Linear Plasmids in Micrococcus: Insights Into a Common Ancestor and Transfer by Conjugation.

Actinobacteria have frequently been reported in the Andean Puna, including strains of the genus Micrococcus. These strains demonstrate resistance to high levels of UV radiation, arsenic, and multiple antibiotics, and possess large linear plasmids. A comparative analysis of the sequences and putative functions of these plasmids was conducted.

Markerless deletion of the putative type I and III restriction-modification systems in the cellulolytic bacterium Clostridium cellulovorans using a codBA-based counterselection technique.

Cellulose from lignocellulosic biomass (LB) is of increasing interest for the production of commodity chemicals. However, its use as substrate for fermentations is a challenge due to its structural complexity. In this context, the highly cellulolytic Clostridium cellulovorans has been considered an interesting microorganism for the breakdown of LB.

Carbohydrate Metabolism Differentiates and Species Growing in Beer.

Obligate anaerobic beer spoilage bacteria have been a menace to the brewing industry for several decades. Technological advances in the brewing process aimed at suppressing aerobic spoilers gave rise to problems with obligate anaerobes. In previous studies, the metabolic spectrum of and species has been described, but their metabolism in the beer environment remains largely unknown.

Identification of a novel xanthan-binding module of a multi-modular sp. xanthanase.

A new strain of xanthan-degrading bacteria identified as sp. has been isolated from a xanthan thickener for food production. The strain was able to utilize xanthan as the only carbon source and to reduce the viscosity of xanthan-containing medium during cultivation.

Proteomic analysis of Viscozyme L and its major enzyme components for pectic substrate degradation.

Enzymatic degradation of plant biomass requires the coordinated action of various enzymes. In this study, the production of reducing sugars from pectic substrates and sugar beet pulp (SBP) was investigated and compared using commercial enzyme preparations, including M2, pectinase (E1), Viscozyme L (V-L) and L-40. V-L, a cellulolytic enzyme mix produced by Aspergillus sp.

Xanthan: enzymatic degradation and novel perspectives of applications.

The extracellular heteropolysaccharide xanthan, synthesized by bacteria of the genus Xanthomonas, is widely used as a thickening and stabilizing agent across the food, cosmetic, and pharmaceutical sectors. Expanding the scope of its application, current efforts target the use of xanthan to develop innovative functional materials and products, such as edible films, eco-friendly oil surfactants, and biocompatible composites for tissue engineering. Xanthan-derived oligosaccharides are useful as nutritional supplements and plant defense elicitors.

Continuous Production of Ethanol, 1-Butanol and 1-Hexanol from CO with a Synthetic Co-Culture of Applying a Cascade of Stirred-Tank Bioreactors.

Syngas fermentation with clostridial co-cultures is promising for the conversion of CO to alcohols. A CO sensitivity study with monocultures in batch operated stirred-tank bioreactors revealed total growth inhibition of already at 100 mbar CO, but stable biomass concentrations and ongoing chain elongation at 800 mbar CO. On/off-gassing with CO indicated a reversible inhibition of .

Analysis of cellulose synthesis in a high-producing acetic acid bacterium Komagataeibacter hansenii.

Bacterial cellulose (BC) represents a renewable biomaterial with unique properties promising for biotechnology and biomedicine. Komagataeibacter hansenii ATCC 53,582 is a well-characterized high-yield producer of BC used in the industry. Its genome encodes three distinct cellulose synthases (CS), bcsAB1, bcsAB2, and bcsAB3, which together with genes for accessory proteins are organized in operons of different complexity.

gen. nov., sp. nov., a mesophilic proteolytic salt-tolerant bacterium isolated from a laboratory-scale biogas fermenter, and emended description of .

An anaerobic bacterial strain, designated strain M3/9, was isolated from a laboratory-scale biogas fermenter fed with maize silage supplemented with 5 % wheat straw. Cells were straight, non-motile rods, which stained Gram-negative. Optimal growth occurred between 30 and 40°C, at pH 7.

Combining omics tools for the characterization of the microbiota of diverse vinegars obtained by submerged culture: 16S rRNA amplicon sequencing and MALDI-TOF MS.

