Purification, Characterization and Degradation Performance of a Novel Dextranase from Penicillium cyclopium CICC-4022

Preparation of Sweet Potato Porous Starch by Marine Dextranase and Its Adsorption Characteristics

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.

Molecular docking and dynamics of a dextranase derived from Penicillium cyclopium CICC-4022

This study aimed to investigate the recognition mechanism of dextranase (PC-Edex) produced by Penicillium cyclopium CICC-4022 on dextran. Whole genome information of P. cyclopium CICC-4022 was obtained through genome sequencing technology. The coding information of PC-Edex was determined based on the annotation of the protein-coding genes using protein databases. The three-dimensional structure of PC-Edex was obtained via homology modelling. The active site and binding free energy between PC-Edex and dextran were calculated by molecular docking and molecular dynamics techniques. The results showed that the total sequence length and GC content of P. cyclopium CICC-4022 were 29,710,801 bp and 47.02 %, respectively. The annotation of protein-encoding genes showed that P. cyclopium CICC-4022 is highly active and has many carbohydrate transport and metabolic functions, and most of its proteases are glycolytic anhydrases. Furthermore, the gene encoding PC-Edex was successfully annotated. Molecular dynamics simulations indicated that van der Waals interaction was the main driving force of interaction. Residues Ile114, Asp115, Tyr332, Lys344, and Gln403 significantly promoted the binding between dextran and PC-Edex. In summary, this study explored the active site catalyzed by PC-Edex based on the binding pattern of PC-Edex and dextran. Therefore, this study provides genomic information on dextranase and data supporting the rational modification and enhancement of PC-Edex.

Recombinant Prevotella melaninogenica α-1,3 glucanase and Capnocytophaga ochracea α-1,6 glucanase as enzymatic tools for in vitro degradation of S. mutans biofilms

Dental biofilms represent a serious oral health problem playing a key role in the development of caries and other oral diseases. In the present work, we cloned and expressed in E. coli two glucanases, Prevotella melaninogenica mutanase (PmGH87) and Capnocytophaga ochracea dextranase (CoGH66), and characterized them biochemically and biophysically. Their three-dimensional structures were elucidated and discussed. Furthermore, we tested the capacity of the enzymes to hydrolyze mutan and dextran to prevent formation of Streptococcus mutans biofilms, as well as to degrade pre- formed biofilms in low and abundant sugar conditions. The percentage of residual biofilm was calculated for each treatment group in relation to the control, as well as the degree of synergism. Our results suggest that both PmGH87 and CoGH66 are capable of inhibiting biofilm formation grown under limited or abundant sucrose conditions. Degradation of pre-formed biofilms experiments reveal a time-dependent effect for the treatment with each enzyme alone. In addition, a synergistic and dose-dependent effects of the combined enzymatic treatment with the enzymes were observed. For instance, the highest biomass degradation was 95.5% after 30 min treatment for the biofilm grown in low sucrose concentration, and 93.8% after 2 h treatment for the biofilm grown in sugar abundant condition. Strong synergistic effects were observed, with calculated degree of synergism of 5.54 and 3.18, respectively and their structural basis was discussed. Jointly, these data can pave the ground for the development of biomedical applications of the enzymes for controlling growth and promoting degradation of established oral biofilms.

Dextranase Production Using Marine Microbacterium sp. XD05 and Its Application

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.

Review on recent advances in the properties, production and applications of microbial dextranases

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.

The inhibitory effect of dextranases from Bacillus velezensis and Pseudomonas stutzeri on Streptococcus mutans biofilm

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.

Purification and characterization of cold-adapted and salt-tolerant dextranase from Cellulosimicrobium sp. THN1 and its potential application for treatment of dental plaque

