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1.
Arch Microbiol ; 206(9): 378, 2024 Aug 14.
Artículo en Inglés | MEDLINE | ID: mdl-39143417

RESUMEN

Human milk oligosaccharides (HMOs) have been recognized as gold standard for infant development. 3-Fucosyllactose (3-FL), being one of the Generally Recognized as Safe HMOs, represents a core trisaccharide within the realm of HMOs; however, it has received comparatively less attention in contrast to extensively studied 2'-fucosyllactose. The objective of this review is to comprehensively summarize the health effects of 3-FL, including its impact on gut microbiota proliferation, antimicrobial effects, immune regulation, antiviral protection, and brain maturation. Additionally, the discussion also covers the commercial application and regulatory approval status of 3-FL. Lastly, an organized presentation of large-scale production methods for 3-FL aims to provide a comprehensive guide that highlights current strategies and challenges in optimization.


Asunto(s)
Microbioma Gastrointestinal , Leche Humana , Trisacáridos , Trisacáridos/metabolismo , Humanos , Leche Humana/química , Oligosacáridos/metabolismo , Animales
2.
J Agric Food Chem ; 72(25): 14191-14198, 2024 Jun 26.
Artículo en Inglés | MEDLINE | ID: mdl-38878091

RESUMEN

3-Fucosyllactose (3-FL), an important fucosylated human milk oligosaccharide in breast milk, offers numerous health benefits to infants. Previously, we metabolically engineered Escherichia coli BL21(DE3) for the in vivo biosynthesis of 3-FL. In this study, we initially optimized culture conditions to double 3-FL production. Competing pathway genes involved in in vivo guanosine 5'-diphosphate-fucose biosynthesis were subsequently inactivated to redirect fluxes toward 3-FL biosynthesis. Next, three promising transporters were evaluated using plasmid-based or chromosomally integrated expression to maximize extracellular 3-FL production. Additionally, through analysis of α1,3-fucosyltransferase (FutM2) structure, we identified Q126 residues as a highly mutable residue in the active site. After site-saturation mutation, the best-performing mutant, FutM2-Q126A, was obtained. Structural analysis and molecular dynamics simulations revealed that small residue replacement positively influenced helical structure generation. Finally, the best strain BD3-A produced 6.91 and 52.1 g/L of 3-FL in a shake-flask and fed-batch cultivations, respectively, highlighting its potential for large-scale industrial applications.


Asunto(s)
Escherichia coli , Fucosiltransferasas , Ingeniería Metabólica , Trisacáridos , Escherichia coli/genética , Escherichia coli/metabolismo , Trisacáridos/metabolismo , Trisacáridos/biosíntesis , Trisacáridos/química , Fucosiltransferasas/genética , Fucosiltransferasas/metabolismo , Humanos , Oligosacáridos
3.
Food Chem ; 440: 138250, 2024 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-38154282

RESUMEN

Carbohydrate-active enzymes are accountable for the synthesis and degradation of glycosidic bonds among diverse carbohydrates. Fructosyl-transferases represent a subclass of these enzymes, employing sucrose as a substrate to generate fructooligosaccharides (FOS) and fructan polymers. This category primarily includes levansucrase (LS, EC 2.4.1.10), inulosucrase (IS, EC 2.4.1.9), and ß-fructofuranosidase (Ffase, EC 3.2.1.26). These three enzymes possess a similar five-bladed ß-propeller fold and employ an anomer-retaining reaction mechanism mediated by nucleophiles, transition state stabilizers, and general acids/bases. However, they exhibit distinct product profiles, characterized by variations in linkage specificity and molecular mass distribution. Consequently, this article comprehensively explores recent advancements in the catalytic characteristics, structural features, reaction mechanisms, and product specificity of levansucrase, inulosucrase, and ß-fructofuranosidase (abbreviated as LS, IS, and Ffase, respectively). Furthermore, it discusses the potential for modifying catalytic properties and product specificity through structure-based design, which enables the rational production of custom fructan and FOS.


