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1.
Bioelectrochemistry ; 156: 108609, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-37995505

RESUMEN

Lignin is the most important natural source of aromatic compounds. The valorisation of lignin into aromatics requires fractionation steps that can be catalysed by ligninolytic enzymes. However, one of the main limitations of biological lignin fractionation is the low efficiency of biocatalysts; it is therefore crucial to enhance or to identify new ligninolytic enzymes. Currently, the screening of ligninolytic activities on lignin polymers represents a technological bottenleck and hinders the characterization and the discovery of efficient ligninolytic biocatalysts. An efficient and fast method for the measurement of such enzymatic activities is therefore required. In this work, we present a new electrochemical tool based on lignin-coated paper electrodes for the detection and the characterization of ligninolytic activity. The suitability of this method is demonstrated using a catalase-peroxidase isolated from Thermobacillus xylanilyticus.


Asunto(s)
Lignina , Peroxidasas , Lacasa , Lignina/química , Peroxidasa , Compuestos Orgánicos/química
2.
Lett Appl Microbiol ; 76(8)2023 Aug 02.
Artículo en Inglés | MEDLINE | ID: mdl-37481695

RESUMEN

Polyhydroxyalkanoates (PHAs) are bioplastics that can serve as substitutes for petroleum-based plastics with the advantages of being biodegradable, biocompatible, and biobased. The microbial production of polyhydroxyalkanoates is generally conducted in the presence of sugar mixes rich in monosaccharides. In this study, molecular and cultural approaches based on forest soils enriched with hydrocarbon complexes led to the identification and isolation of microbial strains affiliated with Paraburkholderia sp. that dominated the microbial communities that are recognized among the top polyhydroxyalkanoates producers. The genome sequencing of those isolated affiliated strains showed that compared to the reference type strain of their species, they harbored more gene copies of the enzymes involved in PHB synthesis. The microbial conversion of sugar mixes for the newly isolated strains showed a higher PHB production (g/L) and content (%) than was exhibited by the reference strain type of that genus Paraburkholderia for PHB production (P. sacchari LMG 19450T).


Asunto(s)
Polihidroxialcanoatos , Biopolímeros , Plásticos , Azúcares
3.
Mycologia ; 115(5): 579-601, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37358885

RESUMEN

Neofusicoccum parvum is one of the most aggressive Botryosphaeriaceae species associated with grapevine trunk diseases. This species may secrete enzymes capable of overcoming the plant barriers, leading to wood colonization. In addition to their roles in pathogenicity, there is an interest in taking advantage of N. parvum carbohydrate-active enzymes (CAZymes), related to plant cell wall degradation, for lignocellulose biorefining. Furthermore, N. parvum produces toxic secondary metabolites that may contribute to its virulence. In order to increase knowledge on the mechanisms underlying pathogenicity and virulence, as well as the exploration of its metabolism and CAZymes for lignocellulose biorefining, we evaluated the N. parvum strain Bt-67 capacity in producing lignocellulolytic enzymes and secondary metabolites when grown in vitro with two lignocellulosic biomasses: grapevine canes (GP) and wheat straw (WS). For this purpose, a multiphasic study combining enzymology, transcriptomic, and metabolomic analyses was performed. Enzyme assays showed higher xylanase, xylosidase, arabinofuranosidase, and glucosidase activities when the fungus was grown with WS. Fourier transform infrared (FTIR) spectroscopy confirmed the lignocellulosic biomass degradation caused by the secreted enzymes. Transcriptomics indicated that the N. parvum Bt-67 gene expression profiles in the presence of both biomasses were similar. In total, 134 genes coding CAZymes were up-regulated, where 94 of them were expressed in both biomass growth conditions. Lytic polysaccharide monooxygenases (LPMOs), glucosidases, and endoglucanases were the most represented CAZymes and correlated with the enzymatic activities obtained. The secondary metabolite production, analyzed by high-performance liquid chromatography-ultraviolet/visible spectophotometry-mass spectrometry (HPLC-UV/Vis-MS), was variable depending on the carbon source. The diversity of differentially produced metabolites was higher when N. parvum Bt-67 was grown with GP. Overall, these results provide insight into the influence of lignocellulosic biomass on virulence factor expressions. Moreover, this study opens the possibility of optimizing the enzyme production from N. parvum with potential use for lignocellulose biorefining.


Asunto(s)
Ascomicetos , Biomasa , Factores de Virulencia , Polisacáridos
4.
Fungal Biol ; 127(5): 1010-1031, 2023 05.
Artículo en Inglés | MEDLINE | ID: mdl-37142361

RESUMEN

The Botryosphaeriaceae family comprises numerous fungal pathogens capable of causing economically meaningful diseases in a wide range of crops. Many of its members can live as endophytes and turn into aggressive pathogens following the onset of environmental stress events. Their ability to cause disease may rely on the production of a broad set of effectors, such as cell wall-degrading enzymes, secondary metabolites, and peptidases. Here, we conducted comparative analyses of 41 genomes representing six Botryosphaeriaceae genera to provide insights into the genetic features linked to pathogenicity and virulence. We show that these Botryosphaeriaceae genomes possess a large diversity of carbohydrate-active enzymes (CAZymes; 128 families) and peptidases (45 families). Botryosphaeria, Neofusicoccum, and Lasiodiplodia presented the highest number of genes encoding CAZymes involved in the degradation of the plant cell wall components. The genus Botryosphaeria also exhibited the highest abundance of secreted CAZymes and peptidases. Generally, the secondary metabolites gene cluster profile was consistent in the Botryosphaeriaceae family, except for Diplodia and Neoscytalidium. At the strain level, Neofusicoccum parvum NpBt67 stood out among all the Botryosphaeriaceae genomes, presenting a higher number of secretome constituents. In contrast, the Diplodia strains showed the lowest richness of the pathogenicity- and virulence-related genes, which may correlate with their low virulence reported in previous studies. Overall, these results contribute to a better understanding of the mechanisms underlying pathogenicity and virulence in remarkable Botryosphaeriaceae species. Our results also support that Botryosphaeriaceae species could be used as an interesting biotechnological tool for lignocellulose fractionation and bioeconomy.


Asunto(s)
Ascomicetos , Virulencia/genética , Enfermedades de las Plantas/microbiología
5.
Appl Microbiol Biotechnol ; 107(1): 201-217, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36418542

RESUMEN

Lignocellulosic biomass is rich in lignins, which represent a bottomless natural source of aromatic compounds. Due to the high chemical complexity of these aromatic polymers, their biological fractionation remains challenging for biorefinery. The production of aromatics from the biological valorization of lignins requires the action of ligninolytic peroxidases and laccases produced by fungi and bacteria. Therefore, identification of efficient ligninolytic enzymes with high stability represents a promising route for lignins biorefining. Our strategy consists in exploiting the enzymatic potential of the thermophilic bacterium Thermobacillus xylanilyticus to produce robust and thermostable ligninolytic enzymes. In this context, a gene encoding a putative catalase-peroxidase was identified from the bacterial genome. The present work describes the production of the recombinant protein, its biochemical characterization, and ligninolytic potential. Our results show that the catalase-peroxidase from T. xylanilyticus is thermostable and exhibits catalase-peroxidase and manganese peroxidase activities. The electrochemical characterization using intermittent pulse amperometry showed the ability of the enzyme to oxidize small aromatic compounds derived from lignins. This promising methodology allows the fast screening of the catalase-peroxidase activity towards small phenolic molecules, suggesting its potential role in lignin transformation. KEY POINTS: • Production and characterization of a new thermostable bacterial catalase-peroxidase • The enzyme is able to oxidize many phenolic monomers derived from lignins • Intermittent pulse amperometry is promising to screen ligninolytic enzyme.


Asunto(s)
Lignina , Peroxidasa , Lignina/metabolismo , Catalasa , Peroxidasas/genética , Peroxidasas/metabolismo , Fenoles
6.
FEMS Microbiol Lett ; 369(1)2022 11 11.
Artículo en Inglés | MEDLINE | ID: mdl-36302146

