovery and quality of the target product. Dextranase degrades dextran and produces oligosaccharides such as isomaltose and isomaltotriose. These oligosaccharides are not digested and absorbed by human body, which can directly enter the large intestine and selectively proliferate beneficial bacteria such as Bifidobacterium. They have the effects of moistening intestine, promoting the absorption of mineral elements and enhancing immunity. Based on the research progress at home and abroad, the article reviews the structure of dextranase, dextranase production strains, dextranase enzyme activity and improvement technology of enzymatic properties. It is found that traditional mutagenesis technology and optimization of fermentation conditions can improve dextranase to a certain extent. Through the construction of genetically engineered bacteria, the heterologous expression level of dextranase can be effectively improved, combined with enzyme immobilization technology to improve the stability and recovery rate of the enzyme under unfavorable conditions. It is widely used in oligosaccharide preparation and sugar industry. This paper provides a reference for the research direction of late dextranase.

Dextranase is widely used in sugar production, drug synthesis, material preparation, and biotechnology, among other fields. The immobilization of dextranase using nanomaterials in order to make it reusable, is a hot research topic. In this study, the immobilization of purified dextranase was performed using different nanomaterials. The best results were obtained when dextranase was immobilized on titanium dioxide (TiO2), and a particle size of 30 nm was achieved. The optimum immobilization conditions were pH 7.0, temperature 25 °C, time 1 h, and immobilization agent TiO2. The immobilized materials were characterized using Fourier-transform infrared spectroscopy, X-ray diffractometry, and field emission gun scanning electron microscopy. The optimum temperature and pH of the immobilized dextranase were 30 °C and 7.5, respectively. The activity of the immobilized dextranase was >50% even after 7 times of reuse, and 58% of the enzyme was active even after 7 days of storage at 25 °C, indicating the reproducibility of the immobilized enzyme. The adsorption of dextranase by TiO2 nanoparticles exhibited secondary reaction kinetics. Compared with free dextranase, the hydrolysates of the immobilized dextranase were significantly different, and consisted mainly of isomaltotriose and isomaltotetraose. The highly polymerized isomaltotetraose levels could reach >78.69% of the product after 30 min of enzymatic digestion. [ABSTRACT FROM AUTHOR]

Dextranase (EC 3.2.1.11) is primarily applied in food, sugar, and pharmaceutical industries. This study focuses on using a cold shock Escherichia coli expression system to express marine dextranase SP5-Badex; enzyme activity increased about 2.2-fold compared to previous expression. This enzyme was employed to produce sweet potato porous starch, with special emphasis on the pore size of the starch. The water and oil adsorption rates of the porous starch increased by 1.43 and 1.51 times, respectively. Extensive Fourier transform infrared spectroscopy and X-ray diffraction revealed that the crystal structure of the sweet potato starch was unaltered by enzymatic hydrolysis. The adsorption capacities of the porous starch for curcumin and proanthocyanidins were 9.59 and 12.29 mg/g, respectively. Notably, the stability of proanthocyanidins was significantly enhanced through their encapsulation in porous starch. After 2.5 h of ultraviolet irradiation, the free radical scavenging rate of the encapsulated proanthocyanidins remained at 95.10%. Additionally, after 30 days of sunlight exposure, the free radical scavenging rate of the encapsulated proanthocyanidins (84.42%) was significantly higher than that (24.34%) observed in the control group. These research findings provide substantial experimental evidence for preparing sweet potato porous starch using marine dextranase.

In this study, an actinomycete was isolated from sea mud. The strain K1 was identified as Saccharomonospora sp. by 16S rDNA. The optimal enzyme production temperature, initial pH, time, and concentration of the inducer of this actinomycete strain K1 were 37 °C, pH 8.5, 72 h, and 2% dextran T20 of medium, respectively. Dextranase from strain K1 exhibited maximum activity at 8.5 pH and 50 °C. The molecular weight of the enzyme was 2+ and K+ enhanced its activity, whereas Fe3+ and Co2+ had an opposite effect. In addition, high-performance liquid chromatography showed that dextran was mainly hydrolyzed to isomaltoheptose and isomaltopentaose. Also, it could effectively remove biofilms of Streptococcus mutans. Furthermore, it could be used to prepare porous sweet potato starch. This is the first time a dextranase-producing actinomycete strain was screened from marine samples.

Glycosylation, especially N-glycosylation, is one of the most common protein modifications, with immense importance at the molecular, cellular, and organismal level. Thus, accurate and reliable N-glycan analysis is essential in many areas of pharmaceutical and food industry, medicine, and science. However, due to the complexity of the cellular glycosylation process, in-depth glycoanalysis is still a highly challenging endeavor. Contamination of samples with oligosaccharide impurities (OSIs), typically linear glucose homo-oligomers, can cause further complications. Due to their physicochemical similarity to N-glycans, OSIs produce potentially overlapping signals, which can remain unnoticed. If recognized, suspected OSI signals are usually excluded in data evaluation. However, in both cases, interpretation of results can be impaired. Alternatively, sample preparation can be repeated to include an OSI removal step from samples. However, this significantly increases sample amount, time, and effort necessary. To overcome these issues, we investigated the option to enzymatically degrade and thereby remove interfering OSIs as a final sample preparation step. Therefore, we screened ten commercially available enzymes concerning their potential to efficiently degrade maltodextrins and dextrans as most frequently found OSIs. Of these enzymes, only dextranase from Chaetomium erraticum and glucoamylase P from Hormoconis resinae enabled a degradation of OSIs within only 30 min that is free of side reactions with N-glycans. Finally, we applied the straightforward enzymatic degradation of OSIs to N-glycan samples derived from different standard glycoproteins and various stem cell lysates. [ABSTRACT FROM AUTHOR]

