Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 14 de 14
Filtrar
1.
Prep Biochem Biotechnol ; : 1-12, 2024 May 14.
Artículo en Inglés | MEDLINE | ID: mdl-38742596

RESUMEN

In order to improve the utilization value of the erythritol mother liquor, the separation and purification of the erythritol mother liquor was selected in this study. The selected chromatographic separation programme for erythritol crystallizing mother liquor is as follows: Firstly, erythritol is resolved from mannitol and arabitol with DTF-01Ca (Suqing Group) resin and then mannitol is resolved from arabitol with 99Ca/320 (Dowex) resin. At the same time, the chromatographic conditions of the DTF-01Ca (Suqing Group) and 99Ca/320 (Dowex) resins were optimized, resulting in an optimal separation temperature and mobile phase flow rate of 70 °C, 10 ml/min. On this basis, a single-column chromatographic model was used to calculate the TD model parameter (N) and the mass transfer coefficient (km ) of the separation of erythritol mother liquor by DTF-01Ca (Suqing Group) and 99Ca/320 (Dowex) resins. The adsorption isotherms, TD model parameter (N) and the mass transfer coefficient (km ) provides data references for the design and operation of the simulated moving beds (SMB) separation system for the industrial-scale separation of erythritol crystallizing mother liquor.

2.
Crit Rev Food Sci Nutr ; : 1-21, 2023 Oct 04.
Artículo en Inglés | MEDLINE | ID: mdl-37791716

RESUMEN

Erythritol is a four-carbon sugar alcohol naturally produced by microorganisms as an osmoprotectant. As a new sugar substitute, erythritol has recently been popular on the ingredient market because of its unique nutritional characteristics. Even though the history of erythritol biosynthesis dates from the turn of the twentieth century, scientific advancement has lagged behind other polyols due to the relative complexity of making it. In recent years, biosynthetic methods for erythritol have been rapidly developed due to an increase in market demand, a better understanding of metabolic pathways, and the rapid development of genetic engineering tools. This paper reviews the history of industrial strain development and focuses on the underlying mechanism of high erythritol production by strains gained through screening or mutagenesis. Meanwhile, we highlight the metabolic pathway knowledge of erythritol biosynthesis in microorganisms and summarize the metabolic engineering and research progress on critical genes involved in different stages of the synthetic pathway. Lastly, we talk about the still-contentious issues and promising future research directions that will help break the erythritol production bottleneck and make erythritol production greener and more sustainable.

3.
Microb Cell Fact ; 22(1): 165, 2023 Aug 29.
Artículo en Inglés | MEDLINE | ID: mdl-37644496

RESUMEN

3-Hydroxybutanone (Acetoin, AC) and 2,3-butanediol (BD) are two essential four-carbon platform compounds with numerous pharmaceutical and chemical synthesis applications. AC and BD have two and three stereoisomers, respectively, while the application of the single isomer product in chemical synthesis is superior. AC and BD are glucose overflow metabolites produced by biological fermentation from a variety of microorganisms. However, the AC or BD produced by microorganisms using glucose is typically a mixture of various stereoisomers. This was discovered to be due to the simultaneous presence of multiple butanediol dehydrogenases (BDHs) in microorganisms, and AC and BD can be interconverted under BDH catalysis. In this paper, beginning with the synthesis pathways of microbial AC and BD, we review in detail the studies on the formation mechanisms of different stereoisomers of AC and BD, summarize the properties of different types of BDH that have been tabulated, and analyze the structural characteristics and affinities of different types of BDH by comparing them using literature and biological database data. Using microorganisms, recent research on the production of optically pure AC or BD was also reviewed. Limiting factors and possible solutions for chiral AC and BD production are discussed.