RESUMEN

Streptomyces coelicolor A3(2) is considered as the model strain among the Streptomyces and has the capacity to produce several natural molecules. Our hypothesis was that cultivation of the strain onto a complex carbon source such as wheat bran (WB) would induce the production of various secondary metabolites due to the presence of complex polysaccharides. A multiapproach has been performed in order to investigate: (1) whether that strain could degrade lignocellulose; (2) which enzymatic and metabolic pathways secondary were over-expressed when grown on WB. The transcriptomic approach showed the expression of several CAZymes significantly expressed when grown on WB such as endoglucanases (encoding for GH74, GH5_8, and GH12) and xylanases (GH11 and CE4 encoding for respectively endo-1,4-beta-xylanase and an acetyl-xylan esterase). Enzymatic activities showed an expression of xylanase (115.3 ± 32.2 mUI/ml) and laccase-peroxidase (101.5 ± 10.9 mUI/ml) during WB degradation by S. coelicolor A3(2). Metabolomics showed that the production of secondary metabolites differed between growth on either glucose or WB as carbon source, which may be correlated to the complexity of carbon compounds within WB, which are similar to the ones encountered in soils and should represent more the in situ carbon conditions which Streptomyces might face off. This opens opportunities for the bioproduction of molecules of interest from WB.


Asunto(s)
Streptomyces coelicolor , Streptomyces , Streptomyces coelicolor/metabolismo , Transcriptoma , Lignina/metabolismo , Streptomyces/metabolismo , Carbono/metabolismo
7.
Artículo en Inglés | MEDLINE | ID: mdl-36048630

RESUMEN

Strain RHZ10T was isolated from an oak rhizosphere sampled in Reims, France, and characterized to assess its taxonomy. Based on 16S rRNA gene sequence similarity, strain RHZ10T was affiliated to the genus Streptomyces and the closest species were Streptomyces anulatus NRRL B-2000T and Streptomyces pratensis ch24T. Average nucleotide identity and digital DNA-DNA hybridization values were 77.3-92.4 % and 23.0-50.9 %, respectively, when compared to the type strains of fully sequenced related species having a 16S rRNA gene sequence similarity over 98 %. These data suggested that strain RHZ10T represented a novel species within the genus Streptomyces. The genome of RHZ10T was 8.0 Mbp long, had 7  894 predicted coding genes, and a G+C content of 71.7 mol%. Cultures of RHZ10T on ISP 2 medium mostly led to the production a green pigmentation of the core of its colonies in the vegetative mycelium, surrounded by white pigmentation of the aerial mycelium. The main fatty acids of RHZ10T were anteiso-C15 : 0, iso-C16 : 0, anteiso-C17 : 0 and C16 : 0. Polar lipids were phosphatidylethanolamine, diphosphatidylglycerol, unidentified lipids, unidentified phospholipids, unidentified aminolipids and unidentified glycolipids. Its main quinones were MK-9(H6) (69.3 %), MK-9(H4) (17.3 %) and MK-9(H8) (17.0%). Phylogenetic, physiological and chemotaxonomic studies clearly supported that strain RHZ10T represents a novel species within the genus Streptomyces, for which the name Streptomyces durocortorensis sp. nov. is proposed and the type strain is RHZ10T (=DSM 112634T=LMG 32187T=CIP 111907T).


Asunto(s)
Quercus , Streptomyces , Técnicas de Tipificación Bacteriana , Composición de Base , ADN Bacteriano/genética , Ácidos Grasos/química , Fosfolípidos , Filogenia , ARN Ribosómico 16S/genética , Rizosfera , Análisis de Secuencia de ADN , Microbiología del Suelo
8.
Braz J Microbiol ; 53(4): 1829-1842, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36040685

RESUMEN

The microorganisms living on the phyllosphere (the aerial part of the plants) are in contact with the lignocellulosic plant cell wall and might have a lignocellulolytic potential. We isolated a Saccharibacillus strain (Saccharibacillus WB17) from wheat bran phyllosphere and its cellulolytic and hemicellulolytic potential was investigated during growth onto wheat bran. Five other type strains from that genus selected from databases were also cultivated onto wheat bran and glucose. Studying the chemical composition of wheat bran residues by FTIR after growth of the six strains showed an important attack of the stretching C-O vibrations assigned to polysaccharides for all the strains, whereas the C = O bond/esterified carboxyl groups were not impacted. The genomic content of the strains showed that they harbored several CAZymes (comprised between 196 and 276) and possessed four of the fifth modules reflecting the presence of a high diversity of enzymes families. Xylanase and amylase activities were the most active enzymes with values reaching more than 4746 ± 1400 mIU/mg protein for the xylanase activity in case of Saccharibacillus deserti KCTC 33693 T and 452 ± 110 mIU/mg protein for the amylase activity of Saccharibacillus WB17. The total enzymatic activities obtained was not correlated to the total abundance of CAZyme along that genus. The Saccharibacillus strains harbor also some promising proteins in the GH30 and GH109 modules with potential arabinofuranosidase and oxidoreductase activities. Overall, the genus Saccharibacillus and more specifically the Saccharibacillus WB17 strain represent biological tools of interest for further biotechnological applications.