As an indispensable enzyme for the hydrolysis of dextran, dextranase has been widely used in the fields of food and medicine. It should be noted that the weak thermostability of dextranase has become a restricted factor for industrial applications. This study aims to improve the thermostability of dextranase AoDex in glycoside hydrolase (GH) family 49 that derived from Arthrobacter oxydans KQ11. Some mutants were predicted and constructed based on B-factor analysis, PoPMuSiC and HotMuSiC algorithms, and four mutants exhibited higher heat resistance. Compared with the wild-type, mutant S357P showed the best improved thermostability with a 5.4-fold increase of half-life at 60 °C, and a 2.1-fold increase of half-life at 65 °C. Furthermore, S357V displayed the most obvious increase in enzymatic activity and thermostability simultaneously. Structural modeling analysis indicated that the improved thermostability of mutants might be attributed to the introduction of proline and hydrophobic effects, which generated the rigid optimization of the structural conformation. These results illustrated that it was effective to improve the thermostability of dextranase AoDex by rational design and site-directed mutagenesis. The thermostable mutant of dextranase AoDex has potential application value, and it can also provide references for engineering other thermostable dextranases of the GH49 family. [ABSTRACT FROM AUTHOR]

In the current study, a novel method to improve the nano-entrapment of enzymes into Ca-alginate gel was investigated to determine the synergistic effects of ultrasound combined with microwave shock (UMS). The effects of UMS treatment on dextranase enzymes' loading effectiveness (LE) and immobilization yield (IY) were investigated. By using FT-IR spectra and SEM, the microstructure of the immobilized enzyme (IE) was characterized. Additionally, the free enzyme was used as a control to compare the reusability and enzyme-kinetics characteristics of IEs produced with and without UMS treatments. The results demonstrated that the highest LE and IY were obtained when the IE was produced with a US of 40 W at 25 kHz for 15 min combined with an MS of 60 W at a shock rate of 20 s/min for 20 min, increasing the LE and the IY by 97.32 and 78.25%, respectively, when compared with an immobilized enzyme prepared without UMS treatment. In comparison with the control, UMS treatment dramatically raised the Vmax, KM, catalytic, and specificity constant values for the IE. The outcomes suggested that a microwave shock and ultrasound combination would be an efficient way to improve the immobilization of enzymes in biopolymer gel. [ABSTRACT FROM AUTHOR]

During the sugar production process, undesirable compounds such as dextrans are produced and contaminate the flow of the sugar mill, reaching levels in the fluid of more than 10,000 ppm. Dextranase is an enzyme that has different industrial applications, since it catalyzes the hydrolysis of the bonds in random sites of the dextran. Therefore, the enzyme was immobilized using synthesized ferrite magnetic nanoparticles to degrade dextran in the fermented mash, because it is suitable to reuse and has a large surface area to bind dextranase on a solid carrier for easy magnetic separation. The synthesized bare and modified nanoparticles were characterized using SEM, EDS, FTIR, and XRD and confirmed the core–shell silica by increasing the silica composition from 0.2% of bare Fe3O4 NPs to 31.3% of modified Fe3O4 NPs. Ultrasonic treatment reduced the calculated crystal size with Scherer's equation from 91.3 to 13.5 nm, providing more particles for immobilization. The solvothermal process synthesized ferrite nanoparticles (Fe3O4) and modified them with TEOS and PEI. The obtained immobilization efficiency was 28%. Perhaps it was lower; Fe3O4 degraded almost the same as the free enzyme. The percentage of dextran degradation with free enzymes and immobilized enzymes with Fe3O4 magnetic nanoparticles was 61 and 52%, respectively. [ABSTRACT FROM AUTHOR]

Background and Objectives: Dental caries is a breakdown of the teeth enamel due to harmful bacteria, lack of oral hygiene, and sugar consumption. The acid-producing bacterium Streptococcus mutans is the leading cause of dental caries. Dextranase is an enzyme that can degrade dextran to low molecular weight fractions, which have many therapeutic and industrial applications. The purpose of the present study was to isolate a novel dextranase-producing bacteria from a source (molasses). The cell-free extracts containing dextranases were tested as antibiofilm agents. Materials and Methods: Dextranase-producing bacteria were identified using phenotypic and genotypic methods such as 16S rRNA gene sequencing and enzymatic characterization. Results: The highest six dextranase-producing bacterial isolates were Bacillus species. The best conditions for dextranase productivity were obtained after 72 hours of culture time at pH 7. The addition of glucose to the medium enhanced the production of the enzymes. The cell-free extract of the six most active isolates showed remarkable activity against biofilm formation by Streptococcus mutans ATCC 25175. The highest inhibition activities reached 60% and 80% for Bacillus velezensis and Pseudomonas stutzeri, respectively. Conclusion: Therefore, our study added to the current dextranase-producing bacteria with potential as a source of dextranases. [ABSTRACT FROM AUTHOR]

