Combined hemicellulolytic and phenoloxidase activities of Thermobacillus xylanilyticus enable growth on lignin-rich substrates and the release of phenolic molecules.

Major challenge in biorefineries is the use of all lignocellulosic components, particularly lignins. In this study, Thermobacillus xylanilyliticus grew on kraft lignin, steam-exploded and native wheat straws produced different sets of phenoloxidases and xylanases, according to the substrate. After growth, limited lignin structural modifications, mainly accompanied by a decrease in phenolic acids was observed by Nuclear Magnetic Resonance spectroscopy.

Paper-based electrodes as a tool for detecting ligninolytic enzymatic activities.

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.

A thermostable bacterial catalase-peroxidase oxidizes phenolic compounds derived from lignins.

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.

Control of phenotypic diversification based on serial cultivations on different carbon sources leads to improved bacterial xylanase production.

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.

Draft Genome Sequence of the Lignocellulolytic and Thermophilic Bacterium Thermobacillus xylanilyticus XE.

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.

Enzymatic Production of Xylo-oligosaccharides from Destarched Wheat Bran and the Impact of Their Degree of Polymerization and Substituents on Their Utilization as a Carbon Source by Probiotic Bacteria.

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 -coumaric acids with a DP from 3 to 6. Both AXOs (short and long DP) and FAXOs stimulated the growth of , , and similarly but not .

d-Xylose and l-arabinose laurate esters: Enzymatic synthesis, characterization and physico-chemical properties.

Efficient enzymatic synthesis of d-xylose and l-arabinose lauryl mono- and diesters has been achieved by transesterification reactions catalysed by immobilized Candida antarctica lipase B as biocatalyst, in organic medium in the presence of d-xylose or l-arabinose and vinyllaurate at 50 °C. In case of l-arabinose, one monoester and one diester were obtained in a 57% overall yield. A more complex mixture was produced for d-xylose as two monoesters and two diesters were synthesized in a 74.

The use of thermostable bacterial hemicellulases improves the conversion of lignocellulosic biomass to valuable molecules.

The hydrolysis of xylans, one of the main classes of carbohydrates that constitute lignocellulosic biomass, requires the synergistic action of several enzymes. The development of efficient enzymatic strategies for hydrolysis remains a challenge in the pursuit of viable biorefineries, particularly with respect to the valorisation of pentoses. The approach developed in this work is based on obtaining and characterising hemicellulasic cocktails from Thermobacillus xylanilyticus after culturing this bacterium on the hemicellulose-rich substrates wheat bran and wheat straw, which differ in their chemistries.

Engineering the hydrophobic residues of a GH11 xylanase impacts its adsorption onto lignin and its thermostability.

This study aimed to characterise the parameters governing the non-specific adsorption of a xylanase from Thermobacillus xylanilyticus (Tx-Xyn11) onto lignin isolated from maize stems. Such adsorption may be due to hydrophobic interactions between Tx-Xyn11 and lignin. Our strategy was to mutate hydrophobic residues present on the surface of Tx- Xyn11 into non-hydrophobic residues.

The hemicellulolytic enzyme arsenal of Thermobacillus xylanilyticus depends on the composition of biomass used for growth.

Background: Thermobacillus xylanilyticus is a thermophilic and highly xylanolytic bacterium. It produces robust and stable enzymes, including glycoside hydrolases and esterases, which are of special interest for the development of integrated biorefineries. To investigate the strategies used by T.

Aga1, the first alpha-Galactosidase from the human bacteria Ruminococcus gnavus E1, efficiently transcribed in gut conditions.

Differential gene expression analysis was performed in monoxenic mice colonized with Ruminococcus gnavus strain E1, a major endogenous member of the gut microbiota. RNA arbitrarily primed-PCR fingerprinting assays allowed to specifically detect the in vivo expression of the aga1 gene, which was further confirmed by RT-PCR. The aga1 gene encoded a protein of 744 residues with calculated molecular mass of 85,207 Da.

A thermostable feruloyl-esterase from the hemicellulolytic bacterium Thermobacillus xylanilyticus releases phenolic acids from non-pretreated plant cell walls.

A gene (Tx-est1) encoding a thermostable feruloyl-esterase was isolated from the genome of the gram-positive hemicellulolytic thermophilic bacterium Thermobacillus xylanilyticus. This gene contains an open reading frame of 1,020 bp encoding a protein with molecular mass of 37.4 kDa, similar to feruloyl-esterases from cellulolytic bacteria and fungi.

Proteomic identification of CBM37-containing cellulases produced by the rumen cellulolytic bacterium Ruminococcus albus 20 and their putative involvement in bacterial adhesion to cellulose.

The objective of this study was to identify and characterize other proteins than fimbrial proteins potentially involved in R. albus 20 adhesion to cellulose using an adhesion-related antiserum preparation (i.e.

The Ruminococcus albus pilA1-pilA2 locus: expression and putative role of two adjacent pil genes in pilus formation and bacterial adhesion to cellulose.

Ruminococcus albus produces fimbria-like structures that are involved with the bacterium's adhesion to cellulose. The subunit protein has been identified in strain 8 (CbpC) and strain 20 (GP25) and both are type IV fimbrial (Pil) proteins. The presence of a pil locus that is organized similarly in both strains is reported here together with the results of an initial examination of a second Pil protein.

Adhesion to cellulose of the Gram-positive bacterium Ruminococcus albus involves type IV pili.

This study was aimed at characterizing a cell-surface 25 kDa glycoprotein (GP25) that was previously shown to be underproduced by a spontaneous adhesion-defective mutant D5 of Ruminococcus albus 20. An antiserum against wild-type strain 20 was adsorbed with the mutant D5 to enrich it in antibodies 'specific' to adhesion structures of R. albus 20.