Vinegars elaborated in southern Spain are highly valued all over the world because of their exceptional organoleptic properties and high quality. Among the factors which influence the characteristics of the final industrial products, the composition of the microbiota responsible for the process and the raw material used as acetification substrate have a crucial role. The current state of knowledge shows that few microbial groups are usually present throughout acetification, mainly acetic acid bacteria (AAB), although other microorganisms, present in smaller proportions, may also affect the overall activity and behavior of the microbial community.

Arabinan saccharification by biogas reactor metagenome-derived arabinosyl hydrolases.

Background: Plant cell walls represent the most plentiful renewable organic resource on earth, but due to their heterogeneity, complex structure and partial recalcitrance, their use as biotechnological feedstock is still limited.

Results: In order to identify efficient enzymes for polysaccharide breakdown, we have carried out functional screening of metagenomic fosmid libraries from biogas fermenter microbial communities grown on sugar beet pulp, an arabinan-rich agricultural residue, or other sources containing microbes that efficiently depolymerize polysaccharides, using CPH (chromogenic polysaccharide hydrogel) or ICB (insoluble chromogenic biomass) labeled polysaccharide substrates. Seventy-one depolymerase-encoding genes were identified from 55 active fosmid clones by using Illumina and Sanger sequencing and dbCAN CAZyme (carbohydrate-active enzyme) annotation.

RNA-Seq transcriptomic analysis reveals gene expression profiles of acetic acid bacteria under high-acidity submerged industrial fermentation process.

Acetic acid bacteria (AAB) are Gram-negative obligate aerobics in Acetobacteraceae family. Producing acetic acid and brewing vinegars are one of the most important industrial applications of AAB, attributed to their outstanding ability to tolerate the corresponding stresses. Several unique acid resistance (AR) mechanisms in AAB have been revealed previously.

Biochemical and Structural Characterization of Thermostable GH159 Glycoside Hydrolases Exhibiting α-L-Arabinofuranosidase Activity.

Functional, biochemical, and preliminary structural properties are reported for three glycoside hydrolases of the recently described glycoside hydrolase (GH) family 159. The genes were cloned from the genomic sequences of different strains. This study extends the spectrum of functions of GH159 enzymes.

Oxidative Fermentation of Acetic Acid Bacteria and Its Products.

Acetic acid bacteria (AAB) are a group of Gram-negative, strictly aerobic bacteria, including 19 reported genera until 2021, which are widely found on the surface of flowers and fruits, or in traditionally fermented products. Many AAB strains have the great abilities to incompletely oxidize a large variety of carbohydrates, alcohols and related compounds to the corresponding products mainly including acetic acid, gluconic acid, gulonic acid, galactonic acid, sorbose, dihydroxyacetone and miglitol the membrane-binding dehydrogenases, which is termed as AAB oxidative fermentation (AOF). Up to now, at least 86 AOF products have been reported in the literatures, but no any monograph or review of them has been published.

The Roles of the Various Cellulose Biosynthesis Operons in ATCC 23769.

Cellulose is the most abundant biopolymer on earth and offers versatile applicability in biotechnology. Bacterial cellulose, especially, is an attractive material because it represents pure microcrystalline cellulose. The cellulose synthase complex of acetic acid bacteria serves as a model for general studies on (bacterial) cellulose synthesis.

Unusual substrate specificity in GH family 12: structure-function analysis of glucanases Bgh12A and Xgh12B from Aspergillus cervinus, and Egh12 from Thielavia terrestris.

In this study, we compared the properties and structures of three fungal GH12 enzymes: the strict endoglucanase Bgh12A and the xyloglucanase Xgh12B from Aspergillus cervinus, and the endoglucanase Egh12 from Thielavia terrestris combining activity on linear β-glucan and branched xyloglucan. Egh12 from T. terrestris was produced in Pichia pastoris, purified, and characterized as a thermostable enzyme with maximal activity at 70 ºC and a half-life time of 138 min at 65 °C.

Molecular biology: Fantastic toolkits to improve knowledge and application of acetic acid bacteria.