Asunto(s)
Hexosiltransferasas , Transferasas , Transferasas/metabolismo , beta-Fructofuranosidasa/metabolismo , Hexosiltransferasas/metabolismo , Oligosacáridos/metabolismo , Fructanos/metabolismo , Catálisis , Sacarosa/metabolismo , Especificidad por Sustrato
4.
J Agric Food Chem ; 71(48): 18943-18952, 2023 Dec 06.
Artículo en Inglés | MEDLINE | ID: mdl-37990968

RESUMEN

Zearalenone (ZEN) and its derivatives are prevalent contaminants in cereal crops. This study investigated a novel thermostable ZEN lactonase (ZENM) from Monosporascus sp. GIB2. ZENM demonstrated its highest activity at 60 °C, maintaining over 90% relative activity from 50 to 60 °C. Notably, efficient hydrolysis of ZEN and its two derivatives was achieved using ZENM, with specific activities of 333 U/mg for ZEN, 316 U/mg for α-zearalenol (α-ZOL), and 300 U/mg for α-zearalanol (α-ZAL). The activity of ZENM toward α-ZOL is noteworthy as most ZEN lactonases rarely achieve such a high degradation rate of α-ZOL. Based on the sequence-structure analysis, five residues (L123, G163, E171, S199, and S202) conserved in other ZEN lactonases were substituted in ZENM. Of interest was the G163S mutant in the cap domain that displayed enhanced activity toward α-ZOL compared to the wild-type enzyme. Notably, the mutant G163S exhibited higher catalytic activity toward α-ZOL (kcat/Km 0.223 min-1 µM-1) than ZEN (kcat/Km 0.191 min-1 µM-1), preferring α-ZOL as its optimum substrate. In conclusion, a thermostable ZEN lactonase has been reported, and the alteration of residue G163 in the cap domain has been shown to modify the substrate specificity of ZEN lactonase.


Asunto(s)
Zearalenona , Zeranol , Zearalenona/metabolismo , Especificidad por Sustrato
5.
Crit Rev Food Sci Nutr ; : 1-18, 2023 Mar 06.
Artículo en Inglés | MEDLINE | ID: mdl-36876518

RESUMEN

Flavonoids are ubiquitous and diverse in plants and inseparable from the human diet. However, in terms of human health, their further research and application in functional food and pharmaceutical industries are hindered by their low water solubility. Therefore, flavonoid glycosylation has recently attracted research attention because it can modulate the physicochemical and biochemical properties of flavonoids. This review represents a comprehensive overview of the O-glycosylation of flavonoids catalyzed by sucrose- and starch-utilizing glycoside hydrolases (GHs). The characteristics of this feasible biosynthesis approach are systematically summarized, including catalytic mechanism, specificity, reaction conditions, and yields of the enzymatic reaction, as well as the physicochemical properties and bioactivities of the product flavonoid glycosides. The cheap glycosyl donor substrates and high yields undoubtedly make it a practical flavonoid modification approach to enhance glycodiversification.

6.
Enzyme Microb Technol ; 166: 110221, 2023 May.
Artículo en Inglés | MEDLINE | ID: mdl-36906979

RESUMEN

Currently, people pay more attention to marine sugars, because of their unique physiological effects. Alginate oligosaccharides (AOS) are the degradation products of alginate and have been used in food, cosmetic, and medicine fields. AOS display good physical characteristics (low relative molecular weight, good solubility, high safety, and high stability) and excellent physiological functions (immunomodulatory, antioxidant, antidiabetic, and prebiotic activities). Alginate lyase plays a key role in the AOS bioproduction. In this study, a novel PL-31 family alginate lyase from Paenibacillus ehimensis (paeh-aly) was identified and characterized. It was extracellularly secreted in E. coli and exhibited a preference for the substrate poly ß-D-mannuronate. Using sodium alginate as the substrate, it showed the maximum catalytic activity (125.7 U/mg) at pH 7.5 and 55 °C with 50 mM NaCl. Compared with other alginate lyases, paeh-aly exhibited good stability. About 86.6% and 61.0% residual activity could be maintained after 5 h incubation at 50 and 55 °C respectively, and its Tm value was 61.5 °C. The degradation products were AOS with DP 2-4. Paeh-aly demonstrated strong promise for AOS industrial production because of its excellent thermostability and efficiency.


