RESUMEN
A novel actinomycete, designated NUM-2625T, was isolated as an endophytic bacterium in aerial parts of Comarum salesowianum, an endemic species in the Altai, Himalaya mountain chain area, collected from Khasagt Khairkhan Mountain in Mongolia. The 16S rRNA gene sequence of strain NUM-2625T showed the highest similarity to Actinocatenispora thailandica TT2-10T (99.4â%), Actinocatenispora sera KV-744T (99.3â%), and Actinocatenispora rupis CS5-AC17T (97.7â%). Chemotaxonomic properties of strain NUM-2625T were essentially consistent with those of the genus Actinocatenispora, such as the presence of meso-diaminopimelic acid as the diagnostic diamino acid of the peptidoglycan, MK-9(H4) and MK-9(H6) as the major menaquinones, and iso-C16â:â0, iso-C15â:â0, iso-C14â:â0 3-OH, and anteiso-C17â:â0 as the major fatty acids. Meanwhile, digital DNA-DNA hybridization and average nucleotide identity values revealed a low relatedness between strain NUM-2625T and the other type strains of the genus Actinocatenispora. In addition, strain NUM-2625T exhibited several phenotypic properties that could be used to distinguish it from its closest relatives. Based on the results of polyphasic analyses, strain NUM-2625T represents a novel species in the genus Actinocatenispora, for which the name Actinocatenispora comari sp. nov. is proposed. The type strain is NUM-2625T (=NBRC 114660T=TBRC 13496T).
Asunto(s)
Micromonosporaceae/clasificación , Filogenia , Componentes Aéreos de las Plantas/microbiología , Rosácea/microbiología , Técnicas de Tipificación Bacteriana , Composición de Base , ADN Bacteriano/genética , Ácido Diaminopimélico/química , Endófitos/clasificación , Endófitos/aislamiento & purificación , Ácidos Grasos/química , Micromonosporaceae/aislamiento & purificación , Mongolia , Hibridación de Ácido Nucleico , Fosfolípidos/química , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Vitamina K 2/análogos & derivados , Vitamina K 2/químicaRESUMEN
Chickpea (Cicer arietinum L., Fabaceae) is the second most important legume after common bean (Phaseolus vulgaris L., Fabaceae) and third in production among the legumes grains worldwide. Ascochyta blight and Fusarium wilt are among the main fungal infections which cause the major losses of chickpea crop. In this work we report the phyto-pathogen controlling properties of 24 endophyte Phomopsis/Diaporthe isolates on the chickpea fungal pathogens Ascochyta rabiei, Fusarium oxysporum and Fusarium solani. The Phomopsis/Diaporthe strains were isolated amongst a total of 62 endophytic fungi from the aerial parts of the herbaceous perennial American plant Peperomia obtusifolia (Piperaceae) along with Fusarium, Septoria, Colletotrichum, Alternaria and Roussoella genera among others. Phomopsis/Diaporthe isolates were identified as Diaporthe infecunda (12 isolates), Diaporthe sackstoni (1 isolate), Diaporthe cf. brasiliensis (4 isolates) and Phomopsis cf. tuberivora (7 isolates). All the Phomopsis/Diaporthe strains antagonized A. rabiei strain AR2 with a mean of inhibition (% I) of 86.59 ± 1.49% in dual cultures. The metabolic characterization of the Phomopsis/Diaporthe strains showed groups in three clusters which were in agreement with the taxonomic identification. Bioautographic evaluation of organic extracts showed that those of D. cf. brasiliensis and D. infecunda were better as inhibitors. Strain Po 45 was one of the most active (cluster 1, 96.87% I), and its ethyl acetate extract inhibited A. rabiei growth in a bioautographic assay until at least 10 µg/mm applied showing a specific chromatographic band as the responsible of the A. rabiei inhibition.
