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1.
An Acad Bras Cienc ; 93(1): e20190672, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33825790

RESUMEN

Lipases are hydrolases used in various sectors such as the food, pharmaceutical and chemical synthesis industries. In this study, epiphytic microorganisms were isolated from the Serra of Ouro Branco State Park (Minas Gerais, Brazil) and were subsequently evaluated for their ability to produce extracellular lipases. Among the 46 isolated strains, 25 presented positive results for lipase production in the agar plate screening assay. Two of these strains that expressed the highest diffusion halos, were genetically identified as Serratia marcescens and Pseudomonas fluorescens and catalogued in the Tropical Cultures Collection from the André Tosello Foundation/Brazil as CCT 7796 and CCT 7797, respectively. The fermentation growth kinetics indicated that the maximum extracellular lipase activities were achieved between 96 and 120h of cultivation. The highest lipolytic activity for both strains was observed at an optimum temperature and pH of 37°C and 7.0, respectively. At these conditions, the lipase activity detected in the crude enzymatic extract of both strains was close to 15.0 U/mL. We consider that these species are promising lipase producers for industrial applications.


Asunto(s)
Lipasa , Lipólisis , Brasil , Fermentación , Concentración de Iones de Hidrógeno , Cinética , Temperatura
2.
Nat Commun ; 12(1): 1498, 2021 03 08.
Artículo en Inglés | MEDLINE | ID: mdl-33686084

RESUMEN

Sugarcane ethanol fermentation represents a simple microbial community dominated by S. cerevisiae and co-occurring bacteria with a clearly defined functionality. In this study, we dissect the microbial interactions in sugarcane ethanol fermentation by combinatorically reconstituting every possible combination of species, comprising approximately 80% of the biodiversity in terms of relative abundance. Functional landscape analysis shows that higher-order interactions counterbalance the negative effect of pairwise interactions on ethanol yield. In addition, we find that Lactobacillus amylovorus improves the yeast growth rate and ethanol yield by cross-feeding acetaldehyde, as shown by flux balance analysis and laboratory experiments. Our results suggest that Lactobacillus amylovorus could be considered a beneficial bacterium with the potential to improve sugarcane ethanol fermentation yields by almost 3%. These data highlight the biotechnological importance of comprehensively studying microbial communities and could be extended to other microbial systems with relevance to human health and the environment.


Asunto(s)
Fenómenos Fisiológicos Bacterianos , Etanol/metabolismo , Fermentación , Interacciones Microbianas/fisiología , Saccharomyces cerevisiae/fisiología , Acetaldehído/metabolismo , Acetaldehído/farmacología , Bacterias/clasificación , Bacterias/crecimiento & desarrollo , Biodiversidad , Microbiología Industrial/métodos , Lactobacillus/metabolismo , Microbiota , Melaza , Saccharomyces cerevisiae/efectos de los fármacos , Saccharum
4.
Sheng Wu Gong Cheng Xue Bao ; 37(2): 384-394, 2021 Feb 25.
Artículo en Chino | MEDLINE | ID: mdl-33645142

RESUMEN

Polyhydroxyalkanoates (PHAs) are polymers obtained by esterification of hydroxy fatty acid monomers. Due to similar mechanical characteristics of traditional petroleum-based plastics, 100% biodegradability and biocompatibility, PHAs are considered to be one of the most potential green materials. However, the application and promotion of PHAs as a green and environmentally friendly material are difficult because of the high production costs. This article focuses on the current methods to reduce production cost of PHAs effectively, such as cell morphology regulation, metabolic pathway construction, economic carbon source utilization and open fermentation technology development. Despite most research results are still limited in laboratory, the research methods and directions provide theoretical guidance for the industrial production of economic PHAs.


Asunto(s)
Petróleo , Polihidroxialcanoatos , Fermentación , Industrias , Plásticos
5.
Sheng Wu Gong Cheng Xue Bao ; 37(2): 429-447, 2021 Feb 25.
Artículo en Chino | MEDLINE | ID: mdl-33645146

RESUMEN

Higher alcohols are one of the main by-products of Saccharomyces cerevisiae in brewing. High concentration of higher alcohols in alcoholic beverages easily causes headache, thirst and other symptoms after drinking. It is also the main reason for chronic drunkenness and difficulty in sobering up after intoxication. The main objective of this review is to present an overview of the flavor characteristics and metabolic pathways of higher alcohols as well as the application of mutagenesis breeding techniques in the regulation of higher alcohol metabolism in S. cerevisiae. In particular, we review the application of metabolic engineering technology in genetic modification of amino transferase, α-keto acid metabolism, acetate metabolism and carbon-nitrogen metabolism. Moreover, key challenges and future perspectives of realizing optimization of higher alcohols metabolism are discussed. This review is intended to provide a comprehensive understanding of metabolic regulation system of higher alcohols in S. cerevisiae and to provide insights into the rational development of the excellent industrial S. cerevisiae strains producing higher alcohols.


Asunto(s)
Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae , Bebidas Alcohólicas , Alcoholes/análisis , Fermentación , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo
6.
Sheng Wu Gong Cheng Xue Bao ; 37(2): 448-460, 2021 Feb 25.
Artículo en Chino | MEDLINE | ID: mdl-33645147

RESUMEN

Resource utilization is an effective way to cope with the rapid increase of kitchen waste and excess sludge, and volatile fatty acids produced by anaerobic fermentation is an important way of recycling organic waste. However, the single substrate limits the efficient production of volatile fatty acids. In recent years, volatile fatty acids produced by anaerobic co-fermentation using different substrates has been widely studied and applied. In this paper, we analyze the characteristics of fermentation to produce acid using kitchen waste and excess sludge alone or mixture. Influences of environmental factors and microbial community structure on the type and yield of volatile fatty acids in the anaerobic fermentation system are discussed in detail. Moreover, we propose future research directions, to provide a reference for recycling kitchen waste and excess sludge.


Asunto(s)
Microbiota , Aguas del Alcantarillado , Anaerobiosis , Reactores Biológicos , Ácidos Grasos Volátiles , Fermentación , Concentración de Iones de Hidrógeno , Compuestos Orgánicos
7.
Sheng Wu Gong Cheng Xue Bao ; 37(2): 473-485, 2021 Feb 25.
Artículo en Chino | MEDLINE | ID: mdl-33645149

RESUMEN

Lignocellulose is the most abundant renewable organic carbon resource on earth. However, due to its complex structure, it must undergo a series of pretreatment processes before it can be efficiently utilized by microorganisms. The pretreatment process inevitably generates typical inhibitors such as furan aldehydes that seriously hinder the growth of microorganisms and the subsequent fermentation process. It is an important research field for bio-refining to recognize and clarify the furan aldehydes metabolic pathway of microorganisms and further develop microbial strains with strong tolerance and transformation ability towards these inhibitors. This article reviews the sources of furan aldehyde inhibitors, the inhibition mechanism of furan aldehydes on microorganisms, the furan aldehydes degradation pathways in microorganisms, and particularly focuses on the research progress of using biotechnological strategies to degrade furan aldehyde inhibitors. The main technical methods include traditional adaptive evolution engineering and metabolic engineering, and the emerging microbial co-cultivation systems as well as functional materials assisted microorganisms to remove furan aldehydes.


Asunto(s)
Aldehídos , Lignina , Fermentación , Furanos , Lignina/metabolismo
8.
Sheng Wu Gong Cheng Xue Bao ; 37(2): 689-695, 2021 Feb 25.
Artículo en Chino | MEDLINE | ID: mdl-33645167

RESUMEN

Fermentation engineering is an industrial process that uses the transformation of microorganisms or other cells to produce a specific product in a specific bioreactor. Fermentation engineering has developed from an ancient food fermentation relying solely on experience accumulation to an important production mode of food, agriculture, medicine, chemical industry and other means of production and life. It has become a key technology to support the sustainable development of human beings, and is inseparable from the continuous progress of interdisciplinary technology. The interdisciplinary integration and the continuous upward movement of China's global industrial chain will inevitably put forward higher requirements for the cultivation of fermentation engineering composite talents in the new situation. In order to constantly improve the interdisciplinary fermentation engineering compound talent training system, in recent years, the research lab has been refining and improving the concept of talent training, and actively deepening the reform of talent training system. Systematic research and practice have been carried out around the aspects of training program, enrollment system, teacher background, subject setting, scientific research practice, evaluation system, etc., which has promoted the technological progress of fermentation engineering and related supporting industries, and contributed an important force to the transformation of China from a big fermentation country to a powerful fermentation country.


Asunto(s)
Agricultura , Industrias , China , Fermentación , Humanos
9.
Nat Commun ; 12(1): 1389, 2021 03 02.
Artículo en Inglés | MEDLINE | ID: mdl-33654100

RESUMEN

Sulfated glycosaminoglycans (GAGs) are a class of important biologics that are currently manufactured by extraction from animal tissues. Although such methods are unsustainable and prone to contamination, animal-free production methods have not emerged as competitive alternatives due to complexities in scale-up, requirement for multiple stages and cost of co-factors and purification. Here, we demonstrate the development of single microbial cell factories capable of complete, one-step biosynthesis of chondroitin sulfate (CS), a type of GAG. We engineer E. coli to produce all three required components for CS production-chondroitin, sulfate donor and sulfotransferase. In this way, we achieve intracellular CS production of ~27 µg/g dry-cell-weight with about 96% of the disaccharides sulfated. We further explore four different factors that can affect the sulfation levels of this microbial product. Overall, this is a demonstration of simple, one-step microbial production of a sulfated GAG and marks an important step in the animal-free production of these molecules.


Asunto(s)
Vías Biosintéticas , Sulfatos de Condroitina/biosíntesis , Escherichia coli/metabolismo , Transporte Biológico , Escherichia coli/enzimología , Fermentación , Oxidorreductasas/metabolismo , Sulfotransferasas/metabolismo
10.
Waste Manag ; 124: 339-347, 2021 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-33662765

RESUMEN

The surfactant-assisted thermal hydrolysis pretreatment (THP) of waste activated sludge (WAS) was investigated, focusing on the effect of the surfactant addition on the results of sludge disintegration, dewaterability, organic release, and production of volatile fatty acids (VFAs) via fermentation. Typical anionic surfactant sodium dodecyl sulfate (SDS) and cationic surfactant cetyl trimethyl ammonium bromide (CTAB) were used for the THP experiments. The supernatant of the THP-treated sludge was anaerobically fermented to determine its potential VFAs yield. The results showed that the surfactant addition, particularly CTAB, enhanced the hydrolysis and organic solubilization of the sludge during THP. CTAB addition led to a 36% increase of dissolved organic and a 27% increase of VFAs production. For the THP-treated sludge with the surfactant addition, its dewaterability was also greatly improved. When the CTAB dosage increased from 0 to 0.10 g/g VSS, the minimum capillary suction time (CST) of the sludge decreased from 205 to 50 s/g TSS, and the sludge particles became smaller and less negative with the zeta potential changing from -12.4 to -8.2 mV. Analysis of extracellular polymeric substances (EPS) of the sludge revealed that the surfactant addition increased the sludge disintegration and organic dissolution during the THP process. The surfactant-assisted THP is shown to be a promising technology to enhance the WAS treatment for improved sludge dewaterability, waste reduction, and resource recovery.


Asunto(s)
Aguas del Alcantarillado , Tensoactivos , Ácidos Grasos Volátiles , Fermentación , Hidrólisis , Eliminación de Residuos Líquidos
11.
Methods Mol Biol ; 2278: 209-223, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33649959

RESUMEN

Bifidogenic effect is a main target for the assessment of prebiotic activity. pH-controlled batch processes of bifidobacteria and fecal microbiota are herein presented. Growth of bifidobacteria, carbohydrate breakdown and consumption, organic acid production, and activity of specific glycosyl hydrolases involved in the hydrolysis of di-, oligo-, or polysaccharides are exploited to study and compare substrate preference of bifidobacteria for candidate prebiotics.


Asunto(s)
Bifidobacterium/metabolismo , Polisacáridos Bacterianos/metabolismo , Proteínas Bacterianas/metabolismo , Técnicas de Cultivo Celular por Lotes/métodos , Bifidobacterium/química , Bifidobacterium/crecimiento & desarrollo , Reactores Biológicos , Metabolismo de los Hidratos de Carbono , Cromatografía Líquida de Alta Presión/métodos , Cromatografía por Intercambio Iónico/métodos , Cromatografía en Capa Delgada/métodos , Pruebas de Enzimas/métodos , Fermentación , Microbioma Gastrointestinal , Humanos , Hidrolasas/metabolismo , Hidrólisis , Polisacáridos Bacterianos/análisis
12.
Food Chem ; 352: 129350, 2021 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-33657481

RESUMEN

Fermented cassava products are important starchy food staples in South America. The quality of the products is affected by the baking expansion ability of the dough, which is in turn influenced by the starch fermentation process and drying method employed. We investigated the structural properties of cassava starch after different fermentation and drying treatments, and the effect of starch structure on scalding of dough and baking expansion ability. Fermentation combined with either exposure to sunlight or UV light treatment resulted in high cassava starch baking expansion. Moreover, we observed decreased crystallinity and increased disordered crystalline regions with lower molecular weight in the two types of starch-fermented combined with sunlight or UV light treatment-and both appeared to have a continuous network structure and polarized cross in scalded dough, which are conducive to holding gas and losing water, thus promoting high baking expansibility.


Asunto(s)
Manipulación de Alimentos , Manihot/química , Almidón/química , Desecación , Fermentación , Manihot/efectos de la radiación , Peso Molecular , Luz Solar , Rayos Ultravioleta
13.
Molecules ; 26(5)2021 Feb 25.
Artículo en Inglés | MEDLINE | ID: mdl-33669129

RESUMEN

Often blamed for bringing green aromas and astringency to wines, the use of stems is also empirically known to improve the aromatic complexity and freshness of some wines. Although applied in different wine-growing regions, stems use remains mainly experimental at a cellar level. Few studies have specifically focused on the compounds extracted from stems during fermentation and maceration and their potential impact on the must and wine matrices. We identified current knowledge on stem chemical composition and inventoried the compounds likely to be released during maceration to consider their theoretical impact. In addition, we investigated existing studies that examined the impact of either single stems or whole clusters on the wine quality. Many parameters influence stems' effect on the wine, especially grape variety, stem state, how stems are incorporated, when they are added, and contact duration. Other rarely considered factors may also have an impact, including vintage and ripening conditions, which could affect the lignification of the stem.


Asunto(s)
Calidad de los Alimentos , Tallos de la Planta/química , Polifenoles/análisis , Vitis/química , Vino/análisis , Vino/normas , Fermentación , Tallos de la Planta/metabolismo , Polifenoles/metabolismo , Vitis/metabolismo
14.
Molecules ; 26(4)2021 Feb 16.
Artículo en Inglés | MEDLINE | ID: mdl-33669237

RESUMEN

Yeast plays a key role in the production of fermented foods and beverages, such as bread, wine, and other alcoholic beverages. They are able to produce and release from the fermentation environment large numbers of volatile organic compounds (VOCs). This is the reason for the great interest in the possibility of adapting these microorganisms to fermentation at reduced temperatures. By doing this, it would be possible to obtain better sensory profiles of the final products. It can reduce the addition of artificial flavors and enhancements to food products and influence other important factors of fermented food production. Here, we reviewed the genetic and physiological mechanisms by which yeasts adapt to low temperatures. Next, we discussed the importance of VOCs for the food industry, their biosynthesis, and the most common volatiles in fermented foods and described the beneficial impact of decreased temperature as a factor that contributes to improving the composition of the sensory profiles of fermented foods.