Asunto(s)
Acetoína , Butileno Glicoles , Especificidad por Sustrato , Glucosa
4.
Biosci Biotechnol Biochem ; 87(5): 541-554, 2023 Apr 24.
Artículo en Inglés | MEDLINE | ID: mdl-36807405

RESUMEN

Longgang soy sauce is one of the traditional fermented condiments in China, but its bacterial community succession and its unique flavor development during the fermentation process are not well-investigated. This study evaluated the bacterial diversity, flavor changes, and their correlation during the fermentation of Longgang soy sauce. The results showed that Weissella was the dominant bacterial genus in the fermentation stage of sauce fermented grains. In the first 31 days of the moromi fermentation stage, a variety of bacterial genera such as Weissella, Halomonas, Bacteroides, Pseudomonas, and Tetragenococcus were the dominant bacteria. Our results showed that these bacteria have a significantly positive correlation with phenylethyl alcohol, ethyl acetate, and 3-methyl-1-butanol. As the fermentation progressed, a flora structure with Halomonas as the main bacterial genus was formed. This genus exhibited a significantly positive and positive correlation with 1-octanol, ethyl palmitate, heptanol, and 2-nonanol, which are the unique flavor components of Longgang soy sauce.


Asunto(s)
Alcohol Feniletílico , Alimentos de Soja , Alimentos de Soja/microbiología , Bacterias , China , Fermentación
5.
Lett Appl Microbiol ; 76(7)2023 Jul 03.
Artículo en Inglés | MEDLINE | ID: mdl-37336586

RESUMEN

One thermotolerant Bacillus strain SFLV-ZM107 which could produce large amounts of extracellular polysaccharides (EPS) at 50°C was identified as Bacillus licheniformis by 16S rDNA sequencing and physiological and biochemical experiments. The EPS was identified as levan fructan by monosaccharides determination, NMR, and FTIR. Strain SFLV-ZM107 can be grown in the range of 35-55°C and it is efficient to produce levan from 400 to 500 g l-1 of sucrose. The production of levan can reach 158 g l-1 in a 5 L tank fermentation with an initial sucrose concentration of 450 g l-1 at 50°C for 12 hours with a maximum productivity of 13.17 g l-1 h-1. To the best of our knowledge, the strains obtained in this study are the most productive and efficient, which has great prospects for industrial application.


Asunto(s)
Bacillus licheniformis , Bacillus , Bacillus/genética , Bacillus/metabolismo , Fructanos/química , Bacillus licheniformis/metabolismo , Fermentación , Sacarosa , Polisacáridos Bacterianos/química
6.
Prep Biochem Biotechnol ; 53(1): 81-92, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-35289738

RESUMEN

Docosahexaenoic acid (DHA) has numerous functions in adjusting the organic health and pragmatic value in medicine and food field. In this study, we compared glycerol and glucose as the only carbon source for DHA production by Aurantiochytrium. When the glycerol concentration was 120 g/L, the maximum DHA yield was 11.08 g/L, and the DHA yield increased significantly, reaching 47.67% of the total lipid content. When the cells grew in glucose, the DHA proportion was 37.39%. Transcriptome data showed that the glycolysis pathway and tricarboxylic acid cycle in Aurantiochytrium were significantly inhibited during glycerol culture, which promoted the tricarboxylic acid transport system and was conducive to the synthesis of fatty acids by acetyl coenzyme A; glucose as substrate activated fatty acid synthesis (FAS)pathway and produced more saturated fatty acids, while glycerol as substrate activated polyketide synthase (PKS)pathway and produced more long-chain polyunsaturated fatty acids. This laid a foundation for fermentation metabolism regulation and molecular transformation.


Asunto(s)
Glicerol , Estramenopilos , Glicerol/metabolismo , Ácidos Docosahexaenoicos/metabolismo , Ácidos Docosahexaenoicos/farmacología , Glucosa/metabolismo , Fermentación , Ácidos Grasos/química , Perfilación de la Expresión Génica , Estramenopilos/genética , Estramenopilos/metabolismo
7.
Biosci Biotechnol Biochem ; 86(11): 1581-1589, 2022 Oct 20.
Artículo en Inglés | MEDLINE | ID: mdl-35998319

