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The secretion of extracellular enzymes by soil microbes is rate-limiting in the recycling of biomass. Fungi and bacteria compete and collaborate for nutrients in the soil, with wide ranging ecological impacts. Within soil microbiota, the Bacteroidetes tend to be a dominant phylum, just like in human and animal intestines. The Bacteroidetes thrive because of their ability to secrete diverse arrays of carbohydrate-active enzymes (CAZymes) that target the highly varied glycans in the soil. Bacteroidetes use an energy-saving system of genomic organization, whereby most of their CAZymes are grouped into Polysaccharide Utilization Loci (PULs). These loci enable high level production of specific CAZymes only when their substrate glycans are abundant in the local environment. This gives the Bacteroidetes a clear advantage over other species in the competitive soil environment, further enhanced by the phylum-specific Type IX Secretion System (T9SS). The T9SS is highly effective at secreting CAZymes and/or tethering them to the cell surface, and is tightly coupled to the ability to rapidly glide over solid surfaces, a connection that promotes an active hunt for nutrition. Although the soil Bacteroidetes are less well studied than human gut symbionts, research is uncovering important biochemical and physiological phenomena. In this review, we summarize the state of the art on research into the CAZymes secreted by soil Bacteroidetes in the contexts of microbial soil ecology and the discovery of novel CAZymes for use in industrial biotechnology. We hope that this review will stimulate further investigations into the somewhat neglected enzymology of non-gut Bacteroidetes., QC 20210215

Members of the genera Proteiniphilum and Petrimonas were speculated to represent indicators reflecting process instability within anaerobic digestion (AD) microbiomes. Therefore, Petrimonas mucosa ING2-E5AT was isolated from a biogas reactor sample and sequenced on the PacBio RSII and Illumina MiSeq sequencers. Phylogenetic classification positioned the strain ING2-E5AT in close proximity to Fermentimonas and Proteiniphilum species (family Dysgonomonadaceae). ING2-E5AT encodes a number of genes for glycosyl-hydrolyses (GH) which are organized in Polysaccharide Utilization Loci (PUL) comprising tandem susCD-like genes for a TonB-dependent outer-membrane transporter and a cell surface glycan-binding protein. Different GHs encoded in PUL are involved in pectin degradation, reflecting a pronounced specialization of the ING2-E5AT PUL systems regarding the decomposition of this polysaccharide. Genes encoding enzymes participating in amino acids fermentation were also identified. Fragment recruitments with the ING2-E5AT genome as a template and publicly available metagenomes of AD microbiomes revealed that Petrimonas species are present in 146 out of 257 datasets supporting their importance in AD microbiomes. Metatranscriptome analyses of AD microbiomes uncovered active sugar and amino acid fermentation pathways for Petrimonas species. Likewise, screening of metaproteome datasets demonstrated expression of the Petrimonas PUL-specific component SusC providing further evidence that PUL play a central role for the lifestyle of Petrimonas species., Peer Reviewed

We examined the gene expression of the marine anaerobe Pontiella desulfatans F1(T) during growth on fucoidan from Fucus vesiculosus and on its monomer L-fucose with transcriptomics to obtain insight into the pathways involved. We observed upregulation of fucoidan-specific polysaccharide utilization loci (PULs), and found evidence for a novel L-fucose degradation pathway.

The genome and natural habitat of Chitinophaga pinensis suggest it has the ability to degrade a wide variety of carbohydrate-based biomass. Complementing our earlier investigations into the hydrolysis of some plant polysaccharides, we now show that C. pinensis can grow directly on spruce wood and on the fungal fruiting body. Growth was stronger on fungal material, although secreted enzyme activity was high in both cases, and all biomass-induced secretomes showed a predominance of beta-glucanase activities. We therefore conducted a screen for growth on and hydrolysis of beta-glucans isolated from different sources. Most noncrystalline beta-glucans supported good growth, with variable efficiencies of polysaccharide deconstruction and oligosaccharide uptake, depending on the polysaccharide backbone linkage. In all cases, beta-glucan was the only type of polysaccharide that was effectively hydrolyzed by secreted enzymes. This contrasts with the secretion of enzymes with a broad range of activities observed during growth on complex heteroglycans. Our findings imply a role for C. pinensis in the turnover of multiple types of biomass and suggest that the species may have two metabolic modes: a "scavenging mode," where multiple different types of glycan may be degraded, and a more "focused mode" of beta-glucan metabolism. The significant accumulation of some types of beta-gluco-oligosaccharides in growth media may be due to the lack of an appropriate transport mechanism, and we propose that this is due to the specificity of expressed polysaccharide utilization loci. We present a hypothetical model for beta-glucan metabolism by C. pinensis that suggests the potential for nutrient sharing among the microbial litter community. IMPORTANCE It is well known that the forest litter layer is inhabited by a complex microbial community of bacteria and fungi. However, while the importance of fungi in the turnover of natural biomass is well established, the role of their bacterial count, QC 20190130