Asunto(s)
Alginatos , Proteínas Bacterianas , Humanos , Proteínas Bacterianas/metabolismo , Alginatos/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Oligosacáridos/metabolismo , Polisacárido Liasas/metabolismo , Especificidad por Sustrato , Concentración de Iones de Hidrógeno
7.
Polymers (Basel) ; 15(6)2023 Mar 14.
Artículo en Inglés | MEDLINE | ID: mdl-36987215

RESUMEN

The biological production of levan by levansucrase (LS, EC 2.4.1.10) has aroused great interest in the past few years. Previously, we identified a thermostable levansucrase from Celerinatantimonas diazotrophica (Cedi-LS). A novel thermostable LS from Pseudomonas orientalis (Psor-LS) was successfully screened using the Cedi-LS template. The Psor-LS showed maximum activity at 65 °C, much higher than the other LSs. However, these two thermostable LSs showed significantly different product specificity. When the temperature was decreased from 65 to 35 °C, Cedi-LS tended to produce high-molecular-weight (HMW) levan. By contrast, Psor-LS prefers to generate fructooligosaccharides (FOSs, DP ≤ 16) rather than HMW levan under the same conditions. Notably, at 65 °C, Psor-LS would produce HMW levan with an average Mw of 1.4 × 106 Da, indicating that a high temperature might favor the accumulation of HMW levan. In summary, this study allows a thermostable LS suitable for HMW levan and levan-type FOSs production simultaneously.

8.
J Agric Food Chem ; 71(1): 680-689, 2023 Jan 11.
Artículo en Inglés | MEDLINE | ID: mdl-36538710

RESUMEN

Levansucrase (LS, EC 2.4.1.10) catalyzes the synthesis of levan by successively transferring the fructosyl moiety from sucrose to an elongated fructan chain. Although the product distribution of LS from Erwinia amylovora (Ea-LS) was studied under different sucrose concentrations, the effect of residues on the product formation is yet unknown. The first levanhexaose-complexed structure of LS from Bacillus subtilis (Bs-SacB) provided information on the oligosaccharide binding sites (OB sites), from +1 to +4 subsites. Since Ea-LS would efficiently produce fructooligosaccharides, a substitution mutation of OB sites in Bs-SacB and the corresponding residues of Ea-LS were conducted to investigate how these mutants would influence the product distribution. As a result, a series of mutants with different product spectrum were obtained. Notably, the mutants of G98E, V151F, and N200T around loop 1, loop 3, and loop 4 all showed a significant increase in both the molecular mass and the yield of high-molecular-mass levan, suggesting that the product profile of Ea-LS was significantly modified.


Asunto(s)
Erwinia amylovora , Hexosiltransferasas , Erwinia amylovora/genética , Erwinia amylovora/metabolismo , Sacarosa/metabolismo , Hexosiltransferasas/química , Fructanos/metabolismo
9.
Crit Rev Food Sci Nutr ; 63(22): 5661-5679, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-34965808

RESUMEN

D-Allulose is the C-3 epimer of D-fructose, and widely regarded as a promising substitute for sucrose. It's an excellent low-calorie sweetener, with 70% sweetness of sucrose, 0.4 kcal/g dietary energy, and special physiological functions. It has been approved as GRAS by the U.S. Food and Drug Administration, and is allowed to be excluded from total and added sugar counts on the food labels. Therefore, D-allulose gradually attracts more public attention. Owing to scarcity in nature, the bioproduction of D-allulose by using ketose 3-epimerase (KEase) has become the research hotspot. Herein, we give a summary of the physicochemical properties, physiological function, applications, and the chemical and biochemical synthesis methods of D-allulose. In addition, the recent progress in the D-allulose bioproduction using KEases, and the possible solutions for existing challenges in the D-allulose industrial production are comprehensively discussed, focusing on the molecular modification, immobilization, food-grade expression, utilizing low-cost biomass as feedstock, overcoming thermodynamic limitation, as well as the downstream separation and purification. Finally, Prospects for further development are also proposed.


Asunto(s)
Fructosa , Azúcares , Estados Unidos , Racemasas y Epimerasas , Sacarosa
10.
Crit Rev Biotechnol ; 43(2): 293-308, 2023 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-34965820

RESUMEN

Phenyllactic acid (PLA) is capable of inhibiting the growth of many microorganisms, showing a broad-spectrum antimicrobial property, which allows it to hold vast applications in the: food, feed, pharmaceutical, and cosmetic industries, especially in the field of food safety. Recently, the production of PLA has garnered considerable attention due to the increasing awareness of food safety from the public. Accordingly, this review mainly updates the recent development for the production of PLA through microbial fermentation and whole-cell catalysis (expression single-, double-, and triple-enzyme) strategies. Firstly, the: physicochemical properties, existing sources, and measurement methods of PLA are systematically covered. Then, the inhibition spectrum of PLA is summarized, and synchronously, the antimicrobial and anti-biofilm mechanisms of PLA on commonly pathogenic microorganisms in foods are described in detail, thereby clarifying the reason for extending the shelf life of foods. Additionally, the factors affecting the production of PLA are summarized from the biosynthesis and catabolism pathway of PLA in microorganisms, as well as external environmental parameters insights. Finally, the downstream treatment process and applications of PLA are discussed and outlined. In the future, clinical data should be supplemented with the metabolic kinetics of PLA in humans and to evaluate animal toxicology, to enable regulatory use of PLA as a food additive. A food-grade host, such as Bacillus subtilis and Lactococcus lactis, should also be developed as a cell vector expressing enzymes for PLA production from a food safety perspective.


Asunto(s)
Antiinfecciosos , Lactatos , Humanos , Lactatos/metabolismo , Lactatos/farmacología , Antiinfecciosos/farmacología , Biotecnología , Poliésteres
11.
Appl Microbiol Biotechnol ; 106(21): 6915-6932, 2022 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-36184691

RESUMEN

Pyrethroids, which are synthetic organic insecticides, are widely used in agriculture and households to resist pests and control disease transmission. However, pyrethroids have inevitably caused environmental pollution, leading to concerns for food safety and human health. Bioremediation has emerged as one of the most promising methods to eliminate pyrethroids compounds. Pyrethroid-degrading microorganisms and the relevant enzymes have shown an efficient ability in degrading pyrethroids by hydrolyzing the ester linkage. In this review, a wide variety of pyrethroid-degrading strains were presented and classified from different sources, such as wastewater, soils, and oceans. In addition, the recombinant expression, enzyme identification, and molecular modification of these microbial pyrethroid-degrading enzymes were also compared and discussed in detail. Moreover, the potential applications of pyrethroid-degrading enzymes, including immobilization and biodegradation towards a series of pyrethroids, were also presented. All of the positive results obtained from this review could be a good guideline for the other research in this field. KEY POINTS: • Distribution of pyrethroid-degrading strains in different sources was summarized. • Enzymatic properties including pH, temperature, and substrate specificity were compared. • Promising molecular modification and immobilization of hydrolases were present.


Asunto(s)
Insecticidas , Piretrinas , Ésteres , Hidrolasas , Insecticidas/metabolismo , Piretrinas/metabolismo , Suelo , Aguas Residuales
12.
Appl Microbiol Biotechnol ; 106(21): 6877-6886, 2022 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-36173450

RESUMEN

Zearalenone (ZEN) and its derivatives are one of the most contaminated fungal toxins worldwide, posing a severe threat to food security and human life. Traditional physical and chemical detoxifying methods are unsatisfactory due to incomplete detoxification, nutrient loss, and secondary pollutants. In recent years, bioremediation for eliminating fungal toxins has been gradually investigated. ZEN lactone hydrolase (lactonase) has been widely studied because of its high activity, mild conditions, and non-toxic product property. This review comprehensively represents the gene mining, characterization, molecular modification, and application of microbial-derived ZEN lactonases. It is aimed to elucidate the advantages and challenges of ZEN lactonases in industrial application, which also provides perspectives on obtaining innovative and promising biocatalysts for ZEN degradation. KEY POINTS: • A timely and concise review related to enzymatic elimination towards ZEN is shown. • The catalytic conditions and mechanism of ZEN lactonase is presented. • The modification and application of ZEN lactonase are exhibited also.


