Production and action of an Aspergillus phoenicis enzymatic pool using different carbon sources

Aspergillus phoenicis is an interesting heat tolerant fungus that can synthesize enzymes with several applications in the food industry due to its great hydrolytic potential. In this work, the fungus produced high enzymatic levels when cultivated on inexpensive culture media consisting of flakes from different origins such as cassava flour, wheat fibre, crushed soybean, agro-industrial wastes, starch, glucose or maltose. Several enzymatic systems were produced from these carbon sources, but amylase was the most evident, followed by pectinase and xylanase. Traces of CMCases, avicelase, lipase, β-xylosidase, β-glucosidase and α-glucosidase activities were also detected. Amylases were produced on rye flakes, starch, oat flakes, corn flakes, cassava flour and wheat fibre. Significant amylolytic levels were produced in the culture medium with glucose or when this sugar was exhausted, suggesting an enzyme in the constitutive form. Cassava flour, rye, oats, barley and corn flakes were also used as substrates in the hydrolytic reactions, aiming to verify the liberation potential of reducing sugars. Corn flakes induced greater liberation of reducing sugars as compared to the others. Thin layer chromatography of the reaction end products showed that the hydrolysis of cassava flour liberated maltooligosaccharides, but cassava flour and corn, rye, oats and barley flakes were hydrolyzed to glucose. These results suggested the presence of glucoamylase and α-amylase as part of the enzymatic pool of A. phoencis.

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Evaluation of the growth and sporulation of different entomopathogenic fungi in different liquid and solid media at varied concentrations

International Journal of Bioassays ◽

10.21746/ijbio.2017.08.003 ◽

2017 ◽

Vol 6 (8) ◽

pp. 5459

Author(s):

Chandra Teja K. ◽

Rahman S. J.

Keyword(s):

Entomopathogenic Fungi ◽

Large Scale ◽

Insect Pests ◽

Culture Media ◽

Virulent Strain ◽

Carbon Sources ◽

Nitrogen Sources ◽

Maximum Growth ◽

Nutritional Requirements ◽

Virulent Strains

Entomopathogenic fungi like Beauveria bassiana, Metarhizium anisopliae and Lecanicillium lecanii are used in biological control of agricultural insect pests. Their specific mode of action makes them an effective alternative to the chemical Insecticides. Virulent strains of Entomopathogenic fungi are effectively formulated and used as bio-insecticides world-wide. Amenable and economical multiplication of a virulent strain in a large scale is important for them to be useful in the field. Culture media plays a major role in the large-scale multiplication of virulent strains of Entomopathogens. Different substrates and media components are being used for this purpose. Yet, each strain differs in its nutritional requirements for the maximum growth and hence it is necessary to standardize the right components and their optimum concentrations in the culture media for a given strain of Entomopathogen. In the current study, three different nitrogen sources and two different carbon sources were tried to standardize the mass multiplication media for seven test isolates of Entomopathogenic fungi. A study was also conducted to determine the ideal grain media for the optimum conidial yields of the test isolates. Yeast extract was found to be the best Nitrogen source for the isolates. The isolates tested, differed in their nutritional requirements and showed variation in the best nitrogen and carbon sources necessary for their growth. Variation was also found in the optimum concentration of both the ingredients for the growth and sporulation of the isolates. In the solid-state fermentation study, rice was found to be the best grain for the growth of most of the fungi followed by barley. The significance of such a study in the development of an effective Myco-insecticide is vital and can be successfully employed in agriculture is discussed.

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Ecophysiology of Freshwater Verrucomicrobia Inferred from Metagenome-Assembled Genomes

mSphere ◽

10.1128/msphere.00277-17 ◽

2017 ◽

Vol 2 (5) ◽

Cited By ~ 33

Author(s):

Shaomei He ◽

Sarah L. R. Stevens ◽

Leong-Keat Chan ◽

Stefan Bertilsson ◽

Tijana Glavina del Rio ◽

...

