Carbohydrate Degradation Research Articles

Demonstration of adapted packed-bed bioreactor for accurate and rapid estimation of biochemical oxygen demand: insights into the influence of microbial community structure and functions.

This study demonstrated a novel approach to accurately estimate 5-day biochemical oxygen demand (BOD5) in textile wastewater using a microbial consortium from food processing wastewater fixed on coconut fibers. Although glucose-glutamic acid (GGA) has been widely known as the most preferred substrates for microbial respiration, its calibration surprisingly resulted in an overestimation of BOD5 in textile wastewater due to its lower utilization rate compared to that of textile wastewater. After being adapted with a new nutrient environment composed of GGA and textile wastewater, the adapted packed-bed bioreactors (PBBRs) was capable of accurate estimation of BOD5 in textile wastewater using GGA standard solution. Metagenomic analysis revealed the dominance of the genera Enterobacter, Acinetobacter, Chryseobacterium, and Comamonas in the adapted microbial community, which are recognized for their significant potential in azo dye degradation. The imputed metagenome showed an enhanced showed an enhanced abundance of "Amino Acid Degradation" and "Carbohydrate Degradation" functions, confirming the improved ability of adapted community to utilization of GGA in the standard solution. These findings suggest that adaptation of exogenous microbial consortium to a nutrient environment composed of GGA and target wastewater may shift the community to that dominated by strains having both utilization ability of GGA and target compounds which, in turn, enhance the accuracy of the adapted PBBRs for estimation of BOD5 in target wastewater.

Diversity and physiology of abundant Rhodoferax species in global wastewater treatment systems.

Wastewater treatment plants rely on complex microbial communities for bioconversion and removal of pollutants, but many process-critical species are still poorly investigated. One of these genera is Rhodoferax, an abundant core genus in wastewater treatment plants across the world. The genus has been associated with many metabolic traits such as iron reduction and oxidation and denitrification. We used 16S rRNA gene amplicon data to uncover the diversity and abundance of Rhodoferax species in Danish and global treatment plants. Publicly available metagenome-assembled genomes were analyzed based on phylogenomics to delineate species and assign taxonomies based on the SeqCode. The phylogenetic analysis of "Rhodoferax" revealed that species previously assigned to Rhodoferax in wastewater treatment plants should be considered as at least eight different genera, with five representing previously undescribed genera. Genome annotation showed potential for several key-bioconversions in wastewater treatment, such as nitrate reduction, carbohydrate degradation, and accumulations of various storage compounds. Iron oxidation and reduction capabilities were not predicted for abundant species. Species-resolved FISH-Raman was performed to gain an overview of the morphology and ecophysiology of selected taxa to clarify their potential role in global wastewater treatment systems. Our study provides a first insight into the functional and ecological characteristics of several novel genera abundant in global wastewater treatment plants, previously assigned to the Rhodoferax genus.

New C-linked diarylheptanoid dimers as potential α-glucosidase inhibitors evidenced by biological, spectral and theoretical approaches.

Diabetes mellitus (DM) is a chronic metabolic disorder characterized by elevated blood glucose levels, generally due to defects of insulin action or secretion. Inhibition of α-glucosidase, an enzyme responsible for carbohydrate degradation, is a promising strategy for managing postprandial hyperglycemia in diabetic patients. In this study, two new C-linked diarylheptanoid dimers, kaemgalanganols A (1) and B (2), were isolated from K. galanga, which showed obvious inhibitory activity on α-glucosidase but weak activity on protein tyrosine phosphatase 1B (PTP1B). Kaemgalanganol B had an IC50 value of 35.1μM against α-glucosidase, obviously more potent than kaemgalanganol A (IC50=78.5μM) and acarbose (IC50=363.0μM). Enzyme kinetic study indicated that 2 was a reversible mixed-type inhibitor of α-glucosidase via non-competitive and anti-competitive inhibition modes. Fluorescence quenching and UV-visible spectroscopic study revealed that fluorescence quenching mechanism of 2 on α-glucosidase is a combination of dynamic quenching and static quenching, accompanied by non-radiative energy transfer. Compound 2 formed complex with α-glucosidase closer to the Tyr residue, and induced changes in both the microenvironment and peptide backbone. Surface hydrophobicity and CD spectra measurement indicated that 2 affected the function of α-glucosidase by decreasing the surface hydrophobicity of α-glucosidase as well as altering the secondary structure instead of the overall three-dimensional framework, which is consistent with the results of fluorescence experiment. Molecular docking manifested that compound 2 had a strong binding affinity (-7.27kcal/mol) with α-glucosidase, higher than 1 (-9.82kcal/mol) and acarbose (-4.48kcal/mol), consistent with the enzyme inhibitory assay. Besides hydrogen bonds, electrostatic interactions and hydrophobic interactions played important roles in the binding of 2 with α-glucosidase. This study disclosed the inhibitory activity and mechanism of 2 against α-glucosidase, which provides a theoretical basis for the development of new antidiabetic drugs form K. galanga.