RESUMEN

The relationship between volatile compounds of vinegar and microorganisms is not clear, especially pyrazine, a trace component. In order to reveal their potential relationship, high throughput sequencing, solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) and Spearman's correlation analysis were used. Results showed that Acetobacter and Lactobacillus with opposite abundance trends were the predominant bacteria, and the total abundance of them exceeds 98%, while the predominant fungal genera were Aspergillus and Malassezia, their highest abundances are 75.4% and 81.5%, respectively. In the whole process of microbial community succession, 6 pyrazines were detected including trimethylpyrazine and tetramethylpyrazine, etc., and Spearman's correlation analysis showed that they were positively correlated with the presence of Vibrionimonas, Paraburkholderia, Paucibacter, Komagataeibacter, Acinetobacter, and Slinibacter. In general, this study further revealed more species related to pyrazines, it will be helpful to understand the formation of pyrazines and promote the improvement of vinegar quality.


Asunto(s)
Ácido Acético , Microbiota , Fermentación , Cromatografía de Gases y Espectrometría de Masas/métodos , Pirazinas
8.
Appl Microbiol Biotechnol ; 103(5): 2181-2192, 2019 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-30656392

RESUMEN

Itaconic acid, a promising platform chemical, has been applied in many fields of industrial production. As a potential candidate for itaconic acid production, Yarrowia lipolytica possesses several innate abilities such as the tolerance of low-pH and high-shear stress, fast growth rate, cultivation flexibility, and easy for genetic manipulation. Here, Y. lipolytica Po1f which was tested to show high tolerance to itaconic acid could accumulate itaconic acid (0.363 g/L) by expressing the Aspergillus terreus cis-aconitic acid decarboxylase (CAD). Then, we tried to improve the supply and transport of the immediate precursor cis-aconitic acid by overexpressing a series of genes; these results indicate that overexpression of mitochondrial cis-aconitate transporter MTT is beneficial to the itaconic acid biosynthesis in Y. lipolytica. Further culture optimization enabled 22.03 g/L of itaconic acid to be produced in bioreactors, about 60-fold improvement over the initial titer, which is the highest itaconic acid production achieved at low pH by yeast reported worldwide, to data. This study demonstrates the great potential of Y. lipolytica as an industrial platform for itaconic acid production.


Asunto(s)
Reactores Biológicos/microbiología , Proteínas de Transporte de Membrana/metabolismo , Mitocondrias/metabolismo , Succinatos/metabolismo , Yarrowia/genética , Yarrowia/metabolismo , Ácido Aconítico/metabolismo , Aspergillus/genética , Carboxiliasas/genética , Fermentación , Proteínas de Transporte de Membrana/genética
9.
Prep Biochem Biotechnol ; 47(8): 761-767, 2017 Sep 14.
Artículo en Inglés | MEDLINE | ID: mdl-28426331

RESUMEN

The present work aims to block 2,3-butanediol synthesis in acetoin fermentation of Bacillus subtilis. First, we constructed a recombinant strain BS168D by deleting the 2,3-butanediol dehydrogenase gene bdhA of the B. subtilis168, and there was almost no 2,3-butanediol production in 20 g/L of glucose media. The acetoin yield of BS168D reached 6.61 g/L, which was about 1.5 times higher than that of the control B. subtilis168 (4.47 g/L). Then, when the glucose concentration was increased to 100 g/L, the acetoin yield reached 24.6 g/L, but 2.4 g/L of 2,3-butanediol was detected at the end of fermentation. The analysis of 2,3-butanediol chiral structure indicated that the main 2,3-butanediol production of BS168D was meso-2,3-butanediol, and the bdhA gene was only responsible for (2R,3R)-2,3-butanediol synthesis. Therefore, we speculated that there may exit another pathway relating to the meso-2,3-butanediol synthesis in the B. subtilis. In addition, the results of low oxygen condition fermentation showed that deletion of bdhA gene successfully blocked the reversible transformation between acetoin and 2,3-butanediol and eliminated the effect of dissolved oxygen on the transformation.