The thermal stability of enzymes dramatically limits their application in the industrial field. Based on the crystal structure, we conducted a semi-rational design according to the B-factor and free energy values to improve the stability of dextranase from Streptococcus mutans (SmdexTM). The B-factor values of Asn102, Asn503, Asp501 and Asp500 were the highest predicted by B-FITTER. Then Rosetta was used to simulate the saturation mutations of Asn102, Asn503, Asp501 and Asp500. The mutated amino acid was designed according to the change of acG. The results showed that the thermal stability of N102P, N102C, D500G, and D500T was improved, and the half-lives of N102P/D500G and N102P/D500T at 45 °C were increased to 3.14 times and 2.44 times, respectively. Analyzing the interaction of amino acids by using Discovery Studio 4.5, it was observed that the thermal stability of dextranase was improved due to the increase in hydrophobicity and the number of hydrogen bonds of the mutant enzyme. The catalytic efficiency of N102P/D500T was increased. Compared with the hydrolyzed products of SmdexTM, the mutant enzymes do not change the specificity of hydrolysates. • The study provides a useful method to improve the thermal stability of dextranase according to the B-factor and ΔΔG. • The thermal stability and hydrolysis efficiency of the mutant dextranase were successfully improved. • The thermal stability of mutant enzyme is improved due to the increase of hydrogen bond, hydrophobic force and the decrease of swing amplitude of N-terminal peptide chain. [ABSTRACT FROM AUTHOR]

Dextran, a microbial metabolite of diverse molecular configurations, can be biosynthesized employing selected strains of characterized species of bacteria. Dextran molecules are secreted as an extracellular polysaccharide in the culture medium of the bacterial fermentation system. This microbially produced polymer of glucose possesses multi-faceted characteristics such as its solubility in different solvents and formation of dextran solutions of needed viscosity. Several preparations can be formulated for the desired thermal and rheological properties. Due to such multifunctional characteristics, dextran with different structural specifications is a desired polysaccharide for clinical, pharmaceutical, and food industry commercial applications. Dextran and its derivative products with various molecular weights, in a range of high and low, have established their uses in drug delivery and in analytical devices using columns packed with polysaccharide gel. Therefore, being a neutral raw material, the resourcefulness of dextran preparations of different molecular weights and linkages in their polymer configuration is important. For this purpose, several studies have been performed to produce this commercially important polysaccharide under optimized bacterial cultivation processes. This article aims to overview recently published research reports on some significant applications of dextran in the pharmaceutical and food industries. Studies conducted under optimized conditions in fermentation processes for the biosynthesis of dextran of diverse molecular configurations, which are responsible for its multifunctional properties, have been summarized. Concise information has been presented in three separate tables for each group of specific bacterial species employed to obtain this extracellular microbial polysaccharide.

Dextranase, also known as glucanase, is a hydrolase enzyme that cleaves α-1,6 glycosidic bonds. In this study, a dextranase-producing strain was isolated from water samples of the Qingdao Sea and identified as Microbacterium sp. This strain was further evaluated for growth conditions, enzyme-producing conditions, enzymatic properties, and hydrolysates. Yeast extract and sodium chloride were found to be the most suitable carbon and nitrogen sources for strain growth, while sucrose and ammonium sodium were found to be suitable carbon and nitrogen sources for fermentation. The optimal pH was 7.5, with a culture temperature of 40 °C and a culture time of 48 h. Dextranase produced by strain XD05 showed good thermal stability at 40 °C by retaining more than 70% relative enzyme activity. The pH stability of the enzyme was better under a weak alkaline condition (pH 6.0–8.0). The addition of NH4+ increased dextranase activity, while Co2+ and Mn2+ had slight inhibitory effects on dextranase activity. In addition, high-performance liquid chromatography showed that dextran is mainly hydrolyzed to maltoheptanose, maltohexanose, maltopentose, and maltootriose. Moreover, it can form corn porous starch. Dextranase can be used in various fields, such as food, medicine, chemical industry, cosmetics, and agriculture.

By assessing the polarization, colour, dextran, starch, phenols, proteins, melassigenic cations (Na+, K+) and Ca2+, reducing sugars and pH, presented study evaluates the main factors influencing non-sugars content and juice filterability in 17 raw cane sugar samples of different geographical origin. α-amylase and dextranase were applied for combined enzymatic degradation of starch and dextran as main undesirable compounds in raw cane sugar juices (15 °Brix and pH 5.5) at four different concentrations (10:12.5, 20:25, 30:37.5 and 40:50 ppm) and 55 °C during 30 min. Decrease of starch and dextran concentrations in juices remarkably increased filterability in range of 20-75% for different raw cane sugar juices. Combined enzymatic effect of α-amylase and dextranase mixture in concentration 30:37.5 ppm showed best result for improving filterability of raw cane sugar juices through reduction in starch and dextran content as main non-sugar impurities. Selecting the raw cane sugar with appropriate quality parameters facilitates the refining process. Simultaneous addition of α-amylase and dextranase mixture (30:37.5 ppm/juice) can improve filterability of low polarization raw cane sugar juice up to 41% and contribute to the refining process enhancement and thus obtention of high-quality refined cane sugar.

Abstract Dextranase is an important industrial enzyme for the preparation of isomalto‐oligosaccharides. According to the crystal structures of 20 dextranases of four classes, we summarized the structural characteristics of enzymes and the binding modes of enzymes and ligands in this paper. Based on the characteristics of the products, we analyzed the characteristics of the binding domain and functions of dextranase by means of molecular simulation and molecular docking. The relationship between the product specificity of dextranase, its catalytic pocket shape, and its catalytic mode was briefly summarized. The catalytic mechanism of dextranase was systematically discussed, which provided the basis and reference for the rational transformation of dextranase.