Background: Acetylated 4-O-(methyl)glucuronoxylan (GX) is the main hemicellulose in deciduous hardwood, and comprises a β-(1→4)-linked xylopyranosyl (Xylp) backbone substituted by both acetyl groups and α-(1→2)-linked 4-O-methylglucopyranosyluronic acid (MeGlcpA). Whereas enzymes that target singly acetylated Xylp or doubly 2,3-O-acetyl-Xylp have been well characterized, those targeting (2-O-MeGlcpA)3-O-acetyl-Xylp structures in glucuronoxylan have remained elusive. Results: An unclassified carbohydrate esterase (FjoAcXE) was identified as a protein of unknown function from a polysaccharide utilization locus (PUL) otherwise comprising carbohydrate-active enzyme families known to target xylan. FjoAcXE was shown to efficiently release acetyl groups from internal (2-O-MeGlcpA)3-O-acetyl-Xylp structures, an activity that has been sought after but lacking in known carbohydrate esterases. FjoAcXE action boosted the activity of α-glucuronidases from families GH67 and GH115 by five and nine times, respectively. Moreover, FjoAcXE activity was not only restricted to GX, but also deacetylated (3-O-Araf)2-O-acetyl-Xylp of feruloylated xylooligomers, confirming the broad substrate range of this new carbohydrate esterase. Conclusion: This study reports the discovery and characterization of the novel carbohydrate esterase, FjoAcXE. In addition to cleaving singly acetylated Xylp, and doubly 2,3-O-acetyl-Xylp, FjoAcXE efficiently cleaves internal 3-O-acetyl-Xylp linkages in (2-O-MeGlcpA)3-O-acetyl-Xylp residues along with densely substituted and branched xylooligomers; activities that until now were missing from the arsenal of enzymes required for xylan conversion.

The human gastrointestinal tract harbours myriad bacterial species, collectively termed the microbiota, that strongly influence human health. Symbiotic members of our microbiota play a pivotal role in the digestion of complex carbohydrates that are otherwise recalcitrant to assimilation. Indeed, the intrinsic human polysaccharide-degrading enzyme repertoire is limited to various starch-based substrates; more complex polysaccharides demand microbial degradation. Select Bacteroidetes are responsible for the degradation of the ubiquitous vegetable xyloglucans (XyGs), through the concerted action of cohorts of enzymes and glycan-binding proteins encoded by specific xyloglucan utilization loci (XyGULs). Extending recent (meta) genomic, transcriptomic and biochemical analyses, significant questions remain regarding the structural biology of the molecular machinery required for XyG saccharification. Here, we reveal the three-dimensional structures of an alpha-xylosidase, a beta-glucosidase, and two alpha-L-arabinofuranosidases from the Bacteroides ovatus XyGUL. Aided by bespoke ligand synthesis, our analyses highlight key adaptations in these enzymes that confer individual specificity for xyloglucan side chains and dictate concerted, stepwise disassembly of xyloglucan oligosaccharides. In harness with our recent structural characterization of the vanguard endo-xyloglucanse and cell-surface glycan-binding proteins, the present analysis provides a near-complete structural view of xyloglucan recognition and catalysis by XyGUL proteins., QC 20161012

Flavobacterium suncheonense is a member of the family Flavobacteriaceae in the phylum Bacteroidetes. Strain GH29-5(T) (DSM 17707(T)) was isolated from greenhouse soil in Suncheon, South Korea. F. suncheonense GH29-5(T) is part of the G enomic E ncyclopedia of B acteria and A rchaea project. The 2,880,663 bp long draft genome consists of 54 scaffolds with 2739 protein-coding genes and 82 RNA genes. The genome of strain GH29-5(T) has 117 genes encoding peptidases but a small number of genes encoding carbohydrate active enzymes (51 CAZymes). Metallo and serine peptidases were found most frequently. Among CAZymes, eight glycoside hydrolase families, nine glycosyl transferase families, two carbohydrate binding module families and four carbohydrate esterase families were identified. Suprisingly, polysaccharides utilization loci (PULs) were not found in strain GH29-5(T). Based on the coherent physiological and genomic characteristics we suggest that F. suncheonense GH29-5(T) feeds rather on proteins than saccharides and lipids.