Asunto(s)
Contaminantes Ambientales , Micotoxinas , Zearalenona , Hidrolasas/metabolismo , Lactonas , Zearalenona/metabolismo
13.
Appl Microbiol Biotechnol ; 106(18): 5973-5986, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-36063179

RESUMEN

Carbamate pesticides are widely used in the environment, and compared with other pesticides in nature, they are easier to decompose and have less durability. However, due to the improper use of carbamate pesticides, some nontarget organisms still may be harmed. To this end, it is necessary to investigate effective removal or elimination methods for carbamate pesticides. Current effective elimination methods could be divided into four categories: physical removal, chemical reaction, biological degradation, and enzymatic degradation. Physical removal primarily includes elution, adsorption, and supercritical fluid extraction. The chemical reaction includes Fenton oxidation, photo-radiation, and net electron reduction. Biological degradation is an environmental-friendly manner, which achieves degradation by the metabolism of microorganisms. Enzymatic degradation is more promising due to its high substrate specificity and catalytic efficacy. All in all, this review primarily summarizes the property of carbamate pesticides and the traditional degradation methods as well as the promising biological elimination. KEY POINTS: • The occurrence and toxicity of carbamate pesticides were shown. • Biological degradation strains against carbamate pesticides were presented. • Promising enzymes responsible for the degradation of carbamates were discussed.


Asunto(s)
Plaguicidas , Adsorción , Carbamatos/química , Carbamatos/metabolismo , Catálisis , Plaguicidas/metabolismo
14.
J Agric Food Chem ; 70(32): 9961-9968, 2022 Aug 17.
Artículo en Inglés | MEDLINE | ID: mdl-35938974

RESUMEN

Recently, the biosynthesis of human milk oligosaccharides (HMOs) has been attracting increasing attention. Lacto-N-neotetraose (LNnT) is one of the most important neutral-core HMOs with promising health effects for infants. It has received Generally Recognized as Safe (GRAS) status and is the second HMO commercially added in infant formula after 2'-fucosyllactose. In previous studies, a series of engineered Escherichia coli strains have been constructed and optimized to produce high titers of precursor lacto-N-triose II. On the basis of these strains, LNnT-producing strains were constructed by overexpressing the ß1,4-galactosyltransferase-encoding gene from Aggregatibacter actinomycetemcomitans NUM4039 (Aa-ß1,4-GalT). Interestingly, an appreciable LNnT titer was obtained by weakening the metabolic flux of the UDP-GlcNAc pathway and simply overexpressing the essential genes lgtA, galE, and Aa-ß1,4-GalT in lacZ-, wecB-, and nagB-deleted E. coli. Subsequently, LNnT synthesis was optimized through balancing the expression of these three biosynthetic enzymes. The optimized strain produced LNnT with an extracellular titer of 12.1 g/L in fed-batch cultivation, with the productivity and specific yield of 0.25 g/L·h and 0.27 g/g dry cell weight, respectively.


Asunto(s)
Proteínas de Escherichia coli , Escherichia coli , Oligosacáridos , Carbohidrato Epimerasas/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas de Escherichia coli/metabolismo , Fórmulas Infantiles , Microorganismos Modificados Genéticamente , Leche Humana/química , Oligosacáridos/biosíntesis
15.
J Biol Chem ; 298(7): 102074, 2022 07.
Artículo en Inglés | MEDLINE | ID: mdl-35643316