Background and Objectives: Dental caries is a breakdown of the teeth enamel due to harmful bacteria, lack of oral hygiene, and sugar consumption. The acid-producing bacterium Streptococcus mutans is the leading cause of dental caries. Dextranase is an enzyme that can degrade dextran to low molecular weight fractions, which have many therapeutic and industrial applications. The purpose of the present study was to isolate a novel dextranase-producing bacteria from a source (molasses). The cell-free extracts containing dextranases were tested as antibiofilm agents. Materials and Methods: Dextranase-producing bacteria were identified using phenotypic and genotypic methods such as 16S rRNA gene sequencing and enzymatic characterization. Results: The highest six dextranase-producing bacterial isolates were Bacillus species. The best conditions for dextranase productivity were obtained after 72 hours of culture time at pH 7. The addition of glucose to the medium enhanced the production of the enzymes. The cell-free extract of the six most active isolates showed remarkable activity against biofilm formation by Streptococcus mutans ATCC 25175. The highest inhibition activities reached 60% and 80% for Bacillus velezensis and Pseudomonas stutzeri, respectively. Conclusion: Therefore, our study added to the current dextranase-producing bacteria with potential as a source of dextranases.

The accumulation of plaque is produced by oral bacterial pathogens, Streptococcus mutans (S. mutans), which causes dental cavities. Dextranase can prevent dental caries by degrading dextran (the main component of plaque biofilm). However, dextranase is unstable in dental care products such as toothpaste. Therefore, this project aims to increase the stability and specificity of dextranase in toothpaste. We hypothesized that agarose encapsulation would increase dextranase stability and encapsulated hydroxyapatite nanoparticle (HA)-immobilized dextranase in toothpaste would increase biofilm (produced by S. mutans) degradation specificity. We tested the immobilization yield with a DNSA assay. The results indicated that 5 % HA was the most optimized immobilization condition. To increase the stability of the immobilized HA-dextranase by preventing dextranase degradation, agarose, a natural non-toxic polysaccharide, was used to encapsulate HA-dextranase into uniform agarose beads. To test the stability of dextranase, 1% Dextranase, 5% HA-Dextranase, and Encapsulated HA-dextranase were mixed in sodium acetate, 1 % toothpaste, and 100 % toothpaste conditions at 25 °C and 50 °C for 48 hours. The result showed that encapsulated HA-dextranase had the highest relative stability in 100% toothpaste at 50 °C. Biofilm formation of S. mutans was quantified to test the specificity of dextranase in degrading biofilm. The results showed the greatest amount of S. mutans degradation occurred with encapsulated HA-dextranase. Overall, immobilized HA-dextranase removed biofilm most effectively and increased the specificity of dextranase from agarose encapsulation. This research can be applied in formulating toothpaste with dextranase to increase dental plaque biofilm removal efficiency. [ABSTRACT FROM AUTHOR]

Dextran, a renewable hydrophilic polysaccharide, is nontoxic, highly stable but intrinsically biodegradable. The α-1, 6 glycosidic bonds in dextran are attacked by dextranase (E.C. 3.2.1.11) which is an inducible enzyme. Dextranase finds many applications such as, in sugar industry, in the production of human plasma substitutes, and for the treatment and prevention of dental plaque. Currently, dextranases are obtained from terrestrial fungi which have longer duration for production but not very tolerant to environmental conditions and have safety concerns. Marine bacteria have been proposed as an alternative source of these enzymes and can provide prospects to overcome these issues. Indeed, marine bacterial dextranases are reportedly more effective and suitable for dental caries prevention and treatment. Here, we focused on properties of dextran, properties of dextran—hydrolyzing enzymes, particularly from marine sources and the biochemical features of these enzymes. Lastly the potential use of these marine bacterial dextranase to remove dental plaque has been discussed. The review covers dextranase-producing bacteria isolated from shrimp, fish, algae, sea slit, and sea water, as well as from macro- and micro fungi and other microorganisms. It is common knowledge that dextranase is used in the sugar industry; produced as a result of hydrolysis by dextranase and have prebiotic properties which influence the consistency and texture of food products. In medicine, dextranases are used to make blood substitutes. In addition, dextranase is used to produce low molecular weight dextran and cytotoxic dextran. Furthermore, dextranase is used to enhance antibiotic activity in endocarditis. It has been established that dextranase from marine bacteria is the most preferable for removing plaque, as it has a high enzymatic activity. This study lays the groundwork for the future design and development of different oral care products, based on enzymes derived from marine bacteria. [ABSTRACT FROM AUTHOR]

Dextranase is an enzyme that specifically hydrolyzes the α-1, 6 glucoside bond. In order to improve the activity of dextranase from Arthrobacter oxidans KQ11, site-directed mutagenesis was used to modify the amino acids involved in the "tunnel-like binding site". A saturating mutation at position 507 was carried out on this basis. The mutant enzymes A356G, S357W, W507Y, and W507F with improved enzyme activities and catalytic efficiency were successfully obtained. Compared with wild type (WT), W507Y showed the specific activity increasing by 3.00 times, the k cat value increasing by 3.62 times, the K m value decreasing by 54%, and the catalytic efficiency ( k cat / K m ) increasing by 8.98 times. The three-dimensional structure analysis showed that the increase of the number of hydrogen bonds and the distance between "tunnel-like binding sites" were important factors affecting enzyme activity. Compared with WT, W507Y had a shortened distance from the residues on the other side of the "tunnel-like binding site", which made it easier to generate hydrogen binding forces. Accordingly, the substrate hydrolysis and product efflux were accelerated, which dramatically increased the enzyme activity and catalytic efficiency.