Asunto(s)
Acetoína/metabolismo , Oxidorreductasas de Alcohol/genética , Bacillus subtilis/enzimología , Bacillus subtilis/genética , Butileno Glicoles/metabolismo , Eliminación de Gen , Oxidorreductasas de Alcohol/metabolismo , Bacillus subtilis/metabolismo , Fermentación , Ingeniería Metabólica
10.
Prep Biochem Biotechnol ; 44(5): 529-43, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24328672

RESUMEN

To improve the acetoin-producing ability of Bacillus subtilis SF4-3, isolated from "natto," a Japanese traditional food, the fermentation medium was optimized in shake-flask fermentation by statistically designed methods. Based on results of the single-factor experiment, orthogonal experiment, and Plackett-Burman design, yeast extract, corn steep liquor, and urea were identified as showing significant influence on the acetoin production. Subsequently, the optimum combination of the three factors was investigated by the Box-Behnken design (BBD) of response surface methodology (RSM) in order to further enhance the acetoin production. The maximum acetoin yield of 45.4 g/L was predicted when the concentrations of yeast extract, corn steep liquor, and urea were 8.5 g/L, 14.6 g/L, and 3.8 g/L, respectively. The results were further confirmed in triplicate experiments using the optimized medium (glucose 160 g/L, yeast extract 8.5 g/L, corn steep liquor 14.6 g/L, urea 3.8 g/L, manganese sulfate 0.05 g/L, ferrous sulfate 0.05 g/L), and an acetoin yield of 46.2 g/L was obtained in the validation experiment, which was in agreement with the prediction. After the optimization of medium components, an increase of 36.28% in acetoin production was achieved in comparison to that at the initial medium levels.


Asunto(s)
Acetoína/metabolismo , Bacillus subtilis/fisiología , Fermentación , Microbiología Industrial/métodos , Medios de Cultivo/metabolismo , Modelos Estadísticos
11.
Polymers (Basel) ; 16(14)2024 Jul 10.
Artículo en Inglés | MEDLINE | ID: mdl-39065294

RESUMEN

Pectin is widely used in the food and pharmaceutical industries. However, data on sweet potato pectin extraction and structural property analyses are lacking. Here, for the high-value utilization of agricultural processing waste, sweet potato residue, a byproduct of sweet potato starch processing, was used as raw material. Ammonium oxalate, trisodium citrate, disodium hydrogen phosphate, hydrochloric acid and citric acid were used as extractants for the pectin constituents, among which ammonium oxalate had a high extraction rate of sweet potato pectin, low ash content and high molecular weight. Structural and gelation analyses were conducted on ammonium oxalate-extracted purified sweet potato pectin (AMOP). Analyses showed that AMOP is a rhamnogalacturonan-I-type pectin, with a molecular weight of 192.5 kg/mol. Chemical titration and infrared spectroscopy analysis confirmed that AMOP is a low-ester pectin, and scanning electron and atomic force microscopy demonstrated its linear molecular structure. Gelation studies have revealed that Ca2+ is the key factor for gel formation, and that sucrose significantly enhanced gel hardness. The highest AMOP gel hardness was observed at pH 4, with a Ca2+ concentration of 30 mg/g, pectin concentration of 2%, and sucrose concentration of 40%, reaching 128.87 g. These results provide a foundation for sweet potato pectin production and applications.