Acetic acid bacteria (AAB) are a group of gram-negative, obligate aerobic bacteria within the Acetobacteraceae family of the alphaproteobacteria class, which are distributed in a wide variety of different natural sources that are rich in sugar and alcohols, as well as in several traditionally fermented foods. Their versatile capabilities are not limited to producing acetic acid and brewing vinegar, as their names suggest. They can also be used for fixing nitrogen, yielding pigments and exopolysaccharides (EPS), and most typically, producing a variety of aldehydes, ketones and other organic acids from the incomplete oxidation of the corresponding alcohols and/or sugars (also referred to as oxidative fermentation).

Monitoring co-cultures of Clostridium carboxidivorans and Clostridium kluyveri by fluorescence in situ hybridization with specific 23S rRNA oligonucleotide probes.

The development of co-cultures of clostridial strains which combine different physiological traits represents a promising strategy to achieve the environmentally friendly production of biofuels and chemicals. For the optimization of such co-cultures it is essential to monitor their composition and stability throughout fermentation. FISH is a quick and sensitive method for the specific labeling and quantification of cells within microbial communities.

gen. nov., sp. nov., a new member of the family , isolated from a maize-fed biogas fermenter.

Strain MD1 is an anaerobic, Gram-stain-negative bacterium isolated from a lab-scale biogas fermenter fed with maize silage. It has a rod-shaped morphology with peritrichously arranged appendages and forms long chains of cells and coccoid structures. The colonies of MD1 were white, circular, slightly convex and had a smooth rim.

Synthetic co-culture of autotrophic Clostridium carboxidivorans and chain elongating Clostridium kluyveri monitored by flow cytometry.

Syngas fermentation with acetogens is known to produce mainly acetate and ethanol efficiently. Co-cultures with chain elongating bacteria making use of these products are a promising approach to produce longer-chain alcohols. Synthetic co-cultures with identical initial cell concentrations of Clostridium carboxidivorans and Clostridium kluyveri were studied in batch-operated stirred-tank bioreactors with continuous CO/CO -gassing and monitoring of the cell counts of both clostridia by flow cytometry after fluorescence in situ hybridization (FISH-FC).

Towards valorization of pectin-rich agro-industrial residues: Engineering of Saccharomyces cerevisiae for co-fermentation of d-galacturonic acid and glycerol.

Pectin-rich plant biomass residues represent underutilized feedstocks for industrial biotechnology. The conversion of the oxidized monomer d-galacturonic acid (d-GalUA) to highly reduced fermentation products such as alcohols is impossible due to the lack of electrons. The reduced compound glycerol has therefore been considered an optimal co-substrate, and a cell factory able to efficiently co-ferment these two carbon sources is in demand.

Identification of New Chromosomal Loci Involved in Genes Expression and Natural Transformation in the Actinobacterial Model Organism .

Historically, was one of the first organisms used to study natural transformation, one of the main routes of horizontal gene transfer among prokaryotes. However, little is known about the molecular basis of competence development in or any other representative of the phylum of high-GC Gram-positive bacteria (Actinobacteria), while this means of genetic exchange has been studied in great detail in Gram-negative and low-GC Gram-positive bacteria (Firmicutes). In order to identify new genetic elements involved in regulation of the - competence operon in , we conducted random chemical mutagenesis of a reporter strain expressing under the control of the - promoter, followed by the screening of dysregulated mutants.

Characterization of Two α-l-Arabinofuranosidases from and Their Synergistic Effect in Degradation of Arabinose-Containing Substrates.

Arabinofuranosidases are important accessory enzymes involved in the degradation of arabinose-containing poly- and oligosaccharides. Two arabinofuranosidases from the recently described novel anaerobic cellulolytic bacterium , designated Araf51 and Araf43, were heterologously expressed in and biochemically characterized. Araf51 not only removed arabinose moieties at O-3, O-2 and terminal O-5 positions of arabinose-containing oligosaccharides, but also exhibited exo-β-xylosidase side activity.

Draft Genome Sequence of Clostridium beijerinckii Strain mbf-VZ-132, Isolated from an Environmental Soil Sample.

strain mbf-VZ-132 was isolated from soil in Freising-Weihenstephan (Bavaria, Germany). The 16S rRNA gene sequence showed a 99.9% sequence identity to that of DSM 15410, which was recently reclassified as In this study, we present the draft genome sequence of mbf-VZ-132 based on PacBio sequencing.