Featured Application: The dextranase variant (r–TmDEX49A–ΔSP–ΔN30) can be used for dextran removal from sugar during the production process. In the sugar industry, dextran generates difficulties in the manufacturing process. Using crude dextranase (EC 3.2.1.11) to eliminate dextran in sugar is an effective practice. In this study, a synthetic dextranase-encoding gene of the filamentous fungus Talaromyces minioluteus, lacking its putative native signal peptide (1–20 amino acids) and the next 30 amino acids (r–TmDEX49A–ΔSP–ΔN30), was fused to the Saccharomyces cerevisiae prepro α–factor (MFα–2) signal sequence and expressed in Komagataella phaffii under the constitutive GAP promoter. K. phaffii DEX49A–ΔSP–ΔN30, constitutively producing and secreting the truncated dextranase, was obtained. The specific activity of the truncated variant resulted in being nearly the same in relation to the full-length mature enzyme (900–1000 U·mg−1 of protein). At shaker scale (100 mL) in a YPG medium, the enzymatic activity was 273 U·mL−1. The highest production level was achieved in a fed-batch culture (30 h) at 5 L fermenter scale using the FM21–PTM1 culture medium. The enzymatic activity in the culture supernatant reached 1614 U·mL−1, and the productivity was 53,800 U·L−1·h−1 (53.8 mg·L−1·h−1), the highest reported thus far for a DEX49A variant. Dextran decreased r–TmDEX49A–ΔSP–ΔN30 mobility in affinity gel electrophoresis, providing evidence of carbohydrate–protein interactions. K. phaffii DEX49A–ΔSP–ΔN30 shows great potential as a methanol-free, commercial dextranase production system. [ABSTRACT FROM AUTHOR]

A highly sensitive method has been developed for accurately measuring dextranase activity using 3-methyl-2-benzothiazolinone hydrazine. This method is based on the dextran refinement and fast-dissolving approach established in this study, as well as the assay method for enzymatic hydrolysates. The measurement parameters for the reducing sugar ends were optimized by examining the slope, intercept, R2, and time stability of the standard curve of glucose solutions containing dextran. Kinetic determination was utilized to optimize enzymatic parameters and validate the method, which was subsequently utilized for the analysis of toothpaste and mouthwash. The findings suggest that the enzymatic hydrolysis follows a zero-order reaction, laying a solid foundation for the end-point assay of dextranase activity. The results demonstrated a linear correlation within the measurement range (0.7–6.5 mU/mL), exhibiting good repeatability, high sensitivity and accuracy. This method outperformed the 3,5-dinitrosalicylic acid method and circumvented potential interference from other components in toothpaste and mouthwash. [Display omitted] • Efficient isolation of large molecular weight cut-off dextran was achieved. • The rapid dissolution of dextran was achieved without gelatinization. • An endpoint assay for dextranase was established based on the zero-order hydrolysis. • This method is more accurate and sensitive than 3, 5-dinitrosalicylic acid method. • The dextranase activity in toothpaste and mouthwash can be accurately quantified. [ABSTRACT FROM AUTHOR]

Obtaining high-degree polymerized isomaltose is more difficult while achieving better prebiotic effects. We investigated the mutation specificity and enzymatic properties of SP5-Badex, a dextranase from the GH66 family of Bacillus aquimaris SP5, and determined its mutation sites through molecular docking to obtain five mutants, namely E454K, E454G, Y539F, N369F, and Y153N. Among them, Y539F and Y153N exhibited no enzymatic activity, but their hydrolysates included isomaltotetraose (IMO4). The enzymatic activity of E454G was 1.96 U/ml, which was 3.08 times higher than that before mutation. Moreover, 70% of the enzymatic activity could be retained after holding at 45°C for 180 min, which was 40% higher than that of SP5-Badex. Furthermore, its IMO4 content was 5.62% higher than that of SP5-Badex after hydrolysis at 30°C for 180 min. To investigate the effect of different amino acids on the same mutation site, saturation mutation was induced at site Y153, and the results showed that the enzyme activity of Y153W could be increased by 2 times, and some of the enzyme activity could still be retained at 50°C. Moreover, the enzyme activity increased by 50% compared with that of SP5-Badex after holding at 45°C for 180 min, and the IMO4 content of Y153W was approximately 64.97% after hydrolysis at 30°C for 180 min, which increased by approximately 12.47% compared with that of SP5-Badex. This site is hypothesized to rigidly bind to nonpolar (hydrophobic) amino acids to improve the stability of the protein structure, which in turn improves the thermal stability and simultaneously increases the IMO4 yield.

Dextranase, a hydrolase with wide applications mainly in the sugar industry and in producing valuable prebiotics has been immobilized by different strategies. However, in the present study, successful covalent cross-linking of dextranase in the form of aggregates (CLAD) without support is established. The precipitated dextranase molecules (300 mM ammonium sulfate) were cross-linked through glutaraldehyde (150 mM) at 25 °C within 3.0 h to improve dextranase activity (140 Umg−1). The comparative analysis of CLAD with free showed no change in reaction time and optimum pH while thermal, pH, and storage stability of dextranase was enhanced after aggregation. The reusability of CLAD was also superior with 50% residual activity after 14 cycles. Besides these, thin-layer chromatography (TLC) revealed the endolytic behavior of dextranase that released oligosaccharides upon continuous hydrolytic action. The outcomes of the current strategy will help to make the enzyme cost-effective with improved stability and reusability. [Display omitted] • Crosslinked aggregates of Dextranase (CLAD) were synthesized using glutaraldehyde. • Salt precipitation followed by covalent cross-linking of dextranase was used for CLAD synthesis. • Improved kinetics characteristics of CLAD were noted compared to soluble dextranase. [ABSTRACT FROM AUTHOR]