Efficient Control of Fusarium Head Blight and Reduction of Deoxynivalenol Accumulation by a Novel Nanopartner-Based Strategy.

Chemical control of Fusarium head blight (FHB) in wheat plants is often challenged by the resistance outbreak and deoxynivalenol (DON) accumulation. Developing green partners for fungicides is crucial for reducing fungal growth, mycotoxin contamination, and agricultural fungicides input. Herein, we investigated the mechanism of MgO nanoparticles (NPs) in controlling FHB. The EC50 of MgO NPs on mycelial growth was 105.2 μg/mL. At this concentration, they inhibited the spore germination, DON production, and wheat colonization of Fusarium graminearum by 56.0%, 24.5%, and 43.8%, respectively, exhibiting superior performance compared to nine other bioactive NPs such as ZnO and TiO2. Importantly, MgO NPs showed an additive effect with carbendazim and azoxystrobin in inhibiting F. graminearum. The extracellular toxicity of MgO NPs against F. graminearum was mainly attributed to the inhibition of fungal growth and germination by oxidative damage, alkaline damage, and cell structure damage. Although MgO NPs could not be absorbed into mycelia, they (EC90) decreased the soluble protein content and DNA concentration of mycelia by 27.8% and 42.3%, respectively, and increased the pyruvate content by 67.4%, demonstrating that the intracellular toxicity was mainly based on their inhibition of protein and DNA production and promotion of carbohydrate degradation. With low risks to nontarget organisms, MgO NPs could be a promising nanopartner for fungicides to protect wheat from FHB and mitigate fungicide overuse.

Insights into the Donkey Hindgut Microbiome Using Metagenome-Assembled Genomes.

The gut microbiota plays an important role in the digestion, absorption, and metabolism of nutrients, as well as in the immunity, health, and behavior of donkeys. While reference genomes and gut microbial gene catalogs have been helpful in understanding the composition of the donkey, there is still a significant gap in sequencing and understanding the functional aspects of donkey gut microbial genomes. In this study, we analyzed metagenomic sequencing data from 26 donkeys' gut samples and successfully assembled 844 microbial metagenome-assembled genomes (MAGs). Surprisingly, 678 (80.33%) of these MAGs appear to belong to previously unidentified species. Our analysis further revealed a total of 292,980 predicted carbohydrate-active enzymes (CAZymes) and 257,893 polysaccharide utilization loci (PULs). Interestingly, these enzymes and loci displayed relatively low similarity matches in public databases. We found that the higher abundances of 36 MAGs in the cecum (such as Prevotella, Desulfovibrio, Alistipes, and Treponema_D) and 9 MAGs in the dorsal colon (such as Limimorpha, Saccharofermentans, and Lactobacillus) were associated with a diverse array of carbohydrate-degrading pathways. Network analysis identified Prevotella and Dysosmobacter as connectors, while Saccharofermentans and Akkermansia were shown as provincial hubs. This suggests their crucial roles in complex carbohydrate degradation and hindgut metabolism in donkeys. These findings underscore the complexity of hindgut metabolism in donkeys and expand our understanding of their gut microbiome. Overall, this study provides a comprehensive catalog of donkey gut microbial genes, revealing novel carbohydrate-degrading enzymes and offering new insights for future research on the donkey gut microbiome.