Keyword(s):

Electron Transfer ◽

Potential Role ◽

Carbon Sources ◽

Genomic Analysis ◽

Distribution Patterns ◽

Eutrophic Lake ◽

Genomic Diversity ◽

Extracellular Electron Transfer ◽

Different Origins ◽

Encoding Genes

ABSTRACT Freshwater Verrucomicrobia spp. are cosmopolitan in lakes and rivers, and yet their roles and ecophysiology are not well understood, as cultured freshwater Verrucomicrobia spp. are restricted to one subdivision of this phylum. Here, we greatly expanded the known genomic diversity of this freshwater lineage by recovering 19 Verrucomicrobia draft genomes from 184 metagenomes collected from a eutrophic lake and a humic bog across multiple years. Most of these genomes represent the first freshwater representatives of several Verrucomicrobia subdivisions. Genomic analysis revealed Verrucomicrobia to be potential (poly)saccharide degraders and suggested their adaptation to carbon sources of different origins in the two contrasting ecosystems. We identified putative extracellular electron transfer genes and so-called “Planctomycete-specific” cytochrome c-encoding genes and identified their distinct distribution patterns between the lakes/layers. Overall, our analysis greatly advances the understanding of the function, ecophysiology, and distribution of freshwater Verrucomicrobia, while highlighting their potential role in freshwater carbon cycling. Microbes are critical in carbon and nutrient cycling in freshwater ecosystems. Members of the Verrucomicrobia are ubiquitous in such systems, and yet their roles and ecophysiology are not well understood. In this study, we recovered 19 Verrucomicrobia draft genomes by sequencing 184 time-series metagenomes from a eutrophic lake and a humic bog that differ in carbon source and nutrient availabilities. These genomes span four of the seven previously defined Verrucomicrobia subdivisions and greatly expand knowledge of the genomic diversity of freshwater Verrucomicrobia. Genome analysis revealed their potential role as (poly)saccharide degraders in freshwater, uncovered interesting genomic features for this lifestyle, and suggested their adaptation to nutrient availabilities in their environments. Verrucomicrobia populations differ significantly between the two lakes in glycoside hydrolase gene abundance and functional profiles, reflecting the autochthonous and terrestrially derived allochthonous carbon sources of the two ecosystems, respectively. Interestingly, a number of genomes recovered from the bog contained gene clusters that potentially encode a novel porin-multiheme cytochrome c complex and might be involved in extracellular electron transfer in the anoxic humus-rich environment. Notably, most epilimnion genomes have large numbers of so-called “Planctomycete-specific” cytochrome c-encoding genes, which exhibited distribution patterns nearly opposite to those seen with glycoside hydrolase genes, probably associated with the different levels of environmental oxygen availability and carbohydrate complexity between lakes/layers. Overall, the recovered genomes represent a major step toward understanding the role, ecophysiology, and distribution of Verrucomicrobia in freshwater. IMPORTANCE Freshwater Verrucomicrobia spp. are cosmopolitan in lakes and rivers, and yet their roles and ecophysiology are not well understood, as cultured freshwater Verrucomicrobia spp. are restricted to one subdivision of this phylum. Here, we greatly expanded the known genomic diversity of this freshwater lineage by recovering 19 Verrucomicrobia draft genomes from 184 metagenomes collected from a eutrophic lake and a humic bog across multiple years. Most of these genomes represent the first freshwater representatives of several Verrucomicrobia subdivisions. Genomic analysis revealed Verrucomicrobia to be potential (poly)saccharide degraders and suggested their adaptation to carbon sources of different origins in the two contrasting ecosystems. We identified putative extracellular electron transfer genes and so-called “Planctomycete-specific” cytochrome c-encoding genes and identified their distinct distribution patterns between the lakes/layers. Overall, our analysis greatly advances the understanding of the function, ecophysiology, and distribution of freshwater Verrucomicrobia, while highlighting their potential role in freshwater carbon cycling.

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Impact of Different Carbon Sources on the in vitro Growth and Viability of Escherichia coli (SUBE01) and Salmonella spp. (SUBS01) Cells

Bangladesh Journal of Microbiology ◽

10.3329/bjm.v32i0.28476 ◽

2016 ◽

pp. 39-44

Author(s):

Ifra Tun Nur ◽

Jannatun Tahera ◽

Md Sakil Munna ◽

M Majibur Rahman ◽

Rashed Noor

Keyword(s):

Escherichia Coli ◽

Bacterial Growth ◽

Culture Media ◽

Bacterial Species ◽

Carbon Sources ◽

Growth Dynamics ◽

Luria Bertani ◽

Tween 20 ◽

Salmonella Spp

With a previous observation of Escherichia coli growth cessation along with temperature variation within three different bacteriological culture media (nutrient agar, Luria-Bertani agar and minimal agar), current investigation further depicted on the possible growth dynamics of Escherichia coli (SUBE01) and Salmonella (SUBS01) growth and viability upon supplementation of different carbon sources (dextrose, sucrose, lactose, glycerol and tween 20) at 37°C under the aeration of 100 rpm. Viability of the tested bacterial species was assessed through the enumeration of the colony forming unit (cfu) appeared upon prescribed incubation for 12-24 hours on different agar plates consisting of the above mentioned carbon sources. Besides, to inspect the cellular phenotypic changes, morphological observations were conducted under the light microscope. Variations in bacterial growth (either growth acceleration or cessation) were further noticed through the spot tests on the agar plates. Considerable shortfalls in the culturable cells of E. coli and Salmonella spp. were noted in the minimal media separately consisting of sucrose, lactose, glycerol or tween 20 while an opposite impact of accelerated growth was noticed in the media supplied with dextrose. The data revealed a hierarchy of consequence of carbon sources as nutrient generators whereby the favourable bacterial growth and survival order of the carbon sources was estimated as dextrose > glycerol > lactose > tween 20 > sucrose.Bangladesh J Microbiol, Volume 32, Number 1-2,June-Dec 2015, pp 39-44

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Identificación, establecimiento in vitro y análisis fitoquímico preliminar de especies silvestres de ñame (Dioscorea spp.) empleadas con fines medicinales

Revista Colombiana de Biotecnología ◽

10.15446/rev.colomb.biote.v17n1.50711 ◽

2015 ◽

Vol 17 (1) ◽

pp. 9-17 ◽

Cited By ~ 3

Author(s):

Víctor Andrés Ramos Duarte ◽

Silvia Lizette Bustamante, R. ◽

Javier Rincón Velandia ◽

Maritza Adelina Rojas Cardozo ◽

Lauren Raz ◽

...

Keyword(s):