RESUMEN

Many drugs and prebiotics derive their activities from sugar substituents. Due to the prevalence and complexity of these biologically active compounds, enzymatic glycodiversification that facilitates easier access to these compounds can make profound contributions to the pharmaceutical, food, and feed industries. Amylosucrases (ASases) are attractive tools for glycodiversification because of their broad acceptor substrate specificity, but the lack of structural information and their poor thermostability limit their industrial applications. Herein, we reported the crystal structure of ASase from Calidithermus timidus, which displays a homotetrameric quaternary organization not previously observed for other ASases. We employed a workflow composed of five common strategies, including interface engineering, folding energy calculations, consensus sequence, hydrophobic effects enhancement, and B-factor analysis, to enhance the thermostability of C. timidus ASase. As a result, we obtained a quadruple-point mutant M31 ASase with a half-life at 65 °C increased from 22.91 h to 52.93 h, which could facilitate biosynthesis of glucans with a degree of polymerization of more than 20 using sucrose as a substrate at 50 °C. In conclusion, this study provides a structural basis for understanding the multifunctional biocatalyst ASase and presents a powerful methodology to effectively and systematically enhance protein thermostability.


Asunto(s)
Amilosa , Glucosiltransferasas , Estabilidad de Enzimas , Glucanos , Glucosiltransferasas/metabolismo , Ingeniería de Proteínas , Especificidad por Sustrato , Sacarosa/metabolismo
16.
Mol Biotechnol ; 64(6): 650-659, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-35048315

RESUMEN

D-Mannose has great value in the treatment of chronic diseases. D-Mannose isomerase can catalyze the bioconversion of D-fructose to D-mannose. Therefore, a novel D-mannose isomerase gene (Strh-MIase) from Stenotrophomonas rhizophila strain IS26 was expressed, purified, and characterized for the industrial production of D-mannose. The specific activities of the Strh-MIase for D-mannose and D-fructose were 437.5 ± 0.8 U/mg and 267.2 ± 0.7 U/mg. Its optimal temperature and pH were 50 °C and 7.0. The enzymatic bioconversion produced 25 g/L D-mannose from concentration D-fructose (100 g/L) in 6 h by recombinant Strh-MIase, resulting in a final yield of 25%. Sodium phosphate inhibition has little influence on D-mannose production when a high concentration of D-fructose is used as substrate. We demonstrate that the metal ions improve the efficiency of D-mannose isomerase because of the enhancement of its thermostability. Moreover, the possible catalytic residues of Strh-MIase were identified by site-directed mutagenesis.


Asunto(s)
Isomerasas Aldosa-Cetosa , Manosa , Isomerasas Aldosa-Cetosa/metabolismo , Fructosa/química , Concentración de Iones de Hidrógeno , Cinética , Stenotrophomonas , Especificidad por Sustrato , Temperatura
17.
Appl Microbiol Biotechnol ; 105(21-22): 8241-8253, 2021 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-34665276

RESUMEN

In the past decades, the organophosphorus compounds had been widely used in the environment and food industries as pesticides. Owing to the life-threatening and long-lasting problems of organophosphorus insecticide (OPs), an effective detection and removal of OPs have garnered growing attention both in the scientific and practical fields in recent years. Bacterial organophosphorus hydrolases (OPHs) have been extensively studied due to their high specific activity against OPs. OPH could efficiently hydrolyze a broad range of substrates both including the OP pesticides and some nerve agents, suggesting a great potential for the remediation of OPs. In this review, the microbial identification, molecular modification, and practical application of OPHs were comprehensively discussed.Key points• Microbial OPH is a significant bioremediation tool against OPs.• Identification and molecular modification of OPH was discussed in detail.• The applications of OPH in food, environmental, and therapy fields are presented.


Asunto(s)
Insecticidas , Plaguicidas , Arildialquilfosfatasa , Biodegradación Ambiental , Compuestos Organofosforados
18.
Appl Microbiol Biotechnol ; 105(19): 7161-7170, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34515844

RESUMEN

D-Galactose is an abundant carbohydrate monomer in nature and widely exists in macroalgae, plants, and dairy wastes. D-Galactose is useful as a raw material for biomass fuel production or low-calorie sweetener production, attracting increased attention. This article summarizes the studies on biotechnological processes for galactose utilization. Two main research directions of microbial fermentation and enzyme-catalyzed conversion from galactose-rich biomass are extensively reviewed. The review provides the recent discoveries for biofuel production from macroalgae, including the innovative methods in the pretreatment process and technological development in the fermentation process. As modern people pay more attention to health, enzyme technologies for low-calorie sweetener production are more urgently needed. D-Tagatose is a promising low-calorie alternative to sugar. We discuss the recent studies on characterization and genetic modification of L-arabinose isomerase to improve the bioconversion of D-galactose to D-tagatose. In addition, the trends and critical challenges in both research directions are outlined at the end. KEY POINTS: • The value and significance of galactose utilization are highlighted. • Biofuel production from galactose-rich biomass is accomplished by fermentation. • L-arabinose isomerase is a tool for bioconversion of D-galactose to D-tagatose.