Dextranase is widely used in sugar production, drug synthesis, material preparation, and biotechnology, among other fields. The immobilization of dextranase using nanomaterials in order to make it reusable, is a hot research topic. In this study, the immobilization of purified dextranase was performed using different nanomaterials. The best results were obtained when dextranase was immobilized on titanium dioxide (TiO2), and a particle size of 30 nm was achieved. The optimum immobilization conditions were pH 7.0, temperature 25 °C, time 1 h, and immobilization agent TiO2. The immobilized materials were characterized using Fourier-transform infrared spectroscopy, X-ray diffractometry, and field emission gun scanning electron microscopy. The optimum temperature and pH of the immobilized dextranase were 30 °C and 7.5, respectively. The activity of the immobilized dextranase was >50% even after 7 times of reuse, and 58% of the enzyme was active even after 7 days of storage at 25 °C, indicating the reproducibility of the immobilized enzyme. The adsorption of dextranase by TiO2 nanoparticles exhibited secondary reaction kinetics. Compared with free dextranase, the hydrolysates of the immobilized dextranase were significantly different, and consisted mainly of isomaltotriose and isomaltotetraose. The highly polymerized isomaltotetraose levels could reach >78.69% of the product after 30 min of enzymatic digestion.

The food enzyme dextranase (6‐α‐d‐glucan 6‐glucanohydrolase, EC 3.2.1.11) is produced with the non‐genetically modified Collariella gracilis strain AE‐DX by Amano Enzyme Inc. The food enzyme is considered free from viable cells of the production organism. The food enzyme is intended to be used in refined sugar production from sugar beet or sugar cane. Since residual amounts of total organic solids (TOS) are removed by crystallisation during the production of refined white sucrose, dietary exposure was not considered necessary for refined sugars. However, beet molasses and cane syrups, by‐products from sugar production, could enter the food chain. Based on the maximum use levels recommended, dietary exposure was estimated to be up to 0.39 mg TOS/kg body weight (bw) per day via the consumption of unrefined sugars. Genotoxicity tests did not indicate a safety concern. The systemic toxicity was assessed by means of a repeated dose 90‐day oral toxicity study in rats. The Panel identified a lowest observed adverse effect level (LOAEL) of 940.5 mg TOS/kg bw per day, the lowest dose tested, which when compared with the estimated dietary exposure, results in a margin of exposure of more than 800. A search for similarity of the amino acid sequence of the food enzyme to known allergens was made and no matches were found. The Panel considered that, under the intended conditions of use, the risk of allergic sensitisation and elicitation reactions by dietary exposure cannot be excluded, but the likelihood for this to occur is considered to be low. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use. [ABSTRACT FROM AUTHOR]

A dextranase was purified from Penicillium cyclopium CICC-4022 by ammonium sulfate fractionation and secondary tangential flow filtration, and the enzymatic properties were studied. The purified dextranase was used to regulated the molecular mass and homogeneity of dextran. Weight-average molecular mass (Mw) and polydispersity index (Mw/Mn) of dextran were measured by gel permeation chromatography (GPC) coupled with a triple-detector array (GPC-TDA), which is composed of a multiple-angle light scattering, a viscometer, and a refractive-index detector. The dextranase was purified by 2.24-fold, the recovery rate was 45.84%, the specific activity was 1442.05 U/mg, and the Mw was 77 KDa. Dextranase showed maximum activity at pH of 5.0 and 55 °C. Na+, K+ and NH 4 + can effectively improve the dextranase activity, Cu2+ and Pb2+ can strongly inhibit the dextranase activity. Dextranase specifically degraded the α-1,6 glycosidic bonds of dextran. By controlling the dextranase activity, substrate concentration, and time, the specific Mw dextran with good homogeneity was obtained. The structure of dextran was not altered before or after dextranase hydrolysis, but its conformation changed from a spherical chain to a compliant chain. When the Mw of the dextran product was about 5 KDa, it was a compact spherical chain conformation in solution. [Display omitted] • Dextranase was high efficiently purified by (NH 4) 2 SO 4 fractionation and secondary tangential flow filtration. • The dextranase from Penicillium cyclopium can specifically degrade the α-1,6 glycosidic bonds of dextran. • Under certain conditions, the molecular mass and homogeneity of dextran can be regulated by dextranase. • The conformation of dextran changed to a certain extent during the dextranase hydrolysis. [ABSTRACT FROM AUTHOR]

Abstract The food enzyme dextranase (6‐α‐d‐glucan 6‐glucanohydrolase, EC 3.2.1.11) is produced with the non‐genetically modified Collariella gracilis strain AE‐DX by Amano Enzyme Inc. The food enzyme is considered free from viable cells of the production organism. The food enzyme is intended to be used in refined sugar production from sugar beet or sugar cane. Since residual amounts of total organic solids (TOS) are removed by crystallisation during the production of refined white sucrose, dietary exposure was not considered necessary for refined sugars. However, beet molasses and cane syrups, by‐products from sugar production, could enter the food chain. Based on the maximum use levels recommended, dietary exposure was estimated to be up to 0.39 mg TOS/kg body weight (bw) per day via the consumption of unrefined sugars. Genotoxicity tests did not indicate a safety concern. The systemic toxicity was assessed by means of a repeated dose 90‐day oral toxicity study in rats. The Panel identified a lowest observed adverse effect level (LOAEL) of 940.5 mg TOS/kg bw per day, the lowest dose tested, which when compared with the estimated dietary exposure, results in a margin of exposure of more than 800. A search for similarity of the amino acid sequence of the food enzyme to known allergens was made and no matches were found. The Panel considered that, under the intended conditions of use, the risk of allergic sensitisation and elicitation reactions by dietary exposure cannot be excluded, but the likelihood for this to occur is considered to be low. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.