Culture Media ◽

Phytochemical Analysis ◽

Extraction Solvent ◽

Palabras Clave ◽

Edible Species ◽

Medicinal Use ◽

Advanced Analysis ◽

Layer Chromatography ◽

Wild Yam

Título en ingles: Identification, in vitro establishment and preliminary phytochemical analysis of wild yam (Dioscorea spp.) used for medicinal purposesTítulo corto: Identificación, establecimiento in vitro y análisis fitoquímico preliminar de especies silvestres de ñameResumen: Tubérculos del género Dioscorea comercializados con fines medicinales, fueron recolectados con el propósito de lograr su establecimiento a condiciones in vitro. Previamente se lograron identificar taxonómicamente las especies y por medio de análisis fitoquímicos demostrar su potencial farmacéutico. El material recolectado fue identificado como Dioscorea coriacea, D. lehmannii, D. meridensis, D. polygonoides y una especie comestible D. trifida. Tubérculos recolectados de centros de acopio y traídos de campo fueron lavados, desinfectados, asperjados con Ácido Giberélico (AG3) y sembrados en sustrato BM-2®, en invernadero a 18°C día y 10°C noche. Los tubérculos completos o por secciones fueron almacenados en bolsas herméticas a temperatura ambiente. Posteriormente se desinfectó material vegetal de las especies D. coriacea, D. lehmannii, D. meridensis y D polygonoides, seleccionando explantes de brotes sanos (D. coriacea / laboratorio) para su establecimiento. Se evaluaron tres medios de cultivo para establecimiento, el que presentó los mejores resultados fue Medio Murashige & Skoog (1962) suplementado con BAP 1 mL/L, AG3 1 mL/L y Putrescina 2 mL/L. Para la extracción y análisis de metabolitos secundarios se utilizaron tubérculos de D. coriacea, D. lehmannii y D. polygonoides, empleando como solvente de extracción metanol. Se encontró mayor concentración de extracto vegetal en D. coriacea (54%), y mediante cromatografía en capa delgada (CCD), se confirmó la presencia de saponinas, que resultó mayor en comparación con D. polygonoides especie reconocida por su alto contenido de saponinas. Estos resultados permitirán realizar análisis más avanzados de los compuestos presentes y plantear su propagación masiva en condiciones in vitro. Palabras clave: diosgenina, micropropagación, ñame silvestre, cultivo de tejidos vegetales, saponinas, fitoquímica.Abstract: Wild tubers of the genus Dioscorea sold for medicinal use were collected for the purpose of achieving its establishment under in vitro conditions. First we taxonomically identified the species and through phytochemical analysis demonstrated pharmaceutical potential. The material collected was identified as Dioscorea coriacea, D. lehmannii, D. meridensis, D. polygonoides and the edible species D. trifida. Tubers collected from wholesale distributors and from the field were washed, disinfected, sprayed with Gibberellic Acid (GA3) and planted in substrate BM-2®, in a greenhouse at 18 ° C during the day and 10 ° C overnight. Whole tubers or sections thereof were stored in sealed bags at room temperature. Subsequently plant material of the species D. coriacea, D. lehmannii, D. meridensis and D. polygonoides was disinfected and healthy buds (D. coriacea / laboratory) were selected for in vitro establishment. Three different culture media were evaluated for establishment; that which presented the best results was the Murashige & Skoog (1962) medium, supplemented with BAP 1 mL / L, GA3 1 mL / L and Putrescin 2 mL / L. For the collection and analysis of secondary metabolites, tubers of D. coriacea, D. lehmannii and D. polygonoides were used, using methanol as the extraction solvent. The highest concentration of plant extract, 54%, was found in D. coriacea, a higher value than that of D. polygonoides, which had been reported previously; the presence of saponins was confirmed by thin layer chromatography (TLC). These results will enable more advanced analysis of the present compounds and enhance their mass propagation under in vitro conditions.Key words: diosgenin, micropropagation, wild yam, tissue culture, saponins, phitochemistry.Recibido: agosto 20 de 2014 Aprobado: abril 20 de 2015

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Valorization of agro-industrial wastes to produce hydrolytic enzymes by fungal solid-state fermentation

Waste Management & Research ◽

10.1177/0734242x18798699 ◽

2018 ◽

Vol 37 (2) ◽

pp. 149-156 ◽

Cited By ~ 12

Author(s):

C. Marzo ◽

A.B. Díaz ◽

I. Caro ◽

A. Blandino

Keyword(s):

Solid State ◽

Solid State Fermentation ◽

Reducing Sugars ◽

Raw Materials ◽

Hydrolytic Enzymes ◽

Industrial Wastes ◽

Added Value ◽

Orange Peels ◽

Enzyme Cocktail ◽

Hydrolysis Of

Nowadays, significant amounts of agro-industrial wastes are discarded by industries; however, they represent interesting raw materials for the production of high-added value products. In this regard, orange peels (ORA) and exhausted sugar beet cossettes (ESBC) have turned out to be promising raw materials for hydrolytic enzymes production by solid state fermentation (SSF) and also a source of sugars which could be fermented to different high-added value products. The maximum activities of xylanase and exo-polygalacturonase (exo-PG) measured in the enzymatic extracts obtained after the SSF of ORA were 31,000 U·kg-1 and 17,600 U·kg-1, respectively; while for ESBC the maximum values reached were 35,000 U·kg-1 and 28,000 U·kg-1, respectively. The enzymatic extracts obtained in the SSF experiments were also employed for the hydrolysis of ORA and ESBC. Furthermore, it was found that extracts obtained from SSF of ORA, supplemented with commercial cellulase, were more efficient for the hydrolysis of ORA and ESBC than a commercial enzyme cocktail typically used for this purpose. In this case, maximum reducing sugars concentrations of 57 and 47 g·L-1 were measured after the enzymatic hydrolysis of ESBC and ORA, respectively.

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NontypeableHaemophilus influenzaeHas Evolved Preferential Use ofN-Acetylneuraminic Acid as a Host Adaptation

mBio ◽

10.1128/mbio.00422-19 ◽

2019 ◽

Vol 10 (3) ◽

Cited By ~ 5

Author(s):

Preston S. K. Ng ◽

Christopher J. Day ◽

John M. Atack ◽

Lauren E. Hartley-Tassell ◽

Linda E. Winter ◽

...

Keyword(s):

Sialic Acid ◽

Antibody Response ◽

Immune Evasion ◽

Biofilm Formation ◽

Culture Media ◽

Carbon Sources ◽

Bacterial Pathogen ◽

Catalytic Efficiency ◽

Human Antibody ◽

Acetylneuraminic Acid

ABSTRACTNontypeableHaemophilus inﬂuenzae(NTHi) is a Gram-negative bacterial pathogen that is adapted exclusively to human hosts. NTHi utilizes sialic acid from the host as a carbon source and as a terminal sugar on the outer membrane glycolipid lipooligosaccharide (LOS). Sialic acid expressed on LOS is critical in NTHi biofilm formation and immune evasion. There are two major forms of sialic acids in most mammals,N-acetylneuraminic acid (Neu5Ac) andN-glycolylneuraminic acid (Neu5Gc), the latter of which is derived from Neu5Ac. Humans lack the enzyme to convert Neu5Ac to Neu5Gc and do not express Neu5Gc in normal tissues; instead, Neu5Gc is recognized as a foreign antigen. A recent study showed that dietary Neu5Gc can be acquired by NTHi colonizing humans and then presented on LOS, which acts as an antigen for the initial induction of anti-Neu5Gc antibodies. Here we examined Neu5Gc uptake and presentation on NTHi LOS. We show that, although Neu5Gc and Neu5Ac are utilized equally well as sole carbon sources, Neu5Gc is not incorporated efficiently into LOS. When equal amounts of Neu5Gc and Neu5Ac are provided in culture media, there is ∼4-fold more Neu5Ac incorporated into LOS, suggesting a bias in a step of the LOS biosynthetic pathway. CMP-Neu5Ac synthetase (SiaB) was shown to have ∼4,000-fold-higher catalytic efficiency for Neu5Ac than for Neu5Gc. These data suggest that NTHi has adapted preferential utilization of Neu5Ac, thus avoiding presentation of the nonhuman Neu5Gc in the bacterial cell surface. The selective pressure for this adaptation may represent the human antibody response to the Neu5Gc xenoantigen.IMPORTANCEHost-adapted bacterial pathogens such as NTHi cannot survive out of their host environment and have evolved host-specific mechanisms to obtain nutrients and evade the immune response. Relatively few of these host adaptations have been characterized at the molecular level. NTHi utilizes sialic acid as a nutrient and also incorporates this sugar into LOS, which is important in biofilm formation and immune evasion. In the present study, we showed that NTHi has evolved to preferentially utilize the Neu5Ac form of sialic acid. This adaptation is due to the substrate preference of the enzyme CMP-Neu5Ac synthetase, which synthesizes the activated form of Neu5Ac for macromolecule biosynthesis. This adaptation allows NTHi to evade killing by a human antibody response against the nonhuman sialic acid Neu5Gc.