Asunto(s)
Ascomicetos/crecimiento & desarrollo , Cicer/crecimiento & desarrollo , Endófitos/fisiología , Peperomia/microbiología , Enfermedades de las Plantas/prevención & control , Ascomicetos/clasificación , Ascomicetos/aislamiento & purificación , Ascomicetos/patogenicidad , Ascomicetos/fisiología , Cicer/microbiología , Técnicas de Cocultivo , Productos Agrícolas/crecimiento & desarrollo , Productos Agrícolas/microbiología , Endófitos/clasificación , Endófitos/aislamiento & purificación , Viabilidad Microbiana , Filogenia , Componentes Aéreos de las Plantas/microbiología , Enfermedades de las Plantas/microbiologíaRESUMEN
Although studies of biogeography in soil bacterial communities have attracted considerable attention, the generality of these patterns along with assembly processes and underlying drivers is poorly understood in the inner tissues of plants. Plant tissues provide unique ecological habitats for microorganisms, which play an essential role in plant performance. Here, we compared core bacterial communities among five soil-plant associated compartments of common bean across five sampling sites in China. Neutral and null modelling consistently suggested that stochastic processes dominated the core community assembly processes and escalated from the belowground compartments to the inner tissues of aerial plant parts. The multiple distance-decay relationships also varied and had flattened patterns in the stem endosphere, which were shaped by distinct environmental factors in each compartment. Coexistence patterns also varied in topological features, in addition with the sparsest networks in the stem endosphere resulted from the interaction with the stochastic processes. This study considerably expanded our understanding of various biogeographic patterns, assembly processes, and the underlying mechanisms of core bacterial communities between aerial and belowground compartments of common bean. That will provide a scientific basis for the reasonable regulation of core bacterial consortia to get better plant performance.
Asunto(s)
Bacterias/aislamiento & purificación , Microbiota , Phaseolus/microbiología , Microbiología del Suelo , Bacterias/clasificación , Bacterias/genética , China , Ecosistema , Phaseolus/crecimiento & desarrollo , Componentes Aéreos de las Plantas/microbiología , Suelo/química , Procesos EstocásticosRESUMEN
The aboveground parts of terrestrial plants, collectively called the phyllosphere, have a key role in the global balance of atmospheric carbon dioxide and oxygen. The phyllosphere represents one of the most abundant habitats for microbiota colonization. Whether and how plants control phyllosphere microbiota to ensure plant health is not well understood. Here we show that the Arabidopsis quadruple mutant (min7 fls2 efr cerk1; hereafter, mfec)1, simultaneously defective in pattern-triggered immunity and the MIN7 vesicle-trafficking pathway, or a constitutively activated cell death1 (cad1) mutant, carrying a S205F mutation in a membrane-attack-complex/perforin (MACPF)-domain protein, harbour altered endophytic phyllosphere microbiota and display leaf-tissue damage associated with dysbiosis. The Shannon diversity index and the relative abundance of Firmicutes were markedly reduced, whereas Proteobacteria were enriched in the mfec and cad1S205F mutants, bearing cross-kingdom resemblance to some aspects of the dysbiosis that occurs in human inflammatory bowel disease. Bacterial community transplantation experiments demonstrated a causal role of a properly assembled leaf bacterial community in phyllosphere health. Pattern-triggered immune signalling, MIN7 and CAD1 are found in major land plant lineages and are probably key components of a genetic network through which terrestrial plants control the level and nurture the diversity of endophytic phyllosphere microbiota for survival and health in a microorganism-rich environment.
Asunto(s)
Arabidopsis/genética , Arabidopsis/microbiología , Redes Reguladoras de Genes/genética , Componentes Aéreos de las Plantas/genética , Componentes Aéreos de las Plantas/microbiología , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/prevención & control , Arabidopsis/inmunología , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Muerte Celular , Ambiente , Firmicutes/genética , Firmicutes/aislamiento & purificación , Genes de Plantas/genética , Genotipo , Factores de Intercambio de Guanina Nucleótido/genética , Factores de Intercambio de Guanina Nucleótido/metabolismo , Homeostasis , Microbiota/genética , Microbiota/fisiología , Mutación , Fenotipo , Enfermedades de las Plantas/inmunología , Enfermedades de las Plantas/microbiología , Inmunidad de la Planta/genética , Hojas de la Planta/genética , Hojas de la Planta/microbiología , Proteobacteria/genética , Proteobacteria/aislamiento & purificaciónRESUMEN
Two novel eremophylane acetophenone conjugates, colletotricholides A (1) and B (2), were isolated from the solid fermentation cultures of an endophytic fungus Colletotrichum gloeosporioides XL1200 isolated from the aerial parts of Salvia miltiorrhiza. The chemical structures of 1-2 were characterized by extensive spectroscopic methods and single-crystal X-ray crystallography. Structurally, compounds 1-2 are two unusual eremophylane acetophenone conjugates originating from the hybrid pathways of polyketide synthase and sesquiterpene synthase. In addition, compounds 1-2 were inactive against tested pathogens.