Comparative genomics of carbohydrates utilization in bacteria of the family <i>Sphaerochaetaceae</i>: evolutionary origin of the genes encoding galacturonidase and unsaturated rhamnogalacturonyl hydrolase

A comparative analysis of carbohydrate degradation proteins encoded in currently available genomic sequences of bacteria of the family Sphaerochaetaceae, namely Sphaerochaeta associata GLS2T, S. globosa BuddyT, S. pleomorpha GrapesT, S. halotolerans 4-11T, S. halotolerans 585, Sphaerochaeta sp. S2, Sphaerochaeta sp. PS and Parasphaerochaeta coccoides SPN1T was carried out. The genomes of Sphaerochaeta spp. encode a medium-sized and diverse set of proteins potentially involved in the degradation of different classes of carbohydrates, mainly oligosaccharides. All studied genomes encode glycoside hydrolases of the GH1, GH2, GH3, GH4, GH13, GH20, GH28, GH36, GH43, GH57, GH63, GH77 and GH105 families, as well as carbohydrate esterases of the CE8 and CE9 families. All studied bacteria, with the exception of P. coccoides SPN1T, have many proteins of the GH31 family encoded in their genomes. The studied representatives of Sphaerochaetaceae do not have genes coding for endo-β-acetylmuramidase (lysozyme) of the GH23 family involved in the process of peptidoglycan turnover. However, the genomes of S. associata, S. globosa, Sphaerochaeta sp. PS and S. pleomorpha contain the exo-β-acetylmuramidase gene (GH171 family). A significant part of the genes encoding carbohydrate degradation enzymes have the closest homologues among representatives of the phyla Bacillota, Bacteroidota, and Pseudomonadota. The genomes of the studied bacteria encode proteins that could potentially be involved in the degradation of pectin. The ability of representatives of Sphaerochaetaceae to use pectin for growth, as well as the evolutionary origin of genes encoding potential α-galacturonidase (GH4 family) and unsaturated glucuronyl/rhamnogalacturonyl hydrolase (GH105 family), involved in the degradation of pectin components, were studied.

Non-Targeted Metabolomics Analysis of Small Molecular Metabolites in Refrigerated Goose Breast Meat.

Poultry represents a rich source of multiple nutrients. Refrigeration is commonly employed for poultry preservation, although extended storage duration can adversely affect the meat quality. Current research on this topic has focused on the analysis of biochemical indices in chilled goose meat, with limited information on changes in metabolites that influence the quality of the meat during storage. This study used non-targeted metabolomics and the random forest algorithm to investigate metabolite changes in goose meat over an extended storage period. The results showed a significant change in the composition of the meat as the duration of storage increased, with the identification of 121 distinct metabolites. Further analysis identified 18 metabolites that could be used as indicators of the degradation of carbohydrates, amino acids, nucleotides, and lipids. These metabolites could be used as markers to monitor the deterioration process. These intermediate metabolites tended to be transformed into lower-level products involving pyruvate, acetyl coenzyme A, and fumaric acid, used in the tricarboxylic acid cycle, performing substance transformation. This comprehensive analysis of metabolites provides a valuable reference for monitoring the freshness of goose meat, potentially improving the safety of domestic poultry products.

Associations of Stool Metal Exposures with Childhood Gut Microbiome Multiomics Profiles in a Prospective Birth Cohort Study.

Metal exposures are closely related to childhood developmental health. However, their effects on the childhood gut microbiome, which also impacts health, are largely unexplored using microbiome multiomics including the metagenome and metatranscriptome. This study examined the associations of fecal profiles of metal/element exposures with gut microbiome species and active functional pathways in 8- to 12-year-old children (N = 116) participating in the GESTation and Environment (GESTE) cohort study. We analyzed 19 stool metal and element concentrations (B, Na, Mg, Al, K, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Mo, Cd, Ba, and Pb). Covariate-adjusted linear regression models identified several significant microbiome associations with continuous stool metal/element concentrations. For instance, Zn was positively associated with Turicibacter sanguinis (coef = 1.354, q-value = 0.039) and negatively associated with Eubacterium eligens (coef = -0.794, q-value = 0.044). Higher concentrations of Cd were associated with lower Eubacterium eligens (coef = -0.774, q-value = 0.045). Additionally, a total of 490 significant functional pathways such as biosynthesis and degradation/utilization/assimilation were identified, corresponding to different functions, including amino acid synthesis and carbohydrate degradation. Our results suggest links among metal exposures, pediatric gut microbiome multiomics, and potential health implications. Future work will further explore their relation to childhood health.

Inference of functional differentiation of intestinal microbes between two wild zokor species based on metagenomics.