Flavobacterium suncheonense is a member of the family Flavobacteriaceae in the phylum Bacteroidetes. Strain GH29-5(T) (DSM 17707(T)) was isolated from greenhouse soil in Suncheon, South Korea. F. suncheonense GH29-5(T) is part of the G enomic E ncyclopedia of B acteria and A rchaea project. The 2,880,663 bp long draft genome consists of 54 scaffolds with 2739 protein-coding genes and 82 RNA genes. The genome of strain GH29-5(T) has 117 genes encoding peptidases but a small number of genes encoding carbohydrate active enzymes (51 CAZymes). Metallo and serine peptidases were found most frequently. Among CAZymes, eight glycoside hydrolase families, nine glycosyl transferase families, two carbohydrate binding module families and four carbohydrate esterase families were identified. Suprisingly, polysaccharides utilization loci (PULs) were not found in strain GH29-5(T). Based on the coherent physiological and genomic characteristics we suggest that F. suncheonense GH29-5(T) feeds rather on proteins than saccharides and lipids.

Flavobacterium rivuli Ali et al. 2009 emend. Dong et al. 2013 is one of about 100 species in the genus Flavobacterium (family Flavobacteriacae, phylum Bacteroidetes) with a validly published name, and has been isolated from the spring of a hard water rivulet in Northern Germany. Including all type strains of the genus Myroides and Flavobacterium into the 16S rRNA gene sequence phylogeny revealed a clustering of members of the genus Myroides as a monophyletic group within the genus Flavobacterium. Furthermore, F. rivuli WB 3.3-2(T) and its next relatives seem more closely related to the genus Myroides than to the type species of the genus Flavobacterium, F. aquatile. The 4,489,248 bp long genome with its 3,391 protein-coding and 65 RNA genes is part of the G enomic E ncyclopedia of B acteria and A rchaea project. The genome of F. rivuli has almost as many genes encoding carbohydrate active enzymes (151 CAZymes) as genes encoding peptidases (177). Peptidases comprised mostly metallo (M) and serine (S) peptidases. Among CAZymes, 30 glycoside hydrolase families, 10 glycosyl transferase families, 7 carbohydrate binding module families and 7 carbohydrate esterase families were identified. Furthermore, we found four polysaccharide utilization loci (PUL) and one large CAZy rich gene cluster that might enable strain WB 3.3-2(T) to decompose plant and algae derived polysaccharides. Based on these results we propose F. rivuli as an interesting candidate for further physiological studies and the role of Bacteroidetes in the decomposition of complex polymers in the environment.

Homogalacturonan (HG) is a structural plant cell wall polysaccharide and a key source of dietary fiber. The human genome does not contain a single enzyme known to be involved in pectin digestion, and therefore, in order to modify HG fibers and potentially extract nutritional value, humans rely on a consortium of symbiotic intestinal bacteria, such as Bacteroides thetaiotaomicron, to deconstruct and to ferment this complex carbohydrate into host absorbable products. B. thetaiotaomicron contains over 300 predicted carbohydrate active enzymes within its genome that are primarily organized into sugar-selective metabolic pathways called Polysaccharide Utilization Loci PULs (PULs). One such PUL (PUL75: BT4108-BT4124), is activated by HG and is believed to contain enzymes that convert polymerized HG into monosaccharides (GalA). This study reports molecular biology, biochemistry, and functional genomics data that characterize the function of PUL75 gene products involved in HG utilization. Based on these findings, a model for the step-wise process of HG recognition, transport and modification by PUL75 is proposed.