Asunto(s)
Bacillales , Fibras de la Dieta , Polisacáridos Bacterianos , Amilasas , Fibras de la Dieta/microbiología , Genómica , Filogenia , Bacillales/clasificación , Bacillales/aislamiento & purificación , Polisacáridos Bacterianos/química
9.
Bioprocess Biosyst Eng ; 45(8): 1359-1370, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-35881245

RESUMEN

Thermobacillus xylanilyticus is a thermophilic and hemicellulolytic bacterium of interest for the production of thermostable hemicellulases. Enzymes' production by this bacterium is challenging, because the proliferation of a cheating subpopulation of cells during exponential growth impairs the production of xylanase after serial cultivations. Accordingly, a strategy of successive cultivations with cells transfers in stationary phase and the use of wheat bran and wheat straw as carbon sources were tested. The ratio between subpopulations and their corresponding metabolic activities were studied by flow cytometry and the resulting hemicellulases production (xylanase, acetyl esterase and ß-xylosidase) followed. During serial cultivations, the results pointed out an increase of the enzymatic activities. On xylan, compared to the first cultivation, the xylanase activity increases by 7.15-fold after only four cultivations. On the other hand, the debranching activities were increased by 5.88-fold and 57.2-fold on wheat straw and by 2.77-fold and 3.34-fold on wheat bran for ß-xylosidase and acetyl esterase, respectively. The different enzymatic activities then stabilized, reached a plateau and further decreased. Study of the stability and reversibility of the enzyme production revealed cell-to-cell heterogeneities in metabolic activities which could be linked to the reversibility of enzymatic activity changes. Thus, the strategy of successive transfers during the stationary phase of growth, combined with the use of complex lignocellulosic substrates as carbon sources, is an efficient strategy to optimize the hemicellulases production by T. xylanilyticus, by preventing the selection of cheaters.


Asunto(s)
Carbono , Xilanos , Bacterias/metabolismo , Carbono/metabolismo , Fibras de la Dieta/metabolismo , Endo-1,4-beta Xilanasas/metabolismo , Esterasas
10.
Microb Cell Fact ; 21(1): 39, 2022 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-35292016

RESUMEN

BACKGROUND: The microbial production of hemicellulasic cocktails is still a challenge for the biorefineries sector and agro-waste valorization. In this work, the production of hemicellulolytic enzymes by Thermobacillus xylanilyticus has been considered. This microorganism is of interest since it is able to produce an original set of thermostable hemicellulolytic enzymes, notably a xylanase GH11, Tx-xyn11. However, cell-to-cell heterogeneity impairs the production capability of the whole microbial population. RESULTS: Sequential cultivations of the strain on xylan as a carbon source has been considered in order to highlight and better understand this cell-to-cell heterogeneity. Successive cultivations pointed out a fast decrease of xylanase activity (loss of ~ 75%) and Tx-xyn11 gene expression after 23.5 generations. During serial cultivations on xylan, flow cytometry analyses pointed out that two subpopulations, differing at their light-scattering properties, were present. An increase of the recurrence of the subpopulation exhibiting low forward scatter (FSC) signal was correlated with a progressive loss of xylanase activity over several generations. Cell sorting and direct observation of the sorted subpopulations revealed that the low-FSC subpopulation was not sporulating, whereas the high-FSC subpopulation contained cells at the onset of the sporulation stage. The subpopulation differences (growth and xylanase activity) were assessed during independent growth. The low-FSC subpopulation exhibited a lag phase of 10 h of cultivation (and xylanase activities from 0.15 ± 0.21 to 3.89 ± 0.14 IU/mL along the cultivation) and the high-FSC subpopulation exhibited a lag phase of 5 h (and xylanase activities from 0.52 ± 0.00 to 4.43 ± 0.61 over subcultivations). Serial cultivations on glucose, followed by a switch to xylan led to a ~ 1.5-fold to ~ 15-fold improvement of xylanase activity, suggesting that alternating cultivation conditions could lead to an efficient population management strategy for the production of xylanase. CONCLUSIONS: Taken altogether, the data from this study point out that a cheating behavior is responsible for the progressive reduction in xylanase activity during serial cultivations of T. xylanilyticus. Alternating cultivation conditions between glucose and xylan could be used as an efficient strategy for promoting population stability and higher enzymatic productivity from this bacterium.