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Renewable Biodiesel Production from Oleaginous Yeast Biomass Using Industrial Wastes

E3S Web of Conferences ◽

10.1051/e3sconf/202014103010 ◽

2020 ◽

Vol 141 ◽

pp. 03010

Author(s):

Sasithorn Kongruang ◽

Sittiruk Roytrakul ◽

Malinee Sriariyanun

Keyword(s):

Fatty Acid ◽

Second Generation ◽

Carbon Sources ◽

Morphological Characteristics ◽

Rhodotorula Glutinis ◽

Industrial Wastes ◽

Biodiesel Production ◽

Yeast Strains ◽

Fatty Acid Profiling ◽

Carbon Substrates

The accumulation lipid from oleaginous microorganisms is recognized as a second generation fuel. Biooil is known to as intracellular product of oily yeast utilizing various carbon substrates and converting different quantities of lipids in the form of triacylglycerols. This second generation fuel can be used to make biodiesel via a transesterification process. This study investigated the morphological characteristics of eight strains of Thai oleaginous yeasts via microscopy and analyzed the fatty acid profiling of yeasts cultured in three carbon sources: glucose, sugar cane molasses and crude glycerol in order to estimate biodiesel properties. To approach this goal, batch fermentations were used to culture eight yeast strains, Rhodosporidium toruloides TISTR 5123, TISTR 5154, TISTR 5149, Yarrowia lipolytica TISTR 5054, TISTR 5151, TISTR 5621, Rhodotorula glutinis TISTR 5159 and Rhodotorula graminis TISTR 5124 for 96 h under 30°C at 250 rpm. Result revealed that eight yeast strains contained significant amounts of fatty acids and lipids and accumulated mainly palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C 18:1) and linoleic acid (C18:2), and they are suitable for the production of biodiesel. Fatty acid productions and profiles indicated that these yeast strains can be potentially used as the triacylglycerols producers for biodiesel production.

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Primary Human Fibroblasts in Culture Switch to a Myofibroblast-Like Phenotype Independently of TGF Beta

Cells ◽

10.3390/cells8070721 ◽

2019 ◽

Vol 8 (7) ◽

pp. 721 ◽

Cited By ~ 7

Author(s):

Ulrike Baranyi ◽

Birgitta Winter ◽

Alfred Gugerell ◽

Balazs Hegedus ◽

Christine Brostjan ◽

...

Keyword(s):

Culture Media ◽

Smooth Muscle Actin ◽

Human Fibroblasts ◽

Calf Serum ◽

Culture Conditions ◽

Alpha Smooth Muscle Actin ◽

Cultured Fibroblasts ◽

And Migration ◽

Phenotype Formation ◽

Different Origins

Fibroblasts are the prevalent cell type and main source for extracellular matrix (ECM) in connective tissue. Depending on their origin, fibroblasts play a central role in non-pathological tissue remodeling and disease like fibrosis. This study examined the effect of established culture conditions of primary human fibroblasts, from different origins on the myofibroblast-like phenotype formation. We isolated primary human fibroblasts from aortic adventitia, lung, juvenile- and adult skin and investigated the expression levels of CD90, alpha smooth muscle actin (αSMA) and procollagen I under different concentrations of fetal calf serum (FCS) and ascorbic acid (AA) in culture media by immunoblot and immunofluorescence assays. Furthermore, we determined the viability using XTT and migration/wound healing in scratch assays. Collagen 1 secretion was quantified by specific ELISA. Primary human fibroblasts show in part a myofibroblast-like phenotype even without addition of FCS. Supplemented AA reduces migration of cultured fibroblasts with no or low concentrations of FCS. Furthermore, AA and higher concentrations of FCS in culture media lead to higher levels of collagen 1 secretion instead of procollagen I accumulation. This study provides evidence for a partial switch of primary human fibroblasts of different origin to a myofibroblast-like phenotype under common culture conditions.