Featured Application: The results of the current study aid in developing a potent mouthwash formulation to maintain and improve oral health in healthy people. This study analyzed the alteration of oral microbial composition in healthy subjects after using dextranase-containing mouthwash (DMW; Mouthwash formulation I) and dextranase-and-nisin-containing mouthwash (DNMW; Mouthwash formulation II). Eighteen participants were recruited and were randomly allocated to two groups: G1 (DMW user; n = 8) and G2 (DNMW user; n = 10). The subjects were instructed to use the provided mouthwash regularly twice a day for 30 days. The bleeding on probing (BOP), plaque index (PI), probing depth (PBD), and gingival index (GI) were analyzed, and saliva samples were collected before (day 0) and after (day 30) the use of mouthwashes. The saliva metagenomic DNA was extracted and sequenced (next-generation sequencing, Miseq paired-end Illumina 2 × 250 bp platform). The oral microbial community in the pre-and post-treated samples were annotated using QIIME 2™. The results showed the PI and PBD values were significantly reduced in G2 samples. The BOP and GI values of both groups were not significantly altered. The post-treated samples of both groups yielded a reduced amount of microbial DNA. The computed phylogenetic diversity, species richness, and evenness were reduced significantly in the post-treated samples of G2 compared to the post-treated G1 samples. The mouthwash formulations also supported some pathogens' growth, which indicated that formulations required further improvement. The study needs further experiments to conclude the results. The study suggested that the improved DNMW could be an adjuvant product to improve oral hygiene. [ABSTRACT FROM AUTHOR]

Glycosylation, especially N-glycosylation, is one of the most common protein modifications, with immense importance at the molecular, cellular, and organismal level. Thus, accurate and reliable N-glycan analysis is essential in many areas of pharmaceutical and food industry, medicine, and science. However, due to the complexity of the cellular glycosylation process, in-depth glycoanalysis is still a highly challenging endeavor. Contamination of samples with oligosaccharide impurities (OSIs), typically linear glucose homo-oligomers, can cause further complications. Due to their physicochemical similarity to N-glycans, OSIs produce potentially overlapping signals, which can remain unnoticed. If recognized, suspected OSI signals are usually excluded in data evaluation. However, in both cases, interpretation of results can be impaired. Alternatively, sample preparation can be repeated to include an OSI removal step from samples. However, this significantly increases sample amount, time, and effort necessary. To overcome these issues, we investigated the option to enzymatically degrade and thereby remove interfering OSIs as a final sample preparation step. Therefore, we screened ten commercially available enzymes concerning their potential to efficiently degrade maltodextrins and dextrans as most frequently found OSIs. Of these enzymes, only dextranase from Chaetomium erraticum and glucoamylase P from Hormoconis resinae enabled a degradation of OSIs within only 30 min that is free of side reactions with N-glycans. Finally, we applied the straightforward enzymatic degradation of OSIs to N-glycan samples derived from different standard glycoproteins and various stem cell lysates.

In the current study, a novel method to improve the nano-entrapment of enzymes into Ca-alginate gel was investigated to determine the synergistic effects of ultrasound combined with microwave shock (UMS). The effects of UMS treatment on dextranase enzymes’ loading effectiveness (LE) and immobilization yield (IY) were investigated. By using FT-IR spectra and SEM, the microstructure of the immobilized enzyme (IE) was characterized. Additionally, the free enzyme was used as a control to compare the reusability and enzyme-kinetics characteristics of IEs produced with and without UMS treatments. The results demonstrated that the highest LE and IY were obtained when the IE was produced with a US of 40 W at 25 kHz for 15 min combined with an MS of 60 W at a shock rate of 20 s/min for 20 min, increasing the LE and the IY by 97.32 and 78.25%, respectively, when compared with an immobilized enzyme prepared without UMS treatment. In comparison with the control, UMS treatment dramatically raised the Vmax, KM, catalytic, and specificity constant values for the IE. The outcomes suggested that a microwave shock and ultrasound combination would be an efficient way to improve the immobilization of enzymes in biopolymer gel.

Dextran is an exopolysaccharide synthesized in reactions catalyzed by enzymes obtained from microbial agents of specific species and strains. Products of dextran polysaccharides with different molecular weights are suitable for diverse pharmaceutical and clinical uses. Dextran solutions have multiple characteristics, including viscosity, solubility, rheological, and thermal properties; hence, dextran has been studied for its commercial applications in several sectors. Certain bacteria can produce extracellular polysaccharide dextran of different molecular weights and configurations. Dextran products of diverse molecular weights have been used in several industries, including medicine, cosmetics, and food. This article aims to provide an overview of the reports on dextran applications in blood transfusion and clinical studies and its biosynthesis. Information has been summarized on enzyme-catalyzed reactions for dextran biosynthesis from sucrose and on the bio-transformation process of high molecular weight dextran molecules to obtain preparations of diverse molecular weights and configurations., Competing Interests: The authors declare no conflict of interest., (© 2024 The Author(s). Published by IMR Press.)