Currently, there are fewer studies on the intestinal microbes of wild zokors, and it is unclear how zokors adapt to special underground environments by regulating their intestinal microbes. Here, we explored the function of intestinal microbes of Eospalax cansus and Eospalax rothschildi based on metagenomics. Both zokor species have similar intestinal microbial composition, but E. cansus has a higher proportion of bacteria involved in carbohydrate degradation. Functional analysis based on KEGG and CAZy databases indicated that the intestinal microbes of E. cansus harboured stronger carbohydrate degradation ability, mainly in starch and sucrose metabolism, and further in cellulose degradation. Furthermore, the cellulase activity was significantly higher in E. cansus than that in E. rothschildi. Eospalax cansus has a stronger microbial fermentation ability due to an increase in fibre-degrading bacteria like unclassified_f_Lachnospiraceae, Ruminococcus, and Clostridium. In addition, the dominant bacteria isolated from zokor were Bacillus, some of which could degrade both cellulose and hemicellulose. Metagenomic analysis and bacterial isolation experiments indicate that E. cansus has a stronger microbial cellulose-degrading capacity, possibly as an adaptation to its limited food resources underground. © 2024 Society of Chemical Industry.

Comparison of extraction process, physicochemical properties, and in vitro digestion characteristics of chia seed mucilage polysaccharide.

The study explored five (acidic, alkaline, heating, ionic liquid, and urea solvent) extraction methods' effects on chia seed mucilage polysaccharide (CSM), an anionic polymeric macromolecule, regarding its physicochemical properties, structure, and digestion behavior. The results showed that extraction parameters have a considerable effect on modulating CSM properties. Significant differences emerged in the predominant chemical compositions: the carbohydrates and protein content ranged from 49.20±0.06% to 85.81±0.03%, and 3.20±0.13% to 14.57±0.30%, respectively. The structural analysis revealed that alkaline heating treatment facilitated the formation of protein-polysaccharide conjugates, resulting in reduced particle size, enhanced ζ-potential, and improved thermal stability (194.72±2.19J/g). The crystallinity of CSM varied, peaking at 42.9±0.22% without pH adjustment and heating. CSM extracted using 6M urea exhibited the lowest protein content, and crystallinity (25.50±0.09%), coupled with the highest gastrointestinal digestion rate and poorest thermal stability (with a carbohydrate degradability of 24.223±1.78% and enthalpy value of 62.82±0.32J/g). The CSM obtained under alkaline heating showed minute particles (201.1±10.35μm), the highest ζ-potential absolute value (20.95±2.28mV), and robust thermal stability (194.72±2.19J/g of enthalpy value), which is ideal for stabilizing emulsions or encapsulating thermolabile substances. Additionally, compared to monovalent cations‑sodium ions, divalent cations‑magnesium ions, is more tend to aggregate the CSM structure, resulting in larger molecular particles and a higher protein content. Elevated ionic concentration further diminished thermal stability. These findings suggest that CSM is a customizable, multi-purpose polymer that can be extracted in various ways based on the end-product requirements.

Urban parks biowaste as a sustainable source of new antidiabetics.

Biowaste produced in urban parks is composed of large masses of organic matter that is only occasionally used economically. In this work, extracts of six plants widely distributed in urban parks in Central Europe (Achillea millefolium, Cichorium intybus, Malva sylvestris, Medicago sativa, Plantago lanceolata, and Trifolium pratense), prepared using 10 % and 50 % ethanol, were screened for their antidiabetic and related properties. HPLC and UV-Vis analysis revealed the presence of caffeic acid, quercetin, luteolin, and apigenin derivatives. The extracts were active in DPPH antiradical, .-carotene-linoleic acid, ORAC, and reducing power assay. They inhibited lipoxygenase, collagenase, as well as heat-induced ovalbumin coagulation. They were also able to hinder carbohydrate degradation. For example, IC 50 of anti-α-amylase activity of 10 % and 50 % ethanol extract of M. sativa extracts (204.10 ± 2.11 µg mL-1 and 78.27 ± 0.99 µg mL-1, respectively) did not statistically differ from the activity of the positive control, acarbose (284.74 ± 3.81 µg mL-1). Similar results were observed for their anti-.-glucosidase activity. In most assays, the use of 50 % ethanol was shown to be better suited for the extraction of active metabolites. The results indicate that the biowaste obtained from urban parks represents a potential source of plant material for the preparation of high-value antidiabetic products.

Utilizing Microbial Electrochemical Methods to Enhance Lycopene Production in Rhodopseudomonas palustris.