Asunto(s)
Acetofenonas/química , Colletotrichum/química , Salvia miltiorrhiza/microbiología , Antibacterianos/química , Antibacterianos/farmacología , Antifúngicos/química , Antifúngicos/farmacología , Bacterias/efectos de los fármacos , Endófitos , Hongos/efectos de los fármacos , Modelos Moleculares , Estructura Molecular , Componentes Aéreos de las Plantas/microbiologíaRESUMEN
AIMS: This research aimed to identify factors influencing endophyte community structure in apple shoots and the bioactivity of cultured representatives against the fungal pathogen Neonectria ditissima. METHODS AND RESULTS: The endophyte community in leaves and stems of the apple cultivars 'Royal Gala' and 'Braeburn' were analysed by a cultivation-independent method (PCR-DGGE) which showed that tissue type, cultivar and site were determinant factors, with the endophyte taxa in 'Royal Gala' more variable than that in 'Braeburn', with leaf endophyte communities typically differing from stems in both cultivars. Seasonal (spring vs autumn) and regional (Nelson vs Hawke's Bay) variations were not obvious in woody stems. A collection of 783 bacterial and 87 fungal endophytes were recovered from leaves and stems of 'Royal Gala', 'Braeburn', 'Scilate' and/or 'Scifresh' from Nelson (nine sites) and Hawke's Bay (five sites) in spring and from Nelson (three sites) in autumn. A dual culture plating assay was used to test their ability to inhibit the mycelial growth of N. ditissima. Thirteen bacterial (mean of percent inhibition ≥20%) and 17 fungal isolates were antagonistic towards N. ditissima. These isolates belonged to the bacterial genera Bacillus and Pseudomonas, and fungal genera Chaetomium, Epicoccum, Biscogniauxia, Penicillium, Diaporthe, Phlyctema and two unidentified fungal isolates. CONCLUSIONS: Endophyte communities in apple shoots were determined by tissue type, cultivar and site. Endophytic bacterial and fungal isolates inhibiting N. ditissima growth in vitro were found. SIGNIFICANCE AND IMPACT OF THE STUDY: These results provided new evidence of factors influencing apple endophyte community in New Zealand. Endophytes with potential to reduce N. ditissima infection were identified, with the potential to be developed into a biocontrol strategy for European canker.
Asunto(s)
Endófitos/fisiología , Hypocreales/fisiología , Malus/microbiología , Control Biológico de Vectores/métodos , Enfermedades de las Plantas/prevención & control , Antibiosis , Bacterias/clasificación , Bacterias/genética , Bacterias/aislamiento & purificación , Endófitos/clasificación , Endófitos/aislamiento & purificación , Hongos/clasificación , Hongos/genética , Hongos/aislamiento & purificación , Nueva Zelanda , Componentes Aéreos de las Plantas/microbiología , Enfermedades de las Plantas/microbiologíaRESUMEN
The Vietnamese Mekong delta is one of the largest rice-producing areas globally. Methylobacterium spp. are persistent colonizers of the rice plant and exert beneficial effects on plant growth and health. Sixty-one Methylobacterium strains belonging to seven species were predominantly isolated from the phyllosphere of rice cultivated in six Mekong delta provinces. Inoculation tests revealed that some strains exhibited plant growth-promoting activity. Moreover, three strains possessed the novel characteristics of inducing leaf bleaching and killing rice seedlings. These results revealed the complex diversity of Methylobacterium in Mekong delta rice and that healthy and productive rice cultivation requires a proper balance of Methylobacterium.
Asunto(s)
Variación Genética , Methylobacterium/genética , Oryza/microbiología , Lactuca/crecimiento & desarrollo , Lactuca/microbiología , Methylobacterium/clasificación , Methylobacterium/fisiología , Oryza/crecimiento & desarrollo , Componentes Aéreos de las Plantas/microbiología , Reguladores del Crecimiento de las Plantas/fisiología , VietnamRESUMEN
Despite numerous studies on plant endophytes, little is known about fungal communities associated with different aboveground tissues of living trees. We used high-throughput sequencing to compare the diversity and community structure of fungi inhabiting leaves, branches and trunks of Alnus incana and Corylus avellana growing at three hemiboreal forest sites. Our analysis revealed that tree organs are the main determinants of the structure of fungal communities, whereas the effects of host species and locality remained secondary and negligible, respectively. The structure of fungal communities in trunks was the most distinct compared to that in leaves and branches. The foliar fungal communities were more similar within than between individual trees, implying that certain fungi may grow through parts of the tree crown. The weak effect of locality compared to host organs and species identity suggests that the structural variation of fungal communities in the aboveground parts of trees depends mainly on deterministic factors rather than dispersal limitation.
Asunto(s)
Bosques , Micobioma/genética , Árboles/microbiología , Biodiversidad , Endófitos/clasificación , Endófitos/genética , Endófitos/aislamiento & purificación , Hongos/clasificación , Hongos/genética , Hongos/aislamiento & purificación , Especificidad del Huésped , Componentes Aéreos de las Plantas/microbiología , Árboles/anatomía & histología , Árboles/clasificaciónRESUMEN
Non-pathogenic yeasts antagonising microorganisms that cause pre- and postharvest diseases of plants have been found in diverse habitats. Their practical applicability as biocontrol agents (BCAs) depends on the strength of their antagonistic activity and/or spectrum of sensitive target microorganisms. In this study, yeasts were isolated from the phylloplane and fruits of plants growing in the alkaline water lake region Wadi El-Natrun, Egypt, and tested for antifungal and antibacterial activity. All phylloplane yeast isolates belonged to the Basidiomycota and most of them could antagonise at least certain test organisms. One group of isolates showing strong antagonism against almost all fungi and yeasts appears to represent a hitherto undescribed species distantly related to the smut genus Sporisorium. This is the first report of antagonistic activity in Sporisorium. The isolates assigned to Naganishia and Papiliotrema were more effective against bacteria. The broadest range and intensity of antagonism was observed in the fruit-associated strains belonging to the ascomycetous species Wickerhamomyces subpelliculosus. The Wickerhamomyces strains are good broad-spectrum BCA candidates, the Sporisorium strains could be used as efficient antifungal BCAs, whereas the Papiliotrema isolate can be exploited as an antibacterial biocontrol agent.
Asunto(s)
Antibiosis , Lagos/microbiología , Componentes Aéreos de las Plantas/microbiología , Ustilaginales/fisiología , Levaduras/fisiología , Ecosistema , Egipto , Lagos/análisis , Plantas/microbiología , Cloruro de Sodio/análisis , Cloruro de Sodio/metabolismo , Ustilaginales/clasificación , Ustilaginales/genética , Ustilaginales/aislamiento & purificación , Levaduras/clasificación , Levaduras/genética , Levaduras/aislamiento & purificaciónRESUMEN
Fungal pathogens constitute a severe yield-limiting factor for the pasture crop alfalfa (Medicago sativa L.). Eleven phenolic compounds, including a new isoflavane, were isolated from the Uromyces striatus Schroet. infected alfalfa. The effect of infection with U. striatus Schroet. on the phytochemical profile of alfalfa was investigated using ultra-performance liquid chromatography (UPLC), and the antifungal properties of isolated compounds against a range of pathogens were tested. It was found that the contents of most of the isolated compounds in U. striatus infected alfalfa were higher than those in healthy alfalfa. Compounds 1-5 exhibited a moderate inhibitory activity against Curvularia lunata with 40.14±1.63 %, 48.03±1.22 %, 57.54±1.18 %, 50.10±1.56 %, and 61.54±2.14 % inhibition ratio at the concentration of 50â µg/mL. Compounds 3 and 5 showed a weak inhibitory activity against Fusarium graminearum with the EC50 values of 104.2±2.66 and 123.0±1.23â µg/mL, and a moderate inhibitory activity against Bipolaris sorokinianum with the EC50 values of 39.1±2.05 and 95.0±1.01â µg/mL, respectively. In pot experiments with wheat, compounds 1-5 possessed desirable protective efficacy of over 80 % and curative effectiveness of over 50 % against Puccinia striiformis f. sp. tritici at a concentration of 0.5â mg/mL.
Asunto(s)
Antifúngicos/farmacología , Flavonas/química , Hongos/efectos de los fármacos , Medicago sativa/química , Antifúngicos/química , Antifúngicos/aislamiento & purificación , Ascomicetos/efectos de los fármacos , Basidiomycota/efectos de los fármacos , Cromatografía Líquida de Alta Presión , Flavonas/aislamiento & purificación , Flavonas/farmacología , Fusarium/efectos de los fármacos , Espectroscopía de Resonancia Magnética , Medicago sativa/metabolismo , Medicago sativa/microbiología , Conformación Molecular , Fitoquímicos/química , Fitoquímicos/aislamiento & purificación , Fitoquímicos/farmacología , Componentes Aéreos de las Plantas/química , Componentes Aéreos de las Plantas/metabolismo , Componentes Aéreos de las Plantas/microbiología , Enfermedades de las Plantas/microbiologíaRESUMEN
An indigenous maize landrace from the Sierra Mixe region of Oaxaca, Mexico exhibits extensive formation of aerial roots which exude large volumes of a polysaccharide-rich gel matrix or "mucilage" that harbors diazotrophic microbiota. We hypothesize that the mucilage associated microbial community carries out multiple functions, including disassembly of the mucilage polysaccharide. In situ, hydrolytic assay of the mucilage revealed endogenous arabinofuranosidase, galactosidase, fucosidase, mannosidase and xylanase activities. Screening the mucilage against plant cell wall glycan-specific monoclonal antibodies recognized the presence of carbohydrate epitopes of hemicellulosic polysaccharides like xyloglucan (both non-fucosylated and fucosylated), xylan (both substituted and unsubstituted xylan domains) and pectic-arabinogalactans, all of which are potential carbon sources for mucilage microbial residents. Mucilage metagenome annotation using MG-RAST identified the members forming the microbial community, and gene fragments with predicted functions associated with carbohydrate disassembly. Data from the in situ hydrolytic activity and monoclonal antibody screening assays were used to guide the selection of five full length genes with predicted glycosyl hydrolase function from the GenBank database that were similar to gene fragments of high relative abundance in the mucilage metagenomes. These five genes were then synthesized for recombinant production in Escherichia coli. Here we report the characterization of an α-N-arabinofuranosidase (GH51) and an oligosaccharide reducing-end xylanase (GH8) from Flavobacterium johnsoniae; an α-L-fucosidase (GH29) and a xylan ß-1,4 xylosidase (GH39) from Spirosoma linguale, and a ß-mannosidase (GH2) from Agrobacterium fabrum. Biochemical characterization of these enzymes revealed a ß-Mannosidase that also exhibits a secondary activity towards the cleavage of galactosyl residues. We also describe two xylanases (GH8 and GH39) from underexplored glycosyl hydrolase families, one thermostable α-L-Fucosidase (GH29) and a thermostable α-N-Arabinofuranosidase (GH51).
Asunto(s)
Glicósido Hidrolasas/genética , Glicósido Hidrolasas/metabolismo , Zea mays/enzimología , Zea mays/microbiología , Anticuerpos Monoclonales , Proteínas Bacterianas/química , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Pared Celular/metabolismo , Glicósido Hidrolasas/química , Metagenoma , Microbiota/genética , Filogenia , Componentes Aéreos de las Plantas/enzimología , Componentes Aéreos de las Plantas/microbiología , Mucílago de Planta/química , Mucílago de Planta/metabolismo , Polisacáridos/inmunología , Polisacáridos/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismoRESUMEN
A viability quantitative PCR (v-qPCR) assay was developed for the unambiguous detection and quantification of Lactobacillus plantarum PM411 viable cells in aerial plant surfaces. A 972-bp region of a PM411 predicted prophage with mosaic architecture enabled the identification of a PM411 strain-specific molecular marker. Three primer sets with different amplicon lengths (92, 188, and 317 bp) and one TaqMan probe were designed. All the qPCR assays showed good linearity over a 4-log range and good efficiencies but differed in sensitivity. The nucleic acid-binding dye PEMAX was used to selectively detect and enumerate viable bacteria by v-qPCR. The primer set amplifying a 188-bp DNA fragment was selected as the most suitable for v-qPCR. The performance of the method was assessed on apple blossoms, pear, strawberry, and kiwifruit leaves in potted plants under controlled environmental conditions, as well as pear and apple blossoms under field conditions, by comparing v-qPCR population estimations to those obtained by qPCR and specific plate counting on de Man-Rogosa-Sharpe (MRS)-rifampin. The population estimation did not differ significantly between methods when conditions were conducive to bacterial survival. However, under stressful conditions, differences between methods were observed due to cell death or viable-but-nonculturable state induction. While qPCR overestimated the population level, plate counting underestimated this value in comparison to v-qPCR. PM411 attained stable population levels of viable cells on the flower environment under high relative humidity. However, the unfavorable conditions on the leaf surface and the relatively dryness in the field caused an important decrease in the viable population.IMPORTANCE The v-qPCR method in combination with plate counting and qPCR is a powerful tool for studies of colonization and survival under field conditions, to improve formulations and delivery strategies of PM411, and to optimize the dose and timing of spray schedules. It is expected that PEMAX v-qPCR could also be developed for monitoring other strains on plant surfaces not only as biological control agents but also beneficial bacteria useful in the sustainable management of crop production.
Asunto(s)
Agentes de Control Biológico/química , Lactobacillus plantarum/crecimiento & desarrollo , Viabilidad Microbiana , Componentes Aéreos de las Plantas/microbiología , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Agentes de Control Biológico/aislamiento & purificación , Cartilla de ADN/genética , ADN Bacteriano/genética , Fragaria/crecimiento & desarrollo , Fragaria/microbiología , Lactobacillus plantarum/genética , Lactobacillus plantarum/aislamiento & purificación , Malus/crecimiento & desarrollo , Malus/microbiología , Enfermedades de las Plantas/prevención & control , Pyrus/crecimiento & desarrollo , Pyrus/microbiología , Especificidad de la EspecieRESUMEN
Fungi, like other organisms, actively sense the environmental light conditions in order to drive adaptive responses, including protective mechanisms against the light-associated stresses, and to regulate development. Ecological niches are characterized by different light regimes, for instance light is absent underground, and light spectra from the sunlight are changed underwater or under the canopy of foliage due to the absorption of distinct wavelengths by bacterial, algal and plant pigments. Considering the fact that fungi have evolved to adapt to their habitats, the complexities of their 'visual' systems may vary significantly. Fungi that are pathogenic on plants experience a special light regime because the host always seeks the optimum light conditions for photosynthesis - and the pathogen has to cope with this environment. When the pathogen lives under the canopy and is indirectly exposed to sunlight, it is confronted with an altered light spectrum enriched for green and far-red light. Botrytis cinerea, the gray mold fungus, is an aggressive plant pathogen mainly infecting the above-ground parts of the plant. As outlined in this review, the Leotiomycete maintains a highly sophisticated light signaling machinery, integrating (near)-UV, blue, green, red and far-red light signals by use of at least eleven potential photoreceptors to trigger a variety of responses, i.e. protection (pigmentation, enzymatic systems), morphogenesis (conidiation, apothecial development), entrainment of a circadian clock, and positive and negative tropism of multicellular (conidiophores, apothecia) and unicellular structures (conidial germ tubes). In that sense, 'looking through the eyes' of this plant pathogen will expand our knowledge of fungal photobiology.
Asunto(s)
Botrytis/patogenicidad , Botrytis/efectos de la radiación , Luz , Componentes Aéreos de las Plantas/microbiología , Relojes Circadianos/fisiología , Relojes Circadianos/efectos de la radiación , Criptocromos/fisiología , Fotorreceptores Microbianos/fisiología , Fototropismo/fisiología , Fototropismo/efectos de la radiación , Transducción de Señal/efectos de la radiación , Virulencia/efectos de la radiaciónRESUMEN
High enzyme loading and low productivity are two major issues impeding low cost ethanol production from lignocellulosic biomass. This work applied rapid bioconversion with integrated recycle technology (RaBIT) and extractive ammonia (EA) pretreatment for conversion of corn stover (CS) to ethanol at high solids loading. Enzymes were recycled via recycling unhydrolyzed solids. Enzymatic hydrolysis with recycled enzymes and fermentation with recycled yeast cells were studied. Both enzymatic hydrolysis time and fermentation time were shortened to 24 h. Ethanol productivity was enhanced by two times and enzyme loading was reduced by 30%. Glucan and xylan conversions reached as high as 98% with an enzyme loading of as low as 8.4 mg protein per g glucan. The overall ethanol yield was 227 g ethanol/kg EA-CS (191 g ethanol/kg untreated CS). Biotechnol. Bioeng. 2017;114: 1713-1720. © 2017 Wiley Periodicals, Inc.