Asunto(s)
Bacillales , Endo-1,4-beta Xilanasas , Bacillales/metabolismo , Carbono/metabolismo , Endo-1,4-beta Xilanasas/genética , Endo-1,4-beta Xilanasas/metabolismo , Xilanos/metabolismo
11.
Curr Res Microb Sci ; 3: 100108, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35243445

RESUMEN

Lignocellulose, the most abundant biomass on Earth, is a complex recalcitrant material mainly composed of three fractions: cellulose, hemicelluloses and lignins. In nature, lignocellulose is efficiently degraded for carbon recycling. Lignocellulose degradation involves numerous microorganisms and their secreted enzymes that act in synergy. Even they are efficient, the natural processes for lignocellulose degradation are slow (weeks to months). In this study, the objective was to study the synergism of some microorganisms to achieve efficient and rapid lignocellulose degradation. Wheat bran, an abundant co-product from milling industry, was selected as lignocellulosic biomass. Mono-cultures and co-cultures involving one A.niger strain fungi never sequenced before (DSM 1957) and either one of three different Streptomyces strains were tested in order to investigate the potentiality for efficient lignocellulose degradability. Comparative genomics of the strain Aspergillus niger DSM 1957 revealed that it harboured the maximum of AA, CBM, CE and GH among its closest relative strains. The different co-cultures set-up enriched the metabolic diversity and the lignocellulolytic CAZyme content. Depending on the co-cultures, an over-expression of some enzymatic activities (xylanase, glucosidase, arabinosidase) was observed in the co-cultures compared to the mono-cultures suggesting a specific microbial cross-talk depending on the microbial partner. Moreover, metabolomics for each mono and co-culture was performed and revealed an elicitation of the production of secondary metabolites and the activation of silent biosynthetic cluster genes depending on the microbial co-culture. This opens opportunities for the bioproduction of molecules of interest from wheat bran.

12.
Microbiol Resour Announc ; 11(4): e0093421, 2022 Apr 21.
Artículo en Inglés | MEDLINE | ID: mdl-35258325

RESUMEN

Thermobacillus xylanilyticus is a thermophilic and hemicellulolytic bacterium able to use several lignocelluloses as its main carbon source. This draft genome sequence gives insight into the genomic potential of this bacterium and provides new resources to understand the enzymatic mechanisms used by the bacterium during lignocellulose degradation and will allow the identification of robust lignocellulolytic enzymes.

13.
Int J Syst Evol Microbiol ; 71(12)2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34889725

RESUMEN

A bacterial strain, named For3T, was isolated from forest soil sampled in Champenoux, France. Based on its 16S rRNA gene sequence, the strain was affiliated to the family Streptomycetaceae and, more specifically, to the genus Streptomyces. The strain had 99.93% 16S rRNA gene sequence similarity to its closest relative strains Streptomyces pratensis ATCC 33331T, Streptomyces anulatus ATCC 27416T, Streptomyces setonii NRRL ISP-5322T and Kitasatospora papulosa NRRL B-16504T. The phylogenomic tree using the genome blast distance phylogeny method showed that the closest relative strain was Streptomyces atroolivaceus NRRL ISP-5137T and that For3T represents a new branch among the Streptomyces. Genome relatedness indexes revealed that the average nucleotide identity and digital DNA-DNA hybridization values between For3T and its closest phylogenomic relative (S. atroolivaceus NRRL ISP-5137T) were 88.39 and 39.2 %, respectively. The G+C content of the genome was 71.4 mol% and its size was 7.96 Mb with 7492 protein-coding genes. Strain For3T harboured complete metabolic pathways absent in the closest relative strains such as cellulose biosynthesis, glycogen degradation I, glucosylglycerate biosynthesis I. Anteiso-C15:0, iso-C15:0, anteiso-C17:0 and MK-9(H4)/MK-9(H6) were the predominant cellular fatty acids and respiratory quinones, respectively. Phenotypic and genomic data supported the assignment of strain For3T to a novel species Streptomyces silvae sp. nov., within the genus Streptomyces, for which the type strain is For3T (=CIP 111908T=LMG 32186T).


Asunto(s)
Filogenia , Microbiología del Suelo , Streptomyces , Técnicas de Tipificación Bacteriana , Composición de Base , ADN Bacteriano/genética , Ácidos Grasos/química , Bosques , Francia , Hibridación de Ácido Nucleico , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Streptomyces/clasificación , Streptomyces/aislamiento & purificación , Vitamina K 2/análogos & derivados , Vitamina K 2/química
14.
J Agric Food Chem ; 69(44): 13217-13226, 2021 Nov 10.
Artículo en Inglés | MEDLINE | ID: mdl-34706532

RESUMEN

The enzymatic production of xylo-oligosaccharides (XOs) from destarched wheat bran with a GH11 xylanase was studied. Xylo-oligosaccharides (XOs) produced were separated into different fractions according to their degree of polymerization (DP) and the nature of their substituents: arabinoxylo-oligosaccharides (AXOs) with a DP from 2 to 3 and DP from 2 to 6 and feruloylated arabinoxylo-oligosaccharides (FAXOs) esterified by ferulic and p-coumaric acids with a DP from 3 to 6. Both AXOs (short and long DP) and FAXOs stimulated the growth of Bifidobacterium adolescentis, Faecalibacterium prausnitzii, and Prevotella copri similarly but not Lactobacillus rhamnosus. The utilization of AXOs and FAXOs as a carbon source resulted in the increase in turbidity, decrease in pH, and production of short-chain fatty acids (SCFAs) in the culture broth. The highest amount of SCFAs was produced by F. prausnitzii using FAXOs. Results suggest that FAXOs and AXOs have the potential to be considered as prebiotics.


Asunto(s)
Fibras de la Dieta , Probióticos , Bacterias/genética , Carbono , Oligosacáridos , Polimerizacion , Prebióticos , Prevotella , Xilanos
15.
J Biotechnol ; 339: 81-92, 2021 Sep 20.
Artículo en Inglés | MEDLINE | ID: mdl-34364925

RESUMEN

Pigments are compounds with highly diverse structures and wide uses, which production is increasing worldwide. An eco-friendly method of bioproduction is to use the ability of some microorganisms to ferment on renewable carbon sources. Wheat bran (WB) is a cheap and abundant lignocellulosic co-product of low recalcitrance to biological conversion. Microbial candidates with theoretical ability to degrade WB were first preselected using specific databases. The microorganisms were Ashbya gossypii (producing riboflavin), Chitinophaga pinensis (producing flexirubin), Chromobacterium vaccinii (violacein) and Gordonia alkanivorans (carotenoids). Growth was shown for each on minimal salt medium supplemented with WB at 5 g.L-1. Activities of the main enzymes consuming WB were measured, showing leucine amino-peptidase (up to 8.45 IU. mL-1) and ß-glucosidase activities (none to 6.44 IU. mL-1). This was coupled to a FTIR (Fourier Transform Infra-Red) study of the WB residues that showed main degradation of the WB protein fraction for C. pinensis, C. vaccinii and G. alkanivorans. Production of the pigments on WB was assessed for all the strains except Ashbya, with values of production reaching up to 1.47 mg.L-1. The polyphasic approach used in this study led to a proof of concept of pigment production from WB as a cheap carbon source.