Utilizing Rhodopseudomonas palustris (R. pal), this study constructed a dual-chamber microbial electrosynthesis system, based on microbial electrolysis cells, that was capable of producing lycopene. Cultivation within the electrosynthesis chamber yielded a lycopene concentration of 282.3722 mg/L when the optical density (OD) reached 0.6, which was four times greater than that produced by original strains. The mutant strain showed significantly higher levels of extracted riboflavin compared to the wild-type strain, and the riboflavin content of the mutant strain was 61.081 mg/L, which was more than 10 times that of the original strain. Furthermore, sequencing and analyses were performed on the mutant strains observed during the experiment. The results indicated differences in antibiotic resistance genes, carbohydrate metabolism-related genes, and the frequencies of functional genes between the mutant and original strains. The mutant strain displayed potential advantages in specific antibiotic resistance and carbohydrate degradation capabilities, likely attributable to its adaptation to electrogenic growth conditions. Moreover, the mutant strain demonstrated an enrichment of gene frequencies associated with transcriptional regulation, signal transduction, and amino acid metabolism, suggesting a complex genetic adaptation to electrogenic environments. This study presents a novel approach for the efficient and energy-conserving production of lycopene while also providing deeper insights into the genetic basis of electro-resistance genes.

Genomic Insights into Stutzerimonas kunmingensis TFRC-KFRI-1 Isolated from Manila Clam (Ruditapes philippinarum): Functional and Phylogenetic Analysis.

Stutzerimonas kunmingensis TFRC-KFRI-1, isolated from the gut of Manila Clam in the sediment of the West Sea of Korea, was investigated for its potential as a probiotic bacterium. This strain, belonging to the family Pseudomonadaceae, was previously classified as Pseudomonas kunmingensis but later reclassified to the genus Stutzerimonas, known for species with bioremediation and probiotic properties. To evaluate its genomic features and potential applications, we performed draft-genome sequencing and analysis. The genome of S. kunmingensis TFRC-KFRI-1 was assembled into a 4,756,396 bp sequence with a 62.8% GC content. Genomic analysis suggested potential genes for carbohydrate degradation and lactic acid production. The strain exhibited high average nucleotide identity (ANI) and 16S rRNA similarity with S. kunmingensis HL22-2T, further supporting its potential as a probiotic. This genome sequence provides valuable insights into the functional capabilities of S. kunmingensis TFRC-KFRI-1 and its potential applications in various industries, including aquaculture and food biotechnology. The genome sequence is available under GenBank accession number JBGJJB000000000.1, with related project information under BioProject PRJNA1147901 and Bio-Sample SAMN43173893.

Metabolic pathways from the gut metatranscriptome are associated with COPD and respiratory function in lung cancer patients.

Changes in the human gut microbiome have been linked to various chronic diseases, including chronic obstructive pulmonary disease (COPD). While substantial knowledge is available on the genomic features of fecal communities, little is known about the microbiome's transcriptional activity. Here, we analyzed the metatranscriptomic (MTR) abundance of MetaCyc pathways, SuperPathways, and protein domain families (PFAM) represented by the gut microbiome in a cohort of non-small cell lung cancer (NSCLC) patients with- or without COPD comorbidity. Fecal samples of 40 NSCLC patients with- or without COPD comorbidity were collected at the time of diagnosis. Data was preprocessed using the Metaphlan3/Humann3 pipeline and BioCyc© to identify metabolic SuperPathways. LEfSe analysis was conducted on Pathway- and PFAM abundance data to determine COPD- and non-COPD-related clusters. Key genera Streptococcus, Escherichia, Gemella, and Lactobacillus were significantly more active transcriptionally compared to their metagenomic presence. LEfSe analysis identified 11 MetaCyc pathways that were significantly overrepresented in patients with- and without COPD comorbidity. According to Spearman's rank correlation, Smoking PY showed a significant negative correlation with Glycolysis IV, Purine Ribonucleoside Degradation and Glycogen Biosynthesis I, and a significant positive correlation with Superpathway of Ac-CoA Biosynthesis and Glyoxylate cycle, whereas forced expiratory volume in the first second (FEV1) showed a significant negative correlation with Glycolysis IV and a significant positive correlation with Glycogen Biosynthesis I. Furthermore, COPD patients showed a significantly increased MTR abundance in ~60% of SuperPathways, indicating a universally increased MTR activity in this condition. FEV1 showed a significant correlation with SuperPathways Carbohydrate degradation, Glycan biosynthesis, and Glycolysis. Taxonomic analysis suggested a more prominent MTR activity from multiple Streptococcus species, Enterococcus (E.) faecalis, E. faecium and Escherichia (E.) coli than expected from their metagenomic abundance. Multiple protein domain families (PFAMs) were identified as more associated with COPD, E. faecium, E.coli, and Streptococcus salivarius, contributing the most to these PFAMs. Metatranscriptome analysis identified COPD-related subsets of lung cancer with potential therapeutic relevance.