Asunto(s)
Amoníaco/química , Celulasa/química , Etanol/aislamiento & purificación , Etanol/metabolismo , Componentes Aéreos de las Plantas/microbiología , Saccharomyces cerevisiae/metabolismo , Zea mays/microbiología , Reactores Biológicos/microbiología , Hidrólisis , Lignina/química , Lignina/metabolismo , Extracción Líquido-Líquido/métodos , Componentes Aéreos de las Plantas/química , Reciclaje/métodos , Integración de Sistemas , Zea mays/químicaRESUMEN
Lignocellulose is a polysaccharide and an abundant biomass resource that widely exists in grains, beans, rice, and their by-products. Over 10 million tons of lignocellulose resources and processing products are produced every year in China. Three recombinant Y. lipolytica strains with cellulase (ß-glucosidase, endoglucanase and cellobiohydrolase) were constructed. The enzymatic activities of these enzymes were 14.181 U/mL, 16.307 U/mL, and 17.391 U/mL, respectively. The whole cell cellulases were used for a stover bio-transformation. The celluloses in the stover were partly degraded by the cellulases, and the degradation products were transformed into single cell protein (SCP) by the Y. lipolytica cells. After 15 d of fermentation with the whole cell cellulases, the protein content of the maize stover and the rice straw reached 16.23% and 14.75%, which increased by 168.26% and 161.52% compared with the control, respectively. This study provides a new stage for the efficient utilization of stover in the feed industry.
Asunto(s)
Celulasas/genética , Lignina/metabolismo , Ingeniería Metabólica/métodos , Oryza/microbiología , Recombinación Genética/genética , Yarrowia/fisiología , Biotransformación/genética , Mejoramiento Genético/métodos , Componentes Aéreos de las Plantas/microbiologíaRESUMEN
The present work is aimed to evaluate the saccharification potential of a thermostable ß-xylosidase cloned from Bacillus licheniformis into Escherichia coli for production of bioethanol from plant biomass. Recombinant ß-xylosidase enzyme possesses the ability of bioconversion of plant biomass like wheat straw, rice straw and sugarcane bagass. By using this approach, plant biomass that mainly constitute cellulose can be converted to reducing sugars that could then be easily converted to bioethanol by simple fermentation process. The production of bioethanol will help to overcome energy requirements due to depleting fossil fuels and will also help to protect environment by reducing greenhouse gas emission. In the end, future directions are briefly mentioned that can be utilized to reduce the cost and increase the yield of biofuels.
Asunto(s)
Bacillus licheniformis/enzimología , Escherichia coli/genética , Escherichia coli/metabolismo , Etanol/metabolismo , Componentes Aéreos de las Plantas/microbiología , Ingeniería de Proteínas/métodos , Xilosidasas/metabolismo , Bacillus licheniformis/genética , Activación Enzimática , Estabilidad de Enzimas , Etanol/aislamiento & purificación , Mejoramiento Genético/métodos , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Temperatura , Xilosidasas/genéticaRESUMEN
Endophytic bacteria are critical for plant growth and health. However, compositional and functional responses of bacterial endophyte communities towards agricultural practices are still poorly understood. Hence, we analyzed the influence of fertilizer application and mowing frequency on bacterial endophytes in three agriculturally important grass species. For this purpose, we examined bacterial endophytic communities in aerial plant parts of Dactylis glomerata L., Festuca rubra L., and Lolium perenne L. by pyrotag sequencing of bacterial 16S rRNA genes over two consecutive years. Although management regimes influenced endophyte communities, observed responses were grass species-specific. This might be attributed to several bacteria specifically associated with a single grass species. We further predicted functional profiles from obtained 16S rRNA data. These profiles revealed that predicted abundances of genes involved in plant growth promotion or nitrogen metabolism differed between grass species and between management regimes. Moreover, structural and functional community patterns showed no correlation to each other indicating that plant species-specific selection of endophytes is driven by functional rather than phylogenetic traits. The unique combination of 16S rRNA data and functional profiles provided a holistic picture of compositional and functional responses of bacterial endophytes in agricultural relevant grass species towards management practices.
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Bacterias/aislamiento & purificación , Poaceae/microbiología , Agricultura , Bacterias/genética , Nitrógeno/metabolismo , Componentes Aéreos de las Plantas/microbiología , Desarrollo de la Planta , Poaceae/crecimiento & desarrollo , ARN Ribosómico 16S/genética , ARN Ribosómico 16S/metabolismo , Especificidad de la Especie , SimbiosisRESUMEN
Spices and herbs have been used since ancient times as flavor and aroma enhancers, colorants, preservatives, and traditional medicines. There are more than 30 spices and herbs of global economic and culinary importance. Among the spices, black pepper, capsicums, cumin, cinnamon, nutmeg, ginger, turmeric, saffron, coriander, cloves, dill, mint, thyme, sesame seed, mustard seed, and curry powder are the most popular spices worldwide. In addition to their culinary uses, a number of functional properties of aromatic herbs and spices are also well described in the scientific literature. However, spices and herbs cultivated mainly in tropic and subtropic areas can be exposed to contamination with toxigenic fungi and subsequently mycotoxins. This review provides an overview on the mycotoxin risk in widely consumed spices and aromatic herbs.
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Contaminación de Alimentos , Salud Global , Micotoxinas/toxicidad , Especias/análisis , Alimentación Animal/análisis , Alimentación Animal/microbiología , Alimentación Animal/toxicidad , Bienestar del Animal , Animales , Contaminación de Alimentos/prevención & control , Humanos , Legislación Alimentaria , Micotoxinas/análisis , Componentes Aéreos de las Plantas/química , Componentes Aéreos de las Plantas/crecimiento & desarrollo , Componentes Aéreos de las Plantas/microbiología , Componentes Aéreos de las Plantas/toxicidad , Plantas Comestibles/química , Plantas Comestibles/crecimiento & desarrollo , Plantas Comestibles/microbiología , Plantas Comestibles/toxicidad , Plantas Medicinales/química , Plantas Medicinales/crecimiento & desarrollo , Plantas Medicinales/microbiología , Plantas Medicinales/toxicidad , Rizoma/química , Rizoma/crecimiento & desarrollo , Rizoma/microbiología , Rizoma/toxicidad , Semillas/química , Semillas/crecimiento & desarrollo , Semillas/microbiología , Semillas/toxicidad , Especias/efectos adversos , Especias/normasRESUMEN
Production of fumaric acid from alkali-pretreated corncob (APC) at high solids loading was investigated using a combination of separated hydrolysis and fermentation (SHF) and fed-batch simultaneous saccharification and fermentation (SSF) by Rhizopus oryzae. Four different fermentation modes were tested to maximize fumaric acid concentration at high solids loading. The highest concentration of 41.32 g/L fumaric acid was obtained from 20 % (w/v) APC at 38 °C in the combined SHF and fed-batch SSF process, compared with 19.13 g/L fumaric acid in batch SSF alone. The results indicated that a combination of SHF and fed-batch SSF significantly improved production of fumaric acid from lignocellulose by R. oryzae than that achieved with batch SSF at high solids loading.
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Técnicas de Cultivo Celular por Lotes/métodos , Fumaratos/metabolismo , Lignina/metabolismo , Rhizopus/metabolismo , Zea mays/química , Zea mays/microbiología , Álcalis/química , Reactores Biológicos/microbiología , Metabolismo de los Hidratos de Carbono/fisiología , Fumaratos/aislamiento & purificación , Glucosa/metabolismo , Hidrólisis , Residuos Industriales/prevención & control , Componentes Aéreos de las Plantas/química , Componentes Aéreos de las Plantas/microbiología , Hidróxido de Sodio/químicaRESUMEN
Biological pretreatment of lignocellulosic biomass by white-rot fungus can represent a low-cost and eco-friendly alternative to harsh physical, chemical, or physico-chemical pretreatment methods to facilitate enzymatic hydrolysis. In this work, solid-state cultivation of corn stover with Phlebia brevispora NRRL-13018 was optimized with respect to duration, moisture content and inoculum size. Changes in composition of pretreated corn stover and its susceptibility to enzymatic hydrolysis were analyzed. About 84% moisture and 42 days incubation at 28°C were found to be optimal for pretreatment with respect to enzymatic saccharification. Inoculum size had little effect compared to moisture level. Ergosterol data shows continued growth of the fungus studied up to 57 days. No furfural and hydroxymethyl furfural were produced. The total sugar yield was 442 ± 5 mg/g of pretreated corn stover. About 36 ± 0.6 g ethanol was produced from 150 g pretreated stover per L by fed-batch simultaneous saccharification and fermentation (SSF) using mixed sugar utilizing ethanologenic recombinant Eschericia coli FBR5 strain. The ethanol yields were 32.0 ± 0.2 and 38.0 ± 0.2 g from 200 g pretreated corn stover per L by fed-batch SSF using Saccharomyces cerevisiae D5A and xylose utilizing recombinant S. cerevisiae YRH400 strain, respectively. This research demonstrates that P. brevispora NRRL-13018 has potential to be used for biological pretreatment of lignocellulosic biomass. This is the first report on the production of ethanol from P. brevispora pretreated corn stover. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:365-374, 2017.