The cold-adapted and/or salt-tolerant enzymes from marine microorganisms were confirmed to be meritorious tools to enhance the efficiency of biocatalysis in industrial biotechnology. We purified and characterized a dextranase CeDex from the marine bacterium Cellulosimicrobium sp. THN1. CeDex acted in alkaline pHs (7.5-8.5) and a broad temperature range (10-50°C) with sufficient pH stability and thermostability. Remarkably, CeDex retained approximately 40% of its maximal activities at 4°C and increased its activity to 150% in 4 M NaCl, displaying prominently cold adaptation and salt tolerance. Moreover, CeDex was greatly stimulated by Mg2+, Na+, Ba2+, Ca2+ and Sr2+, and sugarcane juice always contains K+, Ca2+, Mg2+ and Na+, so CeDex will be suitable for removing dextran in the sugar industry. The main hydrolysate of CeDex was isomaltotriose, accompanied by isomaltotetraose, long-chain IOMs, and a small amount of isomaltose. The amino acid sequence of CeDex was identified from the THN1 genomic sequence by Nano LC-MS/MS and classified into the GH49 family. Notably, CeDex could prevent the formation of Streptococcus mutans biofilm and disassemble existing biofilms at 10 U/ml concentration and would have great potential to defeat biofilm-related dental caries.

Marine Bacterial Dextranases: Fundamentals and Applications

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.

Cloning of Cold-Adapted Dextranase and Preparation of High Degree Polymerization Isomaltooligosaccharide

Intestinal diseases are mainly caused by a decrease in the relative abundance of probiotics and an increase in the number of pathogenic bacteria due to dysbiosis of the intestinal flora. High degree polymerization isomaltooligosaccharide (IMO) can promote probiotic metabolism and proliferation. In this study, the dextranase (PsDex1711) gene of marine bacterial Pseudarthrobacter sp. RN22 was cloned and expressed in Escherichia coli BL21 (DE3). The optimal pH and temperature of the dextranase were 6.0 and 30 °C, respectively, showing the highest stability at 20 °C. The dextran T70 could be hydrolyzed to produce IMO3, IMO4, IMO5, and IMO6 with a high degree of polymerization. The hydrolysate of 1 mg/mL could significantly promote the growth of Lactobacillus and Bifidobacterium after 12 h culture and the formation of biofilms by 58.2%. The hydrolysates could promote the proliferation of probiotics. Furthermore, the IC50 of scavenging rate of DPPH, hydroxyl radical, and superoxide anion was less than 20 mg/mL. This study provides a crucial theoretical basis for the application of dextranase such as pharmaceutical and food industries.

Purification, Characterization, and Hydrolysate Analysis of Dextranase From Arthrobacter oxydans G6-4B

Dextran has aroused increasingly more attention as the primary pollutant in sucrose production and storage. Although enzymatic hydrolysis is more efficient and environmentally friendly than physical methods, the utilization of dextranase in the sugar industry is restricted by the mismatch of reaction conditions and heterogeneity of hydrolysis products. In this research, a dextranase from Arthrobacter oxydans G6-4B was purified and characterized. Through anion exchange chromatography, dextranase was successfully purified up to 32.25-fold with a specific activity of 288.62 U/mg protein and a Mw of 71.12 kDa. The optimum reaction conditions were 55°C and pH 7.5, and it remained relatively stable in the range of pH 7.0-9.0 and below 60°C, while significantly inhibited by metal ions, such as Ni+, Cu2+, Zn2+, Fe3+, and Co2+. Noteworthily, a distinction of previous studies was that the hydrolysates of dextran were basically isomalto-triose (more than 73%) without glucose, and the type of hydrolysates tended to be relatively stable in 30 min; dextranase activity showed a great influence on hydrolysate. In conclusion, given the superior thermal stability and simplicity of hydrolysates, the dextranase in this study presented great potential in the sugar industry to remove dextran and obtain isomalto-triose.

Purification and characterization of dextranase from Penicillium cyclopium CICC-4022 and its degradation of dextran

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 NH₄⁺ 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.

Alkalic dextranase produced by marine bacterium Cellulosimicrobium sp. PX02 and its application

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.

Removal of bacterial dextran in sugarcane juice by Talaromyces minioluteus dextranase expressed constitutively in Pichia pastoris

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 (pGAP). The increase of the transgene dosage from one to two and four copies enhanced proportionally the extracellular yield of the recombinant enzyme (r-TmDEX) 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-TmDEX 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-TmDEX 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-TmDEX. The high yield of r-TmDEX in methanol-free cultures and the low cost of the fed batch fermentation make the P. pastoris pGAP-based expression system appropriate for the large scale production of dextranase and its use for dextran removal at sugar mills.

The role of liquid-liquid phase separation in regulating enzyme activity

Liquid-liquid phase separation (LLPS) is now recognized as a common mechanism underlying regulation of enzyme activity in cells. Insights from studies in cells are complemented by in vitro studies aimed at developing a better understanding of mechanisms underlying such control. These mechanisms are often based on the influence of LLPS on the physicochemical properties of the enzyme's environment. Biochemical mechanisms underlying such regulation include the potential for concentrating reactants together, tuning reaction rates, and controlling competing metabolic pathways. LLPS is thus a powerful tool with extensive utilities at the cell's disposal, e.g. for consolidating cell survival under stress or rerouting metabolic pathways in response to the energy state of the cell. Here, we examin the evidence for how LLPS affects enzyme catalysis and begin to understand emerging concepts and expand our understanding of enzyme catalysis in living cells.

Anti-Streptococcus mutans and anti-biofilm activities of dextranase and its encapsulation in alginate beads for application in toothpaste

Background

The accumulation of plaque causes oral diseases. Dental plaque is formed on teeth surfaces by oral bacterial pathogens, particularly Streptococcus mutans, in the oral cavity. Dextranase is one of the enzymes involved in antiplaque accumulation as it can prevent dental caries by the degradation of dextran, which is a component of plaque biofilm. This led to the idea of creating toothpaste containing dextranase for preventing oral diseases. However, the dextranase enzyme must be stable in the product; therefore, encapsulation is an attractive way to increase the stability of this enzyme.

Methods

The activity of food-grade fungal dextranase was measured on the basis of increasing ratio of reducing sugar concentration, determined by the reaction with 3, 5-dinitrosalicylic acid reagent. The efficiency of the dextranase enzyme was investigated based on its minimal inhibitory concentration (MIC) against biofilm formation by S. mutans ATCC 25175. Box-Behnken design (BBD) was used to study the three factors affecting encapsulation: pH, calcium chloride concentration, and sodium alginate concentration. Encapsulation efficiency (% EE) and the activity of dextranase enzyme trapped in alginate beads were determined. Then, the encapsulated dextranase in alginate beads was added to toothpaste base, and the stability of the enzyme was examined. Finally, sensory test and safety evaluation of toothpaste containing encapsulated dextranase were done.

Results

The highest activity of the dextranase enzyme was 4401.71 unit/g at a pH of 6 and 37 °C. The dextranase at its MIC (4.5 unit/g) showed strong inhibition against the growth of S. mutans. This enzyme at 1/2 MIC also showed a remarkable decrease in biofilm formation by S. mutans. The most effective condition of dextranase encapsulation was at a pH of 7, 20% w/v calcium chloride and 0.85% w/v sodium alginate. Toothpaste containing encapsulated dextranase alginate beads produced under suitable condition was stable after 3 months of storage, while the sensory test of the product was accepted at level 3 (like slightly), and it was safe.

Conclusion

This research achieved an alternative health product for oral care by formulating toothpaste with dextranase encapsulated in effective alginate beads to act against cariogenic bacteria, like S. mutants, by preventing dental plaque.

Purification, Characterization, and Biocatalytic and Antibiofilm Activity of a Novel Dextranase from Talaromyces sp

Dextranase is a useful enzyme that catalyzes the degradation of dextran to low-molecular-weight fractions, which have many critical commercial and clinical applications. Endophytic fungi represent a source of both high heat-stable and pH-stable enzymes. In this study, from Delonix regia bark by plate assay, out of 12 isolated fungal strains, hyaline zones were detected in only one strain. By using the standard ITS rDNA sequencing analysis, the isolated strain was identified as Talaromyces sp. In the case of carbon source, in a medium containing 1% dextran T2000 as the sole carbon source, the maximum dextranase activity reached approximately 120 U/ml after incubation of 2 days where the optimum pH was 7.4. Peptone addition to the production medium as a sole nitrogen source was accompanied by a significant increase in the dextranase production. Similarly, some metal ions, such as Fe2+ and Zn2+, increased significantly enzyme production. However, there was no significant difference resulting from the addition of Cu2+. The crude dextranase was purified by ammonium sulfate fractionation, followed by Sephadex G100 chromatography with 28-fold purification. The produced dextranase was 45 kDa with an optimum activity at 37°C and a pH of 7. Moreover, the presence of MgSO4, FeSO4, and NH4SO4 increased the purified dextranase activity; however, SDS and EDTA decreased it. Interestingly, the produced dextranase expressed remarkable pH stability, temperature stability, and biofilm inhibition activity, reducing old-established biofilm by 86% and biofilm formation by 6%.