Metagenomic Analysis Identifies Sex-Related Gut Microbial Functions and Bacterial Taxa Associated With Skeletal Muscle Mass.

This study aimed to explore the association between gut microbiota functional profiles and skeletal muscle mass, focusing on sex-specific differences in a population under 65 years of age. Stool samples from participants were analysed using metagenomic shotgun sequencing. Skeletal muscle mass and skeletal muscle mass index (SMI) were quantified (SMI [%] = total appendage muscle mass [kg]/body weight [kg] × 100) using bioelectrical impedance analysis. Participants were categorized into SMI quartiles, and associations between gut microbiota, functional profiling and SMI were assessed by sex, adjusting for age, BMI and physical activity. The cohort included 1027 participants (651 men, 376 women). In men, Escherichia coli (log2 fold change 3.08, q = 0.001), Ruminococcus_B gnavus (log2 fold change 2.89, q = 0.014) and Enterocloster sp001517625 (log2 fold change 2.47, q = 0.026) were more abundant in the lowest SMI compared to the highest SMI group. In contrast, Bifidobacterium bifidum (log2 fold change 3.13, q = 0.025) showed higher levels in the second lowest SMI group in women. Microbial pathways associated with amino acid synthesis (MET-SAM-PWY: log2 fold change 0.42; METSYN-PWY: log2 fold change 0.44; SER-GLYSYN-PWY: log2 fold change 0.20; PWY-5347: log2 fold change 0.41; P4-PWY: log2 fold change 0.53), N-acetylneuraminate degradation (log2 fold change 0.43), isoprene biosynthesis (log2 fold change 0.20) and purine nucleotide degradation and salvage (PWY-6353: log2 fold change 0.42; PWY-6608: log2 fold change 0.38; PWY66-409: log2 fold change 0.52; SALVADEHYPOX-PWY: log2 fold change 0.43) were enriched in the lowest SMI in men (q < 0.10). In women, the second lowest SMI group showed enrichment in energy-related pathways, including lactic acid fermentation (ANAEROFRUCAT-PWY: log2 fold change 0.19), pentose phosphate pathway (PENTOSE-P-PWY: log2 fold change 0.30) and carbohydrate degradation (PWY-5484: log2 fold change 0.31; GLYCOLYSIS: log2 fold change 0.29; PWY-6901: log2 fold change 0.27) (q < 0.05). This study highlights sex-specific differences in gut microbiota and functional pathways associated with SMI. These findings suggest that gut microbiota may play a role in muscle health and point toward microbiota-targeted strategies for maintaining muscle mass.

Formation of Chlorinated Carbohydrate Degradation Products and Amino Acids during Heating of Sucralose in Model Systems and Food.

Sucralose is an artificial sweetener whose stability during the thermal treatment of food is controversially discussed. In the present work, sucralose was subjected to different kinds of heat treatment either as such, in the presence of protein, or as an ingredient of food. Compared with sucrose, sucralose showed remarkable instability and discoloration after heating at 85-90 °C for 1 h. A chlorinated furan-3-one and different chlorinated dicarbonyl compounds were identified by High-performance liquid chromatography-time-of-flight mass spectrometry (HPLC-TOF-MS) for the first time, indicating that both the 4-chlorogalactosyl residue and the 1,6-dichlorofructosyl residue give rise to novel chlorinated sugar degradation products. When sucralose was heated in the presence of protein, the formation of 3-chlorotyrosine was detected, indicating that sucralose can invoke chlorination of other biomolecules. The influence of the addition of sucralose (0.03-0.1%) to dough on pH value, color development, and HMF formation was tested in baking experiments (muffins, coconut macaroons, cookies). A significantly higher HMF concentration was observed in bakery products, including sucralose, and a chlorinated 1,2-dicarbonyl compound was detected qualitatively in baked cookies. This work shows that sucralose is not stable during baking processes at high temperatures and low moisture contents, thereby confirming recommendations from the German Institute of Risk Assessment not to use sucralose for baking.