The enzyme dextranase is widely used in the sugar and food industries, as well as in the medical field. Most land‐derived dextranases are produced by fungi and have the disadvantages of long production cycles, low tolerance to environmental conditions, and low safety. The use of marine bacteria to produce dextranases may overcome these problems. In this study, a dextranase‐producing bacterium was isolated from the Rizhao seacoast of Shandong, China. The bacterium, denoted as PX02, was identified as Cellulosimicrobium sp. and its growing conditions and the production and properties of its dextranase were investigated. The dextranase had a molecular weight of approximately 40 kDa, maximum activity at 40°C and pH 7.5, with a stability range of up to 45°C and pH 7.0–9.0. High‐performance liquid chromatography showed that the dextranase hydrolyzed dextranT20 to isomaltotriose, maltopentaose, and isomaltooligosaccharides. Hydrolysis by dextranase produced excellent antioxidant effects, suggesting its potential use in the health food industry. Investigation of the action of the dextranase on Streptococcus mutans biofilm and scanning electron microscopy showed that it to be effective both for removing and inhibiting the formation of biofilms, suggesting its potential application in the dental industry. [ABSTRACT FROM AUTHOR]

• First report of constitutive high-level expression of dextranase in recombinant Pichia pastoris. • The increase of transgene copies enhanced dextranase yield in high cell-density cultures. • A crude dextranase preparation removed dextran in cane juice samples from sugar mill. A gene construct encoding the mature region of Talaromyces minioluteus dextranase (EC 3.2.1.11) fused to the Saccharomyces cerevisiae SUC2 signal sequence was expressed in Pichia pastoris under the constitutive glyceraldehyde 3–phosphate dehydrogenase promoter (p GAP). The increase of the transgene dosage from one to two and four copies enhanced proportionally the extracellular yield of the recombinant enzyme (r- Tm DEX) without inhibiting cell growth. The volumetric productivity of the four-copy clone in fed batch fermentation (51 h) using molasses as carbon source was 1706 U/L/h. The secreted N -glycosylated r- Tm DEX was optimally active at pH 4.5–5.5 and temperature 50–60 °C. The addition of sucrose (600 g/L) as a stabilizer retained intact the r- Tm DEX activity after 1-h incubation at 50–60 °C and pH 5.5. Bacterial dextran in deteriorated sugarcane juice was completely removed by applying a crude preparation of secreted r- Tm DEX. The high yield of r- Tm DEX in methanol-free cultures and the low cost of the fed batch fermentation make the P. pastoris p GAP -based expression system appropriate for the large scale production of dextranase and its use for dextran removal at sugar mills. [ABSTRACT FROM AUTHOR]

The hydrolysis product of dextranase contains highly polymerized oligomeric isomaltose, which can be used as prebiotics to promote the colonization of probiotics, thus adjusting the ecological environment of intestinal flora. In this study, the expression of dextranase (PsDex1711) in Bacillus subtilis WB600 was enhanced by screening signal peptides. Furthermore, the potential application of dextranase for functional starch preparation was explored. Initially, a signal peptide library was constructed to identify the most efficient signal peptide for PsDex1711 secretion. Then, enzymatic hydrolysis was employed to produce porous buckwheat starch with varying pore sizes, and the impact of this enzymatic treatment on the physicochemical and microstructural properties of buckwheat starch was investigated. Signal peptide of the YwoF protein of unknown function demonstrated the highest extracellular PsDex1711 activity at 2.10 ± 0.036 U/mL. Moreover, scanning electron microscope analysis revealed the development of deeper pores on the surface of starch granules after 18 h of enzymatic treatment, indicating the microstructural alterations induced by the enzymatic process and providing a foundation for further research in this field. The enzymatic hydrolysis also resulted in 40% and 35% increase in the water and oil absorption, respectively, compared to natural starch. Based on x-ray diffraction and Fourier transform infrared spectroscopy, it was inferred that the porous starch had a high degree of short-range ordering, which could provide a theoretical basis for the development and application of porous starch materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • Dextranase can hydrolyze dextran into oligodextrans with various sizes. • Dextranase has great application potential in the sugar-making, oral health care, medicine, and biotechnology industries. • The thermostability of bacterial dextranases is generally better than that of fungal dextranases. • The catalytic mechanisms of dextranase remain largely unknown. Dextran, an α-glucan mainly composed of (α1 → 6) linkages, has been widely applied in the food, cosmetic, and medicine industries. Dextranase can hydrolyze dextran to synthesize oligodextrans, which show prominent properties and promising applications in the food industry. Dextranases are widely distributed in bacteria, yeasts, and fungus, and classified into glycoside hydrolase (GH) 13, 15, 31, 49, and 66 families according to their sequence similarity, structural features, and reaction types. Dextranase, as a dextran-hydrolyzing enzyme, displays great application potential in the sugar-making, oral health care, medicine, and biotechnology industries. Here we mainly focused on presenting the enzymatic properties, structural features, and versatile (potential) applications of dextranase. To date, seven crystal structures of dextranases from GH 13, 15, 31, 49, and 66 families have been successfully solved. However, their molecular mechanisms for hydrolyzing dextran, especially on the size determinants of the hydrolysates, remain largely unknown. Additionally, the classification, microbial distribution, and immobilization technology of dextranase were also discussed in detail. This review discussed dextranase from different aspects with the ambition to present how they constitute the groundwork for promising future developments. [ABSTRACT FROM AUTHOR]