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The synthesis, separation, and identification of the methyl ethers of arabinose and their derivatives

Canadian Journal of Chemistry ◽

10.1139/v67-050 ◽

1967 ◽

Vol 45 (3) ◽

pp. 275-290 ◽

Cited By ~ 32

Author(s):

S. C. Williams ◽

J. K. N. Jones

Keyword(s):

Reducing Sugars ◽

Reducing Sugar ◽

The Other ◽

Partition Chromatography ◽

Ring Form ◽

Optical Rotations ◽

Layer Chromatography ◽

Derivatives Of ◽

Spray Reagents

A study has been made of various methods available for the identification and separation of the methyl ethers of arabinose. Gas–liquid partition chromatography has been used to separate the acetylated glycosides and the acetylated alditols of the methyl ethers of arabinose. All of the methyl ethers of arabinopyranose and arabinofuranose have been separated by paper chromatography. Several spray reagents have been used to distinguish between those methyl ethers with similar rates of movement. Thin-layer chromatography has been used to separate the methyl glycosides, acetylated methyl glycosides, and glycitols of the methyl ethers of arabinose, as well as the methyl ethers of the reducing sugar. The optical rotations of the reducing sugars and of the methyl glycosides of the methyl ethers of arabinose provide information about the ring form and, in the case of the glycosides, about the anomer present. The rotations of the acetylated and unacetylated O-methyl arabinitols aid in the determination of the position of the methyl substitutents. In connection with this study, all of the mono-O-methyl and tri-O-methyl, and most of the di-O-methyl ethers of arabinose have been synthesized. New syntheses have been devised for 4-O-methyl and 2,3-di-O-methyl arabinose, and the other sugars have been synthesized by known or partially revised syntheses. During this work, previously unreported derivatives of these sugars have been prepared.

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Effect of culture media and pH on the biomass production and biocontrol efficacy of aMetschnikowia pulcherrimastrain to be used as a biofungicide for postharvest disease control

Canadian Journal of Microbiology ◽

10.1139/w09-117 ◽

2010 ◽

Vol 56 (2) ◽

pp. 128-137 ◽

Cited By ~ 50

Author(s):

D. Spadaro ◽

A. Ciavorella ◽

Z. Dianpeng ◽

A. Garibaldi ◽

M. L. Gullino

Keyword(s):

Biomass Production ◽

Yeast Extract ◽

Culture Media ◽

Carbon Sources ◽

Ph Control ◽

Cell Number ◽

Penicillium Expansum ◽

Postharvest Disease ◽

Yeast Growth ◽

Nutrient Sources

Few strains of Metschnikowia pulcherrima (Pitt) M.W. Miller are under development for control of postharvest pathogens on fruit. A substrate was developed to optimize the biomass production of M. pulcherrima strain BIO126. Different complex nutrient sources, with or without pH control, were tested. Growth in yeast extract provided at concentrations ≥30 g·L–1yielded the highest biomass. The addition of two carbon sources, d-mannitol and l-sorbose, at 5 g·L–1each, significantly improved yeast growth. The greatest amount of yeast growth occurred when pH values of the medium ranged from 5.0 to 7.5. A combination of yeast extract, d-mannitol, and l-sorbose (YEMS), probably with diauxic utilization, showed a synergistic effect, widening the exponential phase (maximum specific growth rate of 0.45 h–1) and increasing the final cell number (1.5 × 109cells·mL–1) and dry biomass (6.0 g·L–1) in well-controlled batch fermentation. In efficacy trials on ‘Golden Delicious’ apples, M. pulcherrima grown in YEMS effectively reduced incidence and severity of Botrytis cinerea (51.1% and 70.8%, respectively) and Penicillium expansum (41.7% and 14.0%, respectively). Also on ‘Gala’ apples, the best reduction of grey and blue mould incidence was obtained with cells grown in YEMS (58.1% and 50.5%, respectively).

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