Homogalacturonan (HG) is a structural plant cell wall polysaccharide and a key source of dietary fiber. The human genome does not contain a single enzyme known to be involved in pectin digestion, and therefore, in order to modify HG fibers and potentially extract nutritional value, humans rely on a consortium of symbiotic intestinal bacteria, such as Bacteroides thetaiotaomicron, to deconstruct and to ferment this complex carbohydrate into host absorbable products. B. thetaiotaomicron contains over 300 predicted carbohydrate active enzymes within its genome that are primarily organized into sugar-selective metabolic pathways called Polysaccharide Utilization Loci PULs (PULs). One such PUL (PUL75: BT4108-BT4124), is activated by HG and is believed to contain enzymes that convert polymerized HG into monosaccharides (GalA). This study reports molecular biology, biochemistry, and functional genomics data that characterize the function of PUL75 gene products involved in HG utilization. Based on these findings, a model for the step-wise process of HG recognition, transport and modification by PUL75 is proposed.

Homogalacturonan (HG) is a structural plant cell wall polysaccharide and a key source of dietary fiber. The human genome does not contain a single enzyme known to be involved in pectin digestion, and therefore, in order to modify HG fibers and potentially extract nutritional value, humans rely on a consortium of symbiotic intestinal bacteria, such as Bacteroides thetaiotaomicron, to deconstruct and to ferment this complex carbohydrate into host absorbable products. B. thetaiotaomicron contains over 300 predicted carbohydrate active enzymes within its genome that are primarily organized into sugar-selective metabolic pathways called Polysaccharide Utilization Loci PULs (PULs). One such PUL (PUL75: BT4108-BT4124), is activated by HG and is believed to contain enzymes that convert polymerized HG into monosaccharides (GalA). This study reports molecular biology, biochemistry, and functional genomics data that characterize the function of PUL75 gene products involved in HG utilization. Based on these findings, a model for the step-wise process of HG recognition, transport and modification by PUL75 is proposed.

Homogalacturonan (HG) is a structural plant cell wall polysaccharide and a key source of dietary fiber. The human genome does not contain a single enzyme known to be involved in pectin digestion, and therefore, in order to modify HG fibers and potentially extract nutritional value, humans rely on a consortium of symbiotic intestinal bacteria, such as Bacteroides thetaiotaomicron, to deconstruct and to ferment this complex carbohydrate into host absorbable products. B. thetaiotaomicron contains over 300 predicted carbohydrate active enzymes within its genome that are primarily organized into sugar-selective metabolic pathways called Polysaccharide Utilization Loci PULs (PULs). One such PUL (PUL75: BT4108-BT4124), is activated by HG and is believed to contain enzymes that convert polymerized HG into monosaccharides (GalA). This study reports molecular biology, biochemistry, and functional genomics data that characterize the function of PUL75 gene products involved in HG utilization. Based on these findings, a model for the step-wise process of HG recognition, transport and modification by PUL75 is proposed.

Homogalacturonan (HG) is a structural plant cell wall polysaccharide and a key source of dietary fiber. The human genome does not contain a single enzyme known to be involved in pectin digestion, and therefore, in order to modify HG fibers and potentially extract nutritional value, humans rely on a consortium of symbiotic intestinal bacteria, such as Bacteroides thetaiotaomicron, to deconstruct and to ferment this complex carbohydrate into host absorbable products. B. thetaiotaomicron contains over 300 predicted carbohydrate active enzymes within its genome that are primarily organized into sugar-selective metabolic pathways called Polysaccharide Utilization Loci PULs (PULs). One such PUL (PUL75: BT4108-BT4124), is activated by HG and is believed to contain enzymes that convert polymerized HG into monosaccharides (GalA). This study reports molecular biology, biochemistry, and functional genomics data that characterize the function of PUL75 gene products involved in HG utilization. Based on these findings, a model for the step-wise process of HG recognition, transport and modification by PUL75 is proposed.

Homogalacturonan (HG) is a structural plant cell wall polysaccharide and a key source of dietary fiber. The human genome does not contain a single enzyme known to be involved in pectin digestion, and therefore, in order to modify HG fibers and potentially extract nutritional value, humans rely on a consortium of symbiotic intestinal bacteria, such as Bacteroides thetaiotaomicron, to deconstruct and to ferment this complex carbohydrate into host absorbable products. B. thetaiotaomicron contains over 300 predicted carbohydrate active enzymes within its genome that are primarily organized into sugar-selective metabolic pathways called Polysaccharide Utilization Loci PULs (PULs). One such PUL (PUL75: BT4108-BT4124), is activated by HG and is believed to contain enzymes that convert polymerized HG into monosaccharides (GalA). This study reports molecular biology, biochemistry, and functional genomics data that characterize the function of PUL75 gene products involved in HG utilization. Based on these findings, a model for the step-wise process of HG recognition, transport and modification by PUL75 is proposed.

Homogalacturonan (HG) is a structural plant cell wall polysaccharide and a key source of dietary fiber. The human genome does not contain a single enzyme known to be involved in pectin digestion, and therefore, in order to modify HG fibers and potentially extract nutritional value, humans rely on a consortium of symbiotic intestinal bacteria, such as Bacteroides thetaiotaomicron, to deconstruct and to ferment this complex carbohydrate into host absorbable products. B. thetaiotaomicron contains over 300 predicted carbohydrate active enzymes within its genome that are primarily organized into sugar-selective metabolic pathways called Polysaccharide Utilization Loci PULs (PULs). One such PUL (PUL75: BT4108-BT4124), is activated by HG and is believed to contain enzymes that convert polymerized HG into monosaccharides (GalA). This study reports molecular biology, biochemistry, and functional genomics data that characterize the function of PUL75 gene products involved in HG utilization. Based on these findings, a model for the step-wise process of HG recognition, transport and modification by PUL75 is proposed.

Homogalacturonan (HG) is a structural plant cell wall polysaccharide and a key source of dietary fiber. The human genome does not contain a single enzyme known to be involved in pectin digestion, and therefore, in order to modify HG fibers and potentially extract nutritional value, humans rely on a consortium of symbiotic intestinal bacteria, such as Bacteroides thetaiotaomicron, to deconstruct and to ferment this complex carbohydrate into host absorbable products. B. thetaiotaomicron contains over 300 predicted carbohydrate active enzymes within its genome that are primarily organized into sugar-selective metabolic pathways called Polysaccharide Utilization Loci PULs (PULs). One such PUL (PUL75: BT4108-BT4124), is activated by HG and is believed to contain enzymes that convert polymerized HG into monosaccharides (GalA). This study reports molecular biology, biochemistry, and functional genomics data that characterize the function of PUL75 gene products involved in HG utilization. Based on these findings, a model for the step-wise process of HG recognition, transport and modification by PUL75 is proposed.

Homogalacturonan (HG) is a structural plant cell wall polysaccharide and a key source of dietary fiber. The human genome does not contain a single enzyme known to be involved in pectin digestion, and therefore, in order to modify HG fibers and potentially extract nutritional value, humans rely on a consortium of symbiotic intestinal bacteria, such as Bacteroides thetaiotaomicron, to deconstruct and to ferment this complex carbohydrate into host absorbable products. B. thetaiotaomicron contains over 300 predicted carbohydrate active enzymes within its genome that are primarily organized into sugar-selective metabolic pathways called Polysaccharide Utilization Loci PULs (PULs). One such PUL (PUL75: BT4108-BT4124), is activated by HG and is believed to contain enzymes that convert polymerized HG into monosaccharides (GalA). This study reports molecular biology, biochemistry, and functional genomics data that characterize the function of PUL75 gene products involved in HG utilization. Based on these findings, a model for the step-wise process of HG recognition, transport and modification by PUL75 is proposed.

Homogalacturonan (HG) is a structural plant cell wall polysaccharide and a key source of dietary fiber. The human genome does not contain a single enzyme known to be involved in pectin digestion, and therefore, in order to modify HG fibers and potentially extract nutritional value, humans rely on a consortium of symbiotic intestinal bacteria, such as Bacteroides thetaiotaomicron, to deconstruct and to ferment this complex carbohydrate into host absorbable products. B. thetaiotaomicron contains over 300 predicted carbohydrate active enzymes within its genome that are primarily organized into sugar-selective metabolic pathways called Polysaccharide Utilization Loci PULs (PULs). One such PUL (PUL75: BT4108-BT4124), is activated by HG and is believed to contain enzymes that convert polymerized HG into monosaccharides (GalA). This study reports molecular biology, biochemistry, and functional genomics data that characterize the function of PUL75 gene products involved in HG utilization. Based on these findings, a model for the step-wise process of HG recognition, transport and modification by PUL75 is proposed.