Asunto(s)
Actinobacteria , Fibras de la Dieta , Bacteroidetes , Chromobacterium
16.
Microorganisms ; 9(7)2021 Jul 12.
Artículo en Inglés | MEDLINE | ID: mdl-34361919

RESUMEN

Mangrove sediments from New Caledonia were screened for xylanase sequences. One enzyme was selected and characterized both biochemically and for its industrial potential. Using a specific cDNA amplification method coupled with a MiSeq sequencing approach, the diversity of expressed genes encoding GH11 xylanases was investigated beneath Avicenia marina and Rhizophora stylosa trees during the wet and dry seasons and at two different sediment depths. GH11 xylanase diversity varied more according to tree species and season, than with respect to depth. One complete cDNA was selected (OFU29) and expressed in Pichia pastoris. The corresponding enzyme (called Xyn11-29) was biochemically characterized, revealing an optimal activity at 40-50 °C and at a pH of 5.5. Xyn11-29 was stable for 48 h at 35 °C, with a half-life of 1 h at 40 °C and in the pH range of 5.5-6. Xyn11-29 exhibited a high hydrolysis capacity on destarched wheat bran, with 40% and 16% of xylose and arabinose released after 24 h hydrolysis. Its activity on wheat straw was lower, with a release of 2.8% and 6.9% of xylose and arabinose, respectively. As the protein was isolated from mangrove sediments, the effect of sea salt on its activity was studied and discussed.

17.
Artículo en Inglés | MEDLINE | ID: mdl-34406922

RESUMEN

A bacterial strain, arapr2T, was isolated from agricultural soil sampled in Reims, France. Based on its 16S rRNA gene sequence, the strain was affiliated to the family Sphingobacteriaceae and more specifically to the genus Sphingobacterium. The strain had 98.31 % 16S rRNA gene sequence similarity to its closest relative Sphingobacterium canadense CR11T and 98.25 % to Sphingobacterium pakistanensis NCCP-246T. Genome relatedness indexes revealed that the average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between arapr2T and its closest relative (S. canadense CR11T) were 92.97 % and 52.00 %, respectively; for S. pakistanensis NCCP-246T, the ANI and dDDH values were 82.46 and 27.6%, respectively. The genomic DNA of strain arapr2T was 6.02 Mbp long, had a DNA G+C content of 40.4 mol% and had 5504 protein-coding genes. The results obtained in this study suggests that strain arapr2T (CIP 111872T=LMG 31848T) represents a new species for which the name Sphingobacterium prati sp. nov. is proposed. Due to the fact that this strain has been isolated using wheat straw as carbon source, this novel bacterial strain represents a promising biotechnological tool for the fractionation of lignocellulosic biomass in the context of biorefinery development.


Asunto(s)
Filogenia , Microbiología del Suelo , Sphingobacterium , Agricultura , Técnicas de Tipificación Bacteriana , Composición de Base , ADN Bacteriano/genética , Ácidos Grasos/química , Francia , Lignina , Hibridación de Ácido Nucleico , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Sphingobacterium/clasificación , Sphingobacterium/aislamiento & purificación
18.
Front Bioeng Biotechnol ; 9: 647442, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33898404

RESUMEN

Alkyl glycosides and sugars esters are non-ionic surfactants of interest for various applications (cosmetics, food, detergency,…). In the present study, xylans and cellulose from wheat bran were enzymatically converted into pentyl xylosides and glucose and xylose laurate monoesters. Transglycosylation reaction catalyzed by the commercial enzymatic cocktail Cellic Ctec2 in the presence of pentanol led to the synthesis of pentyl ß-D-xylosides from DP1 to 3 with an overall yield of 520 mg/g of xylans present in wheat bran. Enzymatic hydrolysis of wheat bran with Cellic Ctec2 and subsequent acylation of the recovered D-glucose and D-xylose catalyzed by the commercial lipase N435 in the presence of lauric acid or methyl laurate produced one D-glucose laurate monoester and one D-xylose laurate monoester. An integrated approach combining transglycosylation and (trans)esterification reactions was successfully developed to produce both pentyl xylosides and D-glucose and D-xylose laurate esters from the same batch of wheat bran.

20.
Microbiol Resour Announc ; 9(7)2020 Feb 13.
Artículo en Inglés | MEDLINE | ID: mdl-32054704

RESUMEN

The whole genome of Saccharibacillus sp. strain WB 17, a bacterial strain isolated from wheat phyllosphere, has been sequenced. This microorganism is equipped with several carbohydrate-active enzymes, which would explain its ability to fractionate lignocellulose.

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