Asunto(s)
Biotecnología , Galactosa , Catálisis , Fermentación , Humanos
19.
Int J Biol Macromol ; 189: 214-222, 2021 Oct 31.
Artículo en Inglés | MEDLINE | ID: mdl-34428486

RESUMEN

Currently, low sugar and low energy have become an important trend in the food industries. Therefore, the bioconversion of the functional low-calorie rare sugars attracts more and more attention. l-Ribulose 3-epimerase (LREase) belongs to the ketose 3-epimerase (KEase) family, which could not only efficiently catalyze the reversible C-3 epimerization between l-ribulose and l-xylulose but also between d-fructose and d-allulose. In this paper, a hyperthermostable LREase from Labedella endophytica was identified and characterized. It exhibited maximum catalytic activity at pH 6.0 and 80 °C with 1 mM Ni2+. In the presence of Co2+, the t1/2 values at 60, 65, and 70 °C were 37.7, 9.0, and 4.6 h, respectively, and Tm value was 80.9 °C. From 500 g/L d-fructose, it could produce 154.2 g/L d-allulose with a conversion rate of 30.8% in 10 h. In view of its strong thermostability and high catalytic efficiency, L. endophytica LREase might be a good potential alternative for d-allulose industrial production.


Asunto(s)
Actinobacteria/enzimología , Fructosa/metabolismo , Racemasas y Epimerasas/metabolismo , Secuencia de Aminoácidos , Estabilidad de Enzimas , Concentración de Iones de Hidrógeno , Iones , Cinética , Metales , Filogenia , Racemasas y Epimerasas/química , Especificidad por Sustrato , Temperatura
20.
Int J Biol Macromol ; 186: 975-983, 2021 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-34293360

RESUMEN

L-Asparaginase (L-ASNase, EC 3.5.1.1), an antitumor drug for acute lymphoblastic leukemia (ALL) therapy, is widely used in the clinical field. Similarly, L-ASNase is also a powerful and significant biological tool in the food industry to inhibit acrylamide (AA) formation. This review comprehensively summarizes the latest achievements and improvements in the production, modification, and application of microbial L-ASNase. To date, the expression levels and optimization of expression hosts such as Escherichia coli, Bacillus subtilis, and Pichia pastoris, have made significant progress. In addition, examples of successful modification of L-ASNase such as decreasing glutaminase activity, increasing the in vivo stability, and enhancing thermostability have been presented. Impressively, the application of L-ASNase as a food addition aid, as well as its commercialization in the pharmaceutical field, and cutting-edge biosensor application developments have been summarized. The presented results and proposed ideas could be a good guide for other L-ASNase researchers in both scientific and practical fields.


Asunto(s)
Asparaginasa/biosíntesis , Bacillus subtilis/enzimología , Proteínas Bacterianas/biosíntesis , Escherichia coli/enzimología , Proteínas Fúngicas/biosíntesis , Saccharomycetales/enzimología , Antineoplásicos/química , Antineoplásicos/farmacología , Asparaginasa/química , Asparaginasa/genética , Asparaginasa/farmacología , Bacillus subtilis/genética , Proteínas Bacterianas/química , Proteínas Bacterianas/genética , Proteínas Bacterianas/farmacología , Estabilidad de Enzimas , Escherichia coli/genética , Manipulación de Alimentos , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Proteínas Fúngicas/farmacología , Microbiología Industrial , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamiento farmacológico , Conformación Proteica , Desnaturalización Proteica , Saccharomycetales/genética , Relación Estructura-Actividad , Especificidad por Sustrato , Temperatura
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