12.
Prep Biochem Biotechnol ; 43(6): 551-64, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23742087

RESUMEN

In this study, Bacillus strains with an ability to produce acetoin were isolated from a Japanese traditional food, natto, on the basis of the Voges-Proskauer (VP) reaction, and strain SF4-3 was shown to be a predominant strain in acetoin production. Based on a variety of morphological, physiological, and biochemical characteristics as well as the nucleotide sequence analysis of 16S rDNA, the strain SF4-3 was identified as Bacillus subtilis. When it was incubated at 37°C with a speed of 180 rpm for 96 hr in the flasks, the maximum acetoin concentration was up to 33.90 g/L. The fermentation broths were determined by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) analyses; the results showed that the major metabolite was acetoin, and the purity could reach more than 95% without butanedione and 2,3-butanediol, which were usually produced together with acetoin in other strains. A novel aqueous two-phase system (ATPS) composed of hydrophilic solvents and inorganic salts was developed for the extraction of acetoin from fermentation broths. The ethanol and dipotassium hydrogen phosphate system could be used to extract acetoin from fermentation broths. The influences of phase composition on partition of acetoin were investigated. The maximum partition coefficient (9.68) and recovery (94.6%) of acetoin were obtained, when 25% (w/w) dipotassium hydrogen phosphate and 24% (w/w) ethanol were used.


Asunto(s)
Acetoína/aislamiento & purificación , Acetoína/metabolismo , Bacillus subtilis/aislamiento & purificación , Bacillus subtilis/metabolismo , Alimentos de Soja/microbiología , Bacillus subtilis/genética , Bacillus subtilis/fisiología , Medios de Cultivo/química , ADN Ribosómico , Etanol/química , Fermentación , Microbiología de Alimentos , Cromatografía de Gases y Espectrometría de Masas , Japón , Extracción Líquido-Líquido/métodos , Fosfatos/química , Filogenia , Compuestos de Potasio/química
13.
Artículo en Inglés | MEDLINE | ID: mdl-35270614

RESUMEN

This study aims to understand the research status and development trend of crisis and risk communication research (CRCR) through a visual analysis in CiteSpace, thereby providing a more comprehensive perspective for future research agenda. First, we retrieved published papers from Web of Science (1986-2020) and Scopus (1979-2020) with a title search. Subsequently, we analyzed the main research strengths and main topics of CRCR from two dimensions: co-authorship network and co-citation network. We conducted an in-depth co-citation network analysis from four perspectives: cluster analysis, high co-cited literature analysis, burst analysis, and turning points analysis. These results revealed the main research topics in the CRCR field, the most eye-catching research literature, the emerging research hotspots in each period, and the turning points of the overall development. Finally, we suggested further research directions for future avenues.


Asunto(s)
Bibliometría , Comunicación Interdisciplinaria , Análisis por Conglomerados , Publicaciones
14.
Electron. j. biotechnol ; 19(1): 41-49, Jan. 2016. ilus
Artículo en Inglés | LILACS | ID: lil-781169

RESUMEN

Background: Currently, microbial fermentation method has become the research hotspot for acetoin production. In our previous work, an acetoin-producing strain, Bacillus subtilis SF4-3, was isolated from Japanese traditional fermented food natto. However, its conversion of glucose to acetoin was relatively low. In order to achieve a high-efficient accumulation of acetoin in B. subtilis SF4-3, main medium components and fermentation conditions were evaluated in this work. Results: The by-products analysis showed that there existed reversible transformation between acetoin and 2,3-butanediol that was strictly responsible for acetoin production in B. subtilis SF4-3. The carbon sources, nitrogen sources and agitation speed were determined to play crucial role in the acetoin production. The optimal media (glucose-H2O 150 g/L, yeast extract 10 g/L, corn steep dry 5 g/L, urea 2 g/L, K2HPO4 0.5 g/L, MgSO4 0.5 g/L) were obtained. Furthermore, the low agitation speed of 300 r/min was found to be beneficial to the reversible transformation of 2,3-butanediol for acetoin production in B. subtilis SF4-3. Eventually, 48.9 g/L of acetoin and 5.5 g/L of 2,3-butanediol were obtained in a 5-L fermenter, and the specific production of acetoin was 39.12% (g/g), which accounted for 79.90% of the theoretical conversion. Conclusions: The results indicated acetoin production of B. subtilis SF4-3 was closely related to the medium components and dissolved oxygen concentrations. It also provided a method for acetoin production via the reversible transformation of acetoin and 2,3-butanediol.


Asunto(s)
Bacillus subtilis , Acetoína/metabolismo , Butileno Glicoles , Técnicas de Cultivo , Fermentación , Glucosa , Nitrógeno
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA