RESUMO
Kluyveromyces marxianus is a non-Saccharomyces yeast that has gained importance due to its great potential to be used in the food and biotechnology industries. In general, K. marxianus is a known yeast for its ability to assimilate hexoses and pentoses; even this yeast can grow in disaccharides such as sucrose and lactose and polysaccharides such as agave fructans. Otherwise, K. marxianus is an excellent microorganism to produce metabolites of biotechnological interest, such as enzymes, ethanol, aroma compounds, organic acids, and single-cell proteins. However, several studies highlighted the metabolic trait variations among the K. marxianus strains, suggesting genetic diversity within the species that determines its metabolic functions; this diversity can be attributed to its high adaptation capacity against stressful environments. The outstanding metabolic characteristics of K. marxianus have motivated this yeast to be a study model to evaluate its easy adaptability to several environments. This chapter will discuss overview characteristics and applications of K. marxianus and recent insights into the stress response and adaptation mechanisms used by this non-Saccharomyces yeast.
Assuntos
Etanol , Kluyveromyces , Biotecnologia , Etanol/metabolismo , Fermentação , Kluyveromyces/genética , Kluyveromyces/metabolismoRESUMO
A bioassay containing Kluyveromyces marxianus in microtiter plates was used to determine the inhibitory action of 28 antibiotics (aminoglycosides, beta-lactams, macrolides, quinolones, tetracyclines and sulfonamides) against this yeast in whey. For this purpose, the dose-response curve for each antibiotic was constructed using 16 replicates of 12 different concentrations of the antibiotic. The plates were incubated at 40°C until the negative samples exhibited their indicator (5-7h). Subsequently, the absorbances of the yeast cells in each plate were measured by the turbidimetric method (λ=600nm) and the logistic regression model was applied. The concentrations causing 10% (IC10) and 50% (IC50) of growth inhibition of the yeast were calculated. The results allowed to conclude that whey contaminated with cephalosporins, quinolones and tetracyclines at levels close to the Maximum Residue Limits inhibits the growth of K. marxianus. Therefore, previous inactivation treatments should be implemented in order to re-use this contaminated whey by fermentation with K. marxianus.
Assuntos
Antibacterianos , Kluyveromyces , Soro do Leite , Kluyveromyces/efeitos dos fármacos , Antibacterianos/farmacologia , Testes de Sensibilidade Microbiana , Relação Dose-Resposta a DrogaRESUMO
We report the draft genomes of four Kluyveromyces marxianus isolates obtained from the elaboration process of henequen (Agave fourcroydes) mezcal, a Mexican alcoholic beverage. The average nucleotide identity analysis revealed that isolates derived from agave plants are distinct from those from other environments, including agave fermentations.
RESUMO
The management of inflammatory states typically involves non-steroidal anti-inflammatory drugs (NSAIDs) and opiates. Understanding the mechanisms underlying the processing of nociceptive information from potential alternatives such as some polysaccharides may enable new and meaningful therapeutic approaches. In this study, α-D-mannan isolated from the Kluyveromyces marxianus cell wall produced antinociceptive effects in models of inflammatory pain (formalin and complete Freund's adjuvant tests). Furthermore, α-D-mannan reduced paw edema and interleukin-6 (IL-6) production after carrageenan-induced inflammation. The polysaccharide α-D-mannan was characterized by gas chromatography-mass spectrometry, methylation analysis, and spectroscopic techniques. Moreover, the Doehlert experimental design was applied to find the optimal conditions for biomass production, with the best conditions being 10.8 g/L and 117 h for the glucose concentration and the fermentation time, respectively. These results indicate that α-D-mannan from K. marxianus exerts anti-inflammatory and antinociceptive effects in mice, possibly via a mechanism dependent on the inhibition of IL-6 production.
Assuntos
Analgésicos , Interleucina-6 , Camundongos , Animais , Analgésicos/farmacologia , Analgésicos/química , Analgésicos/uso terapêutico , Mananas , Anti-Inflamatórios/farmacologia , PolissacarídeosRESUMO
AIMS: The aims of this study were to evaluate the potential of Hanseniaspora opuntiae, Meyerozyma caribbica, and Kluyveromyces marxianus for in vitro biocontrol of Aspergillus ochraceus, A. westerdijkiae, and A. carbonarius growth, the ochratoxin A (OTA) effect on yeast growth, and yeast in vitro OTA detoxification ability using an experimental design to predict the combined effects of inoculum size, incubation time, and OTA concentration. METHODS AND RESULTS: Predictive models were developed using an incomplete Box-Behnken experimental design to predict the combined effects of inoculum size, incubation time, and OTA concentration on OTA detoxification by the yeasts. The yeasts were able to inhibit fungal growth from 13% to 86%. Kluyveromyces marxianus was the most efficient in inhibiting the three Aspergillus species. Furthermore, high OTA levels (100 ng ml-1) did not affect yeast growth over 72 h incubation. The models showed that the maximum OTA detoxification under optimum conditions was 86.8% (H. opuntiae), 79.3% (M. caribbica), and 73.7% (K. marxianus), with no significant difference (P > 0.05) between the values predicted and the results obtained experimentally. CONCLUSION: The yeasts showed potential for biocontrol of ochratoxigenic fungi and OTA detoxification, and the models developed are important tools for predicting the best conditions for the application of these yeasts as detoxification agents.
RESUMO
Seven Kluyveromyces marxianus isolates from the elaboration process of pulque and henequen mezcal were characterized. The isolates were identified based on the sequences of the D1/D2 domain of the 26S rRNA gene and the internal transcribed spacer (ITS-5.8S) region. Genetic differences were found between pulque and henequen mezcal isolates and within henequen mezcal isolates, as shown by different branching patterns in the ITS-5.8S phylogenetic tree and (GTG)5 microsatellite profiles, suggesting that the substrate and process selective conditions may give rise to different K. marxianus populations. All the isolates fermented and assimilated inulin and lactose and some henequen isolates could also assimilate xylose and cellobiose. Henequen isolates were more thermotolerant than pulque ones, which, in contrast, presented more tolerance to the cell wall-disturbing agent calcofluor white (CFW), suggesting that they had different cell wall structures. Additionally, depending on their origin, the isolates presented different maximum specific growth rate (µmax) patterns at different temperatures. Concerning tolerance to stress factors relevant for lignocellulosic hydrolysates fermentation, their tolerance limits were lower at 42 than 30 °C, except for glucose and furfural. Pulque isolates were less tolerant to ethanol, NaCl, and Cd. Finally, all the isolates could produce ethanol by simultaneous saccharification and fermentation (SSF) of a corncob hydrolysate under laboratory conditions at 42 °C.
RESUMO
This paper presents results concerning mechanistic modeling to describe the dynamics and interactions between biomass growth, glucose consumption and ethanol production in batch culture fermentation by Kluyveromyces marxianus (K. marxianus). The mathematical model was formulated based on the biological assumptions underlying each variable and is given by a set of three coupled nonlinear first-order Ordinary Differential Equations. The model has ten parameters, and their values were fitted from the experimental data of 17 K. marxianus strains by means of a computational algorithm design in Matlab. The latter allowed us to determine that seven of these parameters share the same value among all the strains, while three parameters concerning biomass maximum growth rate, and ethanol production due to biomass and glucose had specific values for each strain. These values are presented with their corresponding standard error and 95% confidence interval. The goodness of fit of our system was evaluated both qualitatively by in silico experimentation and quantitative by means of the coefficient of determination and the Akaike Information Criterion. Results regarding the fitting capabilities were compared with the classic model given by the logistic, Pirt, and Luedeking-Piret Equations. Further, nonlinear theories were applied to investigate local and global dynamics of the system, the Localization of Compact Invariant Sets Method was applied to determine the so-called localizing domain, i.e., lower and upper bounds for each variable; whilst Lyapunov's stability theories allowed to establish sufficient conditions to ensure asymptotic stability in the nonnegative octant, i.e., R+,03. Finally, the predictive ability of our mechanistic model was explored through several numerical simulations with expected results according to microbiology literature on batch fermentation.
RESUMO
Kluyveromyces marxianus is a non-conventional yeast with outstanding physiological characteristics and a high potential for lignocellulosic ethanol production. However, achieving high ethanol productivity requires overcoming several biotechnological challenges due to the cellular inhibition caused by the inhibitors present in the medium. In this work, K. marxianus SLP1 was adapted to increase its tolerance to a mix of inhibitory compounds using the adaptive laboratory evolution strategy to study the adaptation and stress response mechanisms used by this non-Saccharomyces yeast. The fermentative and physiological parameters demonstrated that the adapted K. marxianus P8 had a better response against the synergistic effects of multiple inhibitors because it reduced the lag phase from 12 to 4 h, increasing the biomass by 40% and improving the volumetric ethanol productivity 16-fold than the parental K. marxianus SLP1. To reveal the effect of adaptation process in P8, transcriptome analysis was carried out; the result showed that the basal gene expression in P8 changed, suggesting the biological capability of K. marxianus to activate the adaptative prediction mechanism. Similarly, we carried out physiologic and transcriptome analyses to reveal the mechanisms involved in the stress response triggered by furfural, the most potent inhibitor in K. marxianus. Stress response studies demonstrated that P8 had a better physiologic response than SLP1, since key genes related to furfural transformation (ALD4 and ALD6) and stress response (STL1) were upregulated. Our study demonstrates the rapid adaptability of K. marxianus to stressful environments, making this yeast a promising candidate to produce lignocellulosic ethanol. KEY POINTS: ⢠K. marxianus was adapted to increase its tolerance to a mix of inhibitory compounds ⢠The basal gene expression of K. marxianus changed after the adaptation process ⢠Adapted K. marxianus showed a better physiological response to stress by inhibitors ⢠Transcriptome analyses revealed key genes involved in the stress response.
Assuntos
Furaldeído , Kluyveromyces , Furaldeído/metabolismo , Kluyveromyces/genética , Kluyveromyces/metabolismo , Perfilação da Expressão Gênica , Fermentação , Etanol/metabolismoRESUMO
RESUMEN Introducción: Los productos naturales con actividad farmacológica requieren de evaluaciones preclínicas que justifiquen su empleo sobre una base científica. El ensayo de pirógenos es una prueba dentro de la Farmacología de Seguridad que se realiza para determinar la presencia de endotoxinas y constituye un método valioso, para demostrar la seguridad de bioderivados con potencial prebiótico en el campo de la inmunonutrición. Objetivo: Evaluar la pirogenicidad de bioproductos fúngicos de Pleurotus ostreatus (extractos acuosos del micelio y cuerpos fructíferos) y un biopreparado de levadura Kluyveromyces marxianus, empleando el ensayo de pirógenos en conejos Nueva Zelanda. Método: Se ensayaron concentraciones de 1,0 y 10,0 mg/mL de cada muestra por vía endovenosa en dosis de 0,5 y 5,0 mg/kg de peso. El diseño experimental cumplió las buenas prácticas de laboratorio según lo establecido por el International Council for Laboratory Animals Science y se realizó de acuerdo a los procedimientos normalizados de trabajo del Centro de Toxicología y Biomedicina, Santiago de Cuba. Resultados: Los extractos de Pleurotus ostreatus y el biopreparado de levadura (0,5 mg/kg) no mostraron signos de pirogenicidad. En los resultados del biopreparado (5,0 mg/kg), los valores de temperatura caen en un rango de incertidumbre, según la Farmacopea de Estados Unidos (USP) y se sugirió repetir el estudio. Conclusiones: Los extractos de Pleurotus ostreatus y el biopreparado de Kluyveromyces marxianus (0,5 mg/kg) no indujeron un aumento de temperatura significativo en los animales, lo cual sugiere que en estos bioproductos no existen niveles de endotoxinas que puedan provocar pirogenicidad.
ABSTRACT Introduction: Natural products with pharmacological activity require preclinical evaluations to justify their uses scientifically. The pyrogen assay is a safety pharmacology test performed to determine the presence of endotoxins and it is a valuable method to demonstrate the bio-derivative products safety and their prebiotic potential in the field of immunonutrition. Objective: To evaluate the pyrogenicity of fungal bioproducts from Pleurotus ostreatus (aqueous extracts from mycelium and fruiting bodies) and a biopreparation from Kluyveromyces marxianus yeast, using a pyrogen assay in New Zealand rabbits. Method: Concentrations of 1.0 and 10.0 mg/mL of each sample were tested intravenously at doses of 0.5 and 5.0 mg/kg body weight. The experimental design complied with good laboratory practices as established by the International Council for Laboratory Animal Science and was carried out according to the standard work procedures of the Centro de Toxicología y Biomedicina, Santiago de Cuba. Results: Pleurotus ostreatus extracts and the yeast biopreparation (0.5 mg/kg) showed no signs of pyrogenicity. In the biopreparation results (5.0 mg/kg), temperature values fall in the uncertainty range according to the United States Pharmacopoeia (USP), and therefore it was suggested to repeat the study. Conclusions: Pleurotus ostreatus extracts and Kluyveromyces marxianus biopreparation (0.5 mg/kg) did not induce a significant temperature increase in the animals, thereby suggesting that there are no endotoxin levels in such bioproducts that could cause pyrogenicity.
RESUMO Introdução: Produtos naturais com atividade farmacológica requerem avaliações pré-clínicas que justifiquem seu uso em bases científicas. O ensaio de pirogênio é um teste dentro da Farmacologia de Segurança que é realizado para determinar a presença de endotoxinas e é um método valioso para demonstrar a segurança de bioderivados com potencial prebiótico no campo da imunonutrição. Objetivo: Avaliar a pirogenicidade de bioprodutos fúngicos de Pleurotus ostreatus (extratos aquosos do micélio e corpos de frutificação) e de uma biopreparação da levedura Kluyveromyces marxianus, utilizando o ensaio pirogênico de coelho da Nova Zelândia. Método: Concentrações de 1,0 e 10,0 mg/mL de cada amostra foram testadas por via intravenosa nas doses de 0,5 e 5,0 mg/kg de peso. O desenho experimental obedeceu às boas práticas laboratoriais estabelecidas pelo Conselho Internacional para a Ciência dos Animais de Laboratório e foi realizado de acordo com os procedimentos de trabalho padrão do Centro de Toxicologia e Biomedicina, Santiago de Cuba. Resultados: Os extratos de Pleurotus ostreatus e a biopreparação de leveduras (0,5 mg/kg) não apresentaram sinais de pirogenicidade. Nos resultados da biopreparação (5,0 mg/kg), os valores de temperatura estão dentro de uma faixa de incerteza, segundo a Farmacopeia dos Estados Unidos (USP) e foi sugerido repetir o estudo. Conclusões: Os extratos de Pleurotus ostreatus e a biopreparação de Kluyveromyces marxianus (0,5 mg/kg) não induziram um aumento significativo da temperatura nos animais, o que sugere que não há níveis de endotoxinas nesses bioprodutos que possam causar pirogenicidade.
RESUMO
Kluyveromyces marxianus is an ascomycetous yeast which has shown promising results in cellulosic ethanol and renewable chemicals production. It can survive on a variety of carbon sources under industrially favorable conditions due to its fast growth rate, thermotolerance, and acid tolerance. K. marxianus, is generally regarded as a safe (GRAS) microorganism, is widely recognized as a powerhouse for the production of heterologous proteins and is accepted by the US Food and Drug Administration (USFDA) for its pharmaceutical and food applications. Since lignocellulosic hydrolysates are comprised of diverse monomeric sugars, oligosaccharides and potential metabolism inhibiting compounds, this microorganism can play a pivotal role as it can grow on lignocellulosic hydrolysates coping with vegetal cell wall derived inhibitors. Furthermore, advancements in synthetic biology, for example CRISPR-Cas9 (clustered regularly interspaced short palindromic repeats with Cas9)-mediated genome editing, will enable development of an engineered yeast for the production of biochemicals and biopharmaceuticals having a myriad of industrial applications. Genetic engineering companies such as Cargill, Ginkgo Bioworks, DuPont, Global Yeast, Genomatica, and several others are actively working to develop designer yeasts. Given the important traits and properties of K. marxianus, these companies may find it to be a suitable biocatalyst for renewable chemicals and fuel production on the large scale. This paper reviews the recent progress made with K. marxianus biotechnology for sustainable production of ethanol, and other products utilizing lignocellulosic sugars.
Assuntos
Etanol , Kluyveromyces , Fermentação , Kluyveromyces/genética , Kluyveromyces/metabolismo , Lignina/metabolismoRESUMO
Abstract Fruit juice industry generates massive amount of lignocellulosic by-products annually which are excellent raw materials for bioethanol production. In the current study, bioethanol production from apricot (Prunus armeniaca) pomace by Kluyveromyces marxianus was investigated for the first time. Some key parameters for fermentation such as pretreatment methods, biomass and cellulase loading and time, were optimized. Kluyveromyces marxianus produced 30.09 g/L ethanol in the 20% washed apricot pomace and 120 FPU/g cellulose enzyme loading. The highest theoretical yield and Y P/S values were also observed as 94.7% and 0.50 g/g, respectively, when 15 FPU/g cellulose enzyme was used. These results depict that apricot pomace is a promising feedstock for bioethanol production.
Assuntos
Kluyveromyces , Biocombustíveis , Energia Renovável , Prunus armeniacaRESUMO
Exo-inulinases are versatile enzymes that have gained attention in recent years due to their ability to hydrolyze linear and branched polyfructose chains found in inulines. Agavin, a branched inulin, is found in Agave plant, the raw matter to produce tequila. Our group has isolated several microbial strains from agave bagasse, an agro-industrial residue from tequila production that increases yearly. Strain ISO3, identified as Kluyveromyces marxianus, showed a remarkable activity towards agavin, and from its fermentation liquor an inulinolytic enzyme (Inu-ISO3) was purified. The isolated enzyme is a glycosylated dimeric protein with a molecular mass of ~256 kDa, as determined by DLS and SEC. The enzyme has an isoelectric pH of 4.6 and has both inulinase and invertase activities with an I/S ratio (ratio of activity with agavin to activity with sucrose) of 1.39. The enzyme has temperature and pH optima of 50 °C and 5.5, respectively, and follows hyperbolic kinetics with agavin (kcat of 339 ± 27 s-1 and KM of 11.8 ± 1.5 mM). The remarkable activity of Inu-ISO3 on linear and branched inulin spotlights this enzyme as a potential player in the treatment of agricultural residua for the generation of added-value products.
Assuntos
Agave/microbiologia , Proteínas Fúngicas , Glicosídeo Hidrolases , Inulina/química , Kluyveromyces , Proteínas Fúngicas/química , Proteínas Fúngicas/isolamento & purificação , Glicosídeo Hidrolases/química , Glicosídeo Hidrolases/isolamento & purificação , Hidrólise , Kluyveromyces/enzimologia , Kluyveromyces/isolamento & purificaçãoRESUMO
Apple pomace was studied as a raw material for the production of xylitol and 2G ethanol, since this agroindustrial residue has a high concentration of carbohydrate macromolecules, but is still poorly studied for the production of fermentation bioproducts, such as polyols. The dry biomass was subjected to dilute-acid hydrolysis with H2SO4 to obtain the hemicellulosic hydrolysate, which was concentrated, detoxified and fermented. The hydrolyzate after characterization was submitted to submerged fermentations, which were carried out in Erlenmeyer flasks using, separately, the yeasts Candida guilliermondii and Kluyveromyces marxianus. High cellulose (32.62%) and hemicellulose (23.60%) contents were found in this biomass, and the chemical hydrolysis yielded appreciable quantities of fermentable sugars, especially xylose. Both yeasts were able to metabolize xylose, but Candida guilliermondii produced only xylitol (9.35 g L-1 in 96 h), while K. marxianus produced ethanol as the main product (10.47 g L-1 in 24 h) and xylitol as byproduct (9.10 g L-1 xylitol in 96 h). Maximum activities of xylose reductase and xylitol dehydrogenase were verified after 24 h of fermentation with C. guilliermondii (0.23 and 0.53 U/mgprot, respectively) and with K. marxianus (0.08 e 0.08 U/mgprot, respectively). Apple pomace has shown potential as a raw material for the fermentation process, and the development of a biotechnological platform for the integrated use of both the hemicellulosic and cellulosic fraction could add value to this residue and the apple production chain.
Assuntos
Biotecnologia/métodos , Etanol/química , Malus/metabolismo , Xilitol/química , Aldeído Redutase/química , Biomassa , Reatores Biológicos , Candida , Celulose/metabolismo , D-Xilulose Redutase/química , Fermentação , Glucose/metabolismo , Hidrólise , Kluyveromyces , Polímeros/química , Polissacarídeos/química , Saccharomycetales , Fatores de Tempo , Xilose/metabolismoRESUMO
Lipases are hydrolytic enzymes that break the ester bonds of triglycerides, generating free fatty acids and glycerol. Extracellular lipase activity has been reported for the nonconventional yeast Kluyveromyces marxianus, grown in olive oil as a substrate, and the presence of at least eight putative lipases has been detected in its genome. However, to date, there is no experimental evidence on the physiological role of the putative lipases nor their structural and catalytic properties. In this study, a bioinformatic analysis of the genes of the putative lipases from K. marxianus L-2029 was performed, particularly identifying and characterizing the extracellular expected enzymes, due to their biotechnological relevance. The amino acid sequence of 10 putative lipases, obtained by in silico translation, ranged between 389 and 773 amino acids. Two of the analysed putative proteins showed a signal peptide, 25 and 33 amino acids long for KmYJR107Wp and KmLIP3p, and a molecular weight of 44.53 and 58.23 kDa, respectively. The amino acid alignment of KmLIP3p and KmYJR107Wp with the crystallized lipases from a patatin and the YlLip2 lipase from Yarrowia lipolytica, respectively, revealed the presence of the hydrolase characteristic motifs. From the 3D models of putative extracellular K. marxianus L-2029 lipases, the conserved pentapeptide of each was determined, being GTSMG for KmLIP3p and GHSLG for KmYJR107Wp; besides, the genes of these two enzymes (LIP3 and YJR107W) are apparently regulated by oleate response elements. The phylogenetic analysis of all K. marxianus lipases revealed evolutionary affinities with lipases from abH15.03, abH23.01, and abH23.02 families.
Assuntos
Proteínas de Bactérias/química , Biologia Computacional , Kluyveromyces/enzimologia , Lipase/química , Sequência de Aminoácidos , Proteínas de Bactérias/genética , Biocatálise , Hidrólise , Kluyveromyces/genética , Lipase/genéticaRESUMO
In the present work the effect of three factors: pH, temperature and type of microorganism using a factorial design 32x2 was evaluated on: growth, total cellulases hydrolytic activity (FPases), endoglucanases hydrolytic activity (CMCases), free reducing sugars (FRS), glucose, sucrose, and alcohol production using a culture medium based on mineral salts added with cladodes flour of Opuntia ficus-indica at 20% as the unique carbon source. Two wild microorganisms were used, Acinetobacter pittii a bacteria isolated from decaying cladodes, and Kluyveromyces marxianus a yeast isolated from termite stomach. The maximum hydrolytic activities were obtained with Acinetobacter pittii at 37⯰C and pH 6.5 for total cellulases (0.67⯱â¯0.02 IU/ml) and for endoglucanases (0.23⯱â¯0.02 IU/ml) at 24 and 4â¯h. The maximum production of alcohol was 12.98⯱â¯0.06â¯g/L obtained with Kluyveromyces marxianus at 4â¯h with conditions of 40⯰C and pH 5.5.
RESUMO
Cell physiology parameters are essential aspects of biological processes; however, they are difficult to determine on-line. Dielectric spectroscopy allows the on-line estimation of viable cells and can provide important information about cell physiology during culture. In this study, we investigated the dielectric property variations in Kluyveromyces marxianus SLP1 and Saccharomyces cerevisiae ERD yeasts stressed by 5-hydroxymethyl-2-furaldehyde and 2-furaldehyde during aerobic growth. The dielectric properties of cell permittivity, specific membrane capacitance (Cm), and intracellular conductivity (σIn) were considerably affected by furan aldehydes in the same way that the cell population, viability, cell size, substrate consumption, organic acid production, and respiratory parameters were. The yeasts stressed with furan aldehydes exhibited three physiological states (φ): adaptation, replicating, and nonreplicating states. During the adaptation state, there were small and stable signs of permittivity, Cm, and σIn; additionally, no cell growth was observed. During the replicating state, cell growth was restored, and the cell viability increased; in addition, the permittivity and σIn increased rapidly and reached their maximum values, while the Cm decreased. In the nonreplicating state, the permittivity and σIn were stable, and Cm decreased to its minimum value. Our results demonstrated that knowing dielectric properties allowed us to obtain information about the physiological state of the cells under control and stressed conditions. Since the permittivity, Cm, and σIn are directly associated with the physiological state of the yeast, these results should contribute to a better understanding of the stress response of yeasts and open the possibility to on-line monitor and control the physiological state of the cell in the near future.
Assuntos
Aldeídos/farmacologia , Furanos/farmacologia , Kluyveromyces/efeitos dos fármacos , Kluyveromyces/fisiologia , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/fisiologia , Aldeídos/química , Reatores Biológicos , Espectroscopia Dielétrica , Fermentação , Furanos/química , Viabilidade Microbiana/efeitos dos fármacosRESUMO
The objective of the studies reported in this research communication was to investigate the use of whey contaminated with antibiotics such as cephalosporins, quinolones and tetracyclines as a nutrient medium for the growth of Kluyveromyces marxianus with particular attention to the effect of thermal treatment used to overcome the inhibitory effects of antibiotic concentrations close to the Maximum Residue Limits. The heat treatments at 120 °C for 40 min, 120 °C for 83 min, and 120 °C for 91 min caused total inactivation of cephalosporins, tetracyclines and quinolone residues in whey respectively.
Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Microbiologia de Alimentos/métodos , Temperatura Alta , Kluyveromyces/crescimento & desenvolvimento , Soro do Leite/química , Cefalosporinas/análise , Cefalosporinas/química , Meios de Cultura/química , Estabilidade de Medicamentos , Fermentação , Contaminação de Alimentos/prevenção & controle , Kluyveromyces/efeitos dos fármacos , Kluyveromyces/metabolismo , Lactose/metabolismo , Quinolonas/análise , Quinolonas/química , Tetraciclinas/análise , Tetraciclinas/químicaRESUMO
Recently, biotechnological opportunities have been found in non-Saccharomyces yeasts because they possess metabolic characteristics that lead to the production of compounds of interest. It has been observed that Kluyveromyces marxianus has a great potential in the production of esters, which are aromatic compounds of industrial importance. The genetic bases that govern the synthesis of esters include a large group of enzymes, among which the most important are alcohol acetyl transferases (AATases) and esterases (AEATases), and it is known that some are present in K. marxianus, because it has genetic characteristics like S. cerevisiae. It also has a physiology suitable for biotechnological use since it is the eukaryotic microorganism with the fastest growth rate and has a wide range of thermotolerance with respect to other yeasts. In this work, the enzymatic background of K. marxianus involved in the synthesis of esters is analyzed, based on the sequences reported in the NCBI database.
Assuntos
Ésteres/metabolismo , Microbiologia Industrial , Kluyveromyces/enzimologia , Aciltransferases , Álcool Desidrogenase , Esterases , Fermentação , Oxigenases de Função Mista , OdorantesRESUMO
Mango fruits (Mangifera indica L.) are highly perishable, causing postharvest losses and producing agroindustrial waste. In the present work, native yeasts were used to evaluate ethanol production in overripe mango pulp. The two isolated strains showed similar sequences in the 18S rDNA region corresponding to Kluyveromyces marxianus, being different to the data reported in the NCBI database. Values of up to 5% ethanol (w/v) were obtained at the end of fermentation, showing a productivity of 4g/l/day, a yield of up to 49% of ethanol and a process efficiency of 80%. These results represent a viable option for using the surplus production and all the fruits that have suffered mechanical injury that are not marketable and are considered as agroindustrial waste, thus achieving greater income and less postharvest losses.
Las frutas de mango (Mangifera indica L.) son altamente perecederas, lo cual causa pérdidas poscosecha y produce desechos agroindustriales. En el presente trabajo, se utilizaron 2 levaduras nativas para evaluar la producción de etanol en pulpa de mango senescente. Las 2 cepas aisladas mostraron similitud en la región 18S ADNr, correspondiente a Kluyveromyces marxianus, la cual es diferente a lo reportado en la base de datos del NCBI. Se obtuvieron valores de hasta el 6% de etanol (v/v) al final de la fermentación, con una productividad de hasta 4g/l/día, un rendimiento de hasta 49% de etanol y una eficiencia en el proceso fermentativo del 80%. Esto representa una opción viable para utilizar excedentes de producción o frutos que han sufrido daño mecánico y no son comercializables, al lograr más ingresos y menos pérdida poscosecha.