Thermophilic dark fermentation for hydrogen and volatile fatty acids production from breadcrumbs

Food waste poses significant environmental challenges, with Japan generating 100 million kg of bread waste annually. This study explores the potential of thermophilic dark fermentation to convert bread waste into hydrogen (H2) and volatile fatty acids (VFA). A 3-L continuous stirred-tank reactor (CSTR) was operated for 269 days using breadcrumb as feedstock. The highest H2 production rate of 7.0 L-H2 L−1 d−1 was achieved on day 52 with the production of acetate and butyrate. However, H2 production fluctuated significantly, correlated with the shifts of microbial community structure. Initially, Thermoanaerobacterium saccharolyticum, Thermocoprobibacter melissae, and Anaerocolumna jejuensis coexisted, but An. jejuensis outcompeted others during the deterioration phase, resulting in acetate accumulation without H2 production. Metabolic potential analysis using the phylogenetic investigation of communities by reconstruction of unobserved states 2 (PICRUSt2) revealed that carbohydrate degradation was primarily carried out by An. jejuensis, while protein and lipid degradation involved diverse microbial members. The low functional diversity in carbohydrate degradation was a potential cause of instability. This study demonstrates the feasibility of using bread waste for H2 and VFA production, and provided insights into microbial dynamics essential for stable reactor performance.

Magnetic field effect on mechanism and syngas products of microalgae pyrolysis with activated carbon catalysts

H2-rich syngas has various applications, but it is primarily produced from fossil fuels, contributing to greenhouse gas emissions. Its conversion from renewable sources, such as biomass, can bring environmental benefits and help achieve a reduction in global temperatures below 2 °C. Biomass conversion through the thermal process offers a promising solution for syngas generation. Pyrolysis is appealing as it is more cost-effective than other thermal conversion technologies. The objective of this study is to investigate the conversion of Spirulina microalgae (SP) into syngas (CH4, H2, and CO2) using activated carbon (AC) as a catalyst under the influence of a magnetic field, employing a fixed-bed pyrolysis reactor. Characterization on raw and char SP reveals those biomasses’s main component affecting volatile population, CH4 and H2 correlated with protein and lipid decomposition; on the other hand, CO2 product depends on carbohydrates degradation. An investigation of fresh and spent AC indicates that the main catalytic interaction between pyrolysis vapor and AC is through the Van der Waals force. The magnetic field helps prevent pore blocking on AC, which is proved by specific surface analysis results indicating in a positive synergistic effect between the magnetic field and AC. Activated carbon and magnetic field affected syngas production through a series of pyrolysis vapor cracking, deoxygenation, and hydrocarbon declustering, enhancing CH4 and H2 production by 28.66 and 8.4 %, respectively, and suppressing CO2 by 28.64 % compared to SP pyrolysis alone.

Promoted formation of pyrazines by targeted precursor addition to improve aroma of thermally processed methionine-glucose Amadori compound

The methionine/glucose (Met/Glc) and methionine/glucose-derived Amadori rearrangement product (MG-ARP) models were established to analyze their differences in flavor profiles and aroma potentiality. The principal component analysis revealed the advantage of MG-ARP in the formation of low temperature-induced processing flavor. MG-ARP exhibited superior potential in the rapid formation and high intensity of processed flavor than the Met/Glc except for the inefficiency in pyrazine production. The extra-added Glc tended to react with recovered Met to compete against α-dicarbonyl compounds to suppress the Strecker degradation and pyrazine formation. The additional Met effectively improved the precursor availability and facilitated the conversion of C6-α-dicarbonyl compounds to short-chained α-dicarbonyl compounds for pyrazine formation rather than their dehydration and cyclization to generate furans. The oxidation of Met favored the nonoxidative carbohydrate degradation leading to MGO formation and the aldolization of dihydropyrazines, which synergistically enriched the varieties of pyrazines, especially for the promoted formation of long-chain substituted pyrazines.

Bacterial small RNA makes a big impact for gut colonization

The functions of non-coding small RNAs (sRNAs) within the human microbiome remain largely unexplored. In this Cell Host & Microbe issue, El Mouali etal. identify Segatella RNA colonization factor (SrcF), a sRNA from a prevalent gut bacterium Segatella copri. SrcF promotes colonization of S.copri by regulating bacterial degradation of complex dietary carbohydrates.