Asunto(s)
Adaptación Fisiológica , Frío , Ambiente , Fermentación , Saccharomyces cerevisiae/metabolismo , Compuestos Orgánicos Volátiles/metabolismo , Adaptación Fisiológica/genética , Fermentación/genética , Saccharomyces cerevisiae/genética
15.
Molecules ; 26(4)2021 Feb 11.
Artículo en Inglés | MEDLINE | ID: mdl-33670262

RESUMEN

Stingless bee-collected pollen (bee bread) is a mixture of bee pollen, bee salivary enzymes, and regurgitated honey, fermented by indigenous microbes during storage in the cerumen pot. Current literature data for bee bread is overshadowed by bee pollen, particularly of honeybee Apis. In regions such as South America, Australia, and Southeast Asia, information on stingless bee bee bread is mainly sought to promote the meliponiculture industry for socioeconomic development. This review aims to highlight the physicochemical properties and health benefits of bee bread from the stingless bee. In addition, it describes the current progress on identification of beneficial microbes associated with bee bread and its relation to the bee gut. This review provides the basis for promoting research on stingless bee bee bread, its nutrients, and microbes for application in the food and pharmaceutical industries.


Asunto(s)
Abejas/química , Miel , Própolis/química , Glándulas Salivales/química , Animales , Australia , Abejas/metabolismo , Fermentación , Polen/química , Própolis/uso terapéutico , Glándulas Salivales/metabolismo , América del Sur
16.
Molecules ; 26(4)2021 Feb 23.
Artículo en Inglés | MEDLINE | ID: mdl-33672299

RESUMEN

This study presents the effect of the application of high-power ultrasound to crushed grapes, at a winery-scale, on the content of varietal volatile compounds (free and glycosidically-bound) in musts and on the overall aroma of wines. Two different frequencies (20 kHz and 28 kHz) were tested and the combination of grape sonication and different maceration times on wine aroma was also evaluated. The volatile compounds were isolated by solid phase extraction and analyzed by gas chromatography-mass spectrometry, carrying out a sensory evaluation of wines by quantitative descriptive analysis. Sonication produced an increase in the concentration of free varietal compounds such as C6 alcohols, terpenes and norisoprenoids in musts and also in wines made by 48 h of skin maceration, being less efficient in the extraction of the bound fraction. Fermentation compounds were also positively affected by ultrasound treatment, although this effect was variable depending on the frequency used, the maceration time and the type of compound. All the wines made from sonicated grapes had better scores in the evaluated olfactory attributes with respect to the control wines. Our results indicate that sonication could produce an increase in the content of some volatile compounds of sensory relevance, obtaining wines with an aroma quality similar or higher than those elaborated with longer maceration times.


Asunto(s)
Glicósidos/análisis , Compuestos Orgánicos Volátiles/análisis , Vino/análisis , Fermentación , Cromatografía de Gases y Espectrometría de Masas , Glicósidos/metabolismo , Ondas Ultrasónicas , Compuestos Orgánicos Volátiles/metabolismo
17.
Nat Commun ; 12(1): 1411, 2021 03 03.
Artículo en Inglés | MEDLINE | ID: mdl-33658500

RESUMEN

Genetically programmed circuits allowing bifunctional dynamic regulation of enzyme expression have far-reaching significances for various bio-manufactural purposes. However, building a bio-switch with a post log-phase response and reversibility during scale-up bioprocesses is still a challenge in metabolic engineering due to the lack of robustness. Here, we report a robust thermosensitive bio-switch that enables stringent bidirectional control of gene expression over time and levels in living cells. Based on the bio-switch, we obtain tree ring-like colonies with spatially distributed patterns and transformer cells shifting among spherical-, rod- and fiber-shapes of the engineered Escherichia coli. Moreover, fed-batch fermentations of recombinant E. coli are conducted to obtain ordered assembly of tailor-made biopolymers polyhydroxyalkanoates including diblock- and random-copolymer, composed of 3-hydroxybutyrate and 4-hydroxybutyrate with controllable monomer molar fraction. This study demonstrates the possibility of well-organized, chemosynthesis-like block polymerization on a molecular scale by reprogrammed microbes, exemplifying the versatility of thermo-response control for various practical uses.


Asunto(s)
Escherichia coli/genética , Regulación Bacteriana de la Expresión Génica , Ingeniería Metabólica/métodos , Polihidroxialcanoatos/metabolismo , Ácido 3-Hidroxibutírico/metabolismo , Escherichia coli/crecimiento & desarrollo , Escherichia coli/metabolismo , Fermentación , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Hidroxibutiratos/metabolismo , Proteínas Luminiscentes/genética , Proteínas Luminiscentes/metabolismo , Microorganismos Modificados Genéticamente , Poliésteres/metabolismo , Temperatura , Imagen de Lapso de Tiempo
18.
Food Chem ; 351: 128454, 2021 Jul 30.
Artículo en Inglés | MEDLINE | ID: mdl-33652296

RESUMEN

This study aimed to elaborate the roles of salt concentration on doubanjiang (broad bean paste) fermentation. Three sets of doubanjiang samples which had lower salt concentration than commercial doubanjiang were prepared and the physicochemical parameters, biogenic amines, flavor, microbial dynamics were analyzed during fermentation. The salt reduction showed significant effect on the dynamics of bacteria and fungi, thus leading to doubanjiang samples with different properties. Salt reduction during fermentation relieved the osmotic pressure towards microbes, which favored the accumulation of amino acid nitrogen, amino acids, and volatile flavor compounds. However, higher concentrations of total acids and biogenic amines and the existence of conditional pathogens, such as Klebsiella, Cronobacter and Acinetobacter genera, were observed in salt reduced doubanjiang samples, which was undesirable for doubanjiang quality. This study would deep our understanding of the roles of salt on doubanjiang fermentation.


Asunto(s)
Fenómenos Químicos , Fermentación , Cloruro de Sodio Dietético/análisis , Alimentos de Soja/análisis , Alimentos de Soja/microbiología , Gusto , Aminoácidos/metabolismo , Bacterias/metabolismo , Aminas Biogénicas/metabolismo , Hongos/metabolismo
19.
Bioresour Technol ; 329: 124878, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33652190

RESUMEN

This study proposed a strategy to maximize the hydrogen yield by reusing feedstock of Arundo donax L. For this purpose, a successive 4-batch photo-fermentative hydrogen production (PFHP) was carried out to test the strategy. About 50% of total hydrogen yield was additionally obtained by reusing the Arundo donax L for successive 4 times in comparison to single 1st batch (161.4 mL/U. cell dry weight). In addition to the highest hydrogen yield, the maximum hydrogen production rate (6.0 mL/U. cell dry weight /h), and the highest volatile fatty acids (VFAs) concentration (32 mM) were also obtained from the 1st batch, while the 2nd batch gave the maximum substrate conversion efficiency (96.5%). Moreover, a positive relationship between the sum of acetic and butyric acids with hydrogen yields was observed. This strategy would help in enhancing hydrogen yield that coupled with cost reduction for biohydrogen production.


Asunto(s)
Hidrógeno , Poaceae , Ácidos Grasos Volátiles , Fermentación
20.
Bioresour Technol ; 329: 124910, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33677424

RESUMEN

Yarrowia lipolytica is an efficient oleaginous yeast, whereas its activity is typically reduced by inhibitors present in lignocellulosic hydrolysate. Understanding the response mechanism of Y. lipolytica to hydrolysate inhibitors and developing inhibitor tolerant strains are vital to lignocellulose valorization by this promising species. In this study, through adaptive laboratory evolution on three representative aromatic aldehyde inhibitors, evolved strains were obtained. Fermentation phenotype suggested that aromatic aldehydes conversion was one main reason for high tolerance of adapted strains. Transcriptome profiling analysis and reverse metabolic engineering confirmed that overexpressing the aldehyde ketone reductase gene YALI0_B07117g and aldehyde dehydrogenase gene YALI0_B01298g effectively converted aromatic aldehyde to corresponding alcohols and acids. The potential degradation pathways for aromatic aldehyde inhibitors in Y. lipolytica XYL+ were then discussed. This study provided insights to the aromatic aldehyde degradation in Y. lipolytica and a reliable basis for the development of aromatic aldehyde tolerant strains.


Asunto(s)
Yarrowia , Aldehídos , Fermentación , Ingeniería Metabólica , Transcriptoma/genética , Yarrowia/genética
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