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Dioxygenases are enzymes involved in the conversion of polyconic aromatic hydroxycarbons (PAHs), attracting significant biotechnological interest for the conversion of recalcitrant organic compounds. Furthermore, few studies show that dioxygenases can take on the function of resistance genes in clones. This enzymatic versatility opens up new opportunities for elucidating the mechanisms of microbial resistance, as well as its biotechnological application. In this work, a Cerrado soil dioxygenase named CRB2(1) was biochemically characterized. The enzyme was shown to have optimal activity at pH 7; a temperature of 30 °C; and using iron ions as a cofactor for substrate cleavage. The kinetic catalytic parameters of CRB2(1) were V max = 0.02281 µM/min and K M = 97.6. Its predicted three-dimensional structure obtained using the Modeller software v9.22 based on the crystal structure of gentisate 1,2-dioxygenase from Silicibacter pomeroyi (GDOsp) (PDB ID 3BU7, resolution 2.80 Å, residues 17-374) revealed substrate binding to the cupin domain, where the active site is located. The analyzed substrates interact directly with the iron ion, coordinated by three histidine residues. Changing the iron ion charge modifies the binding between the active site and the substrates. Currently, there is a demand for enzymes that have biotechnological activities of interest. Metagenomics allows analyzing the biotechnological potential of several organisms at the same time, based on sequence and functional activity analyses., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Lignin is an aromatic macromolecule and one of the main constituents of lignocellulosic materials. Kraft lignin is generated as a residual by-product of the lignocellulosic biomass industrial process, and it might be used as a feedstock to generate low molecular weight aromatic compounds. In this study, we seek to understand and explore the potential of ruminal bacteria in the degradation of kraft lignin. We established two consortia, KLY and KL, which demonstrated significant lignin-degrading capabilities. Both consortia reached maximum growth after two days, with KLY showing a higher growth and decolorization rate. Additionally, SEM analysis revealed morphological changes in the residual lignin from both consortia, indicating significant degradation. This was further supported by FTIR spectra, which showed new bands corresponding to the C-H vibrations of guaiacyl and syringyl units, suggesting structural transformations of the lignin. Taxonomic analysis showed enrichment of the microbial community with members of the Dickeya genus. Seven metabolic pathways related to lignin metabolism were predicted for the established consortia. Both consortia were capable of consuming aromatic compounds such as 4-hydroxybenzoic acid, syringaldehyde, acetovanillone, and syringic acid, highlighting their capacity to convert aromatic compounds into commercially valuable molecules presenting antifungal activity and used as food preservatives as 4-hydroxyphenylacetic, 3-phenylacetic, and phenylacetic acids. Therefore, the microbial consortia shown in the present work are models for understanding the process of lignin degradation and consumption in bacterial anaerobic communities and developing biological processes to add value to industrial processes based on lignocellulosic biomass as feedstock., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Sponges from South America and Antarctica are evolutionarily closely related. Specific symbiont signatures that could differentiate these two geographic regions are unknown. This study aimed to investigate the microbiome diversity of sponges from South America and Antarctica. In total 71 sponge specimens were analyzed (Antarctica: N = 59, 13 different species; South America: N = 12, 6 different species). Illumina 16S rRNA sequences were generated (2.88 million sequences; 40K ± 29K/sample). The most abundant symbionts were heterotrophic (94.8 %) and belonged mainly to Proteobacteria and Bacteroidota. EC94 was the most abundant symbiont and dominated the microbiome of some species (70-87 %), comprising at least 10 phylogroups. Each of the EC94 phylogroups was specific to one genus or species of sponge. Furthermore, South America sponges had higher abundance of photosynthetic microorganisms (2.3 %) and sponges from Antarctica, the highest abundance of chemosynthetic (5.5 %). Sponge symbionts may contribute to the function of their hosts. The unique features from each of these two regions (e.g., light, temperature, and nutrients) possibly stimulate distinct microbiome diversity from sponges biogeographically distributed across continents., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

In this study, a GH3 family β-glucosidase (Bgl7226) from metagenomic sequences of the Syntermes wheeleri gut, a Brazilian Cerrado termite, was expressed, purified and characterized. The enzyme showed two optimum pHs (pH 7 and pH 10), and a maximum optimum temperature of about 40 °C using 4-Nitrophenyl β-D-glucopyranoside (pNPG) as substrate. Bgl7226 showed higher enzymatic activity at basic pH, but higher affinity (K m ) at neutral pH. However, at neutral pH the Bgl7226 enzyme showed higher catalytic efficiency (k cat /K m ) for pNPG substrate. Predictive analysis about the enzyme structure-function relationship by sequence alignment suggested the presence of multi-domains and conserved catalytic sites. Circular dichroism results showed that the secondary structure composition of the enzyme is pH-dependent. Small conformational changes occurred close to the optimum temperature of 40 o C, and seem important for the highest activity of Bgl7226 observed at pH 7 and 10. In addition, the small transition in the unfolding curves close to 40 o C is typical of intermediates associated with proteins structured in several domains. Bgl7226 has significant β-glucosidase activity which could be attractive for biotechnological applications, such as plant roots detoxification; specifically, our group is interested in cassava roots (Manihot esculenta) detoxification., Competing Interests: Declaration of competing interest The authors declare no conflict of interest regarding the contents of this article., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Discarded PE-based products pose a social and environmental threat because of their recalcitrance to degradation, a consequence of the unique set of PE's physicochemical properties. In this study we isolated nine novel PE-degrading bacteria from plastic debris found in soil of the savanna-like Brazilian Cerrado. These bacterial strains from the genera Comamonas, Delftia, and Stenotrophomonas showed metabolic activity and cellular viability after a 90-day incubation with PE as the sole carbon source. ATR/FTIR indicated that biodegraded PE undergone oxidation, vinylene formation, chain scission, among other chemical changes. Considerable nanoroughness shifts and vast damages to the micrometric surface were confirmed by AFM and SEM. Further, phase imaging revealed a 46.7% decrease in the viscous area of biodegraded PE whereas Raman spectroscopy confirmed a loss in its crystalline content, suggesting the assimilation of smaller fragments. Intriguingly, biodegraded PE chemical fingerprint suggests that these strains use novel biochemical strategies in the biodegradation process. Our results indicate that these microbes are capable of degrading unpretreated PE of very high molecular weight (191,000gmol -1 ) and survive for long periods under this condition, suggesting not only practical applications in waste management and environmental decontamination, but also future directions to understand the unraveled metabolism of synthetic polymers., (Copyright © 2016 Elsevier B.V. All rights reserved.)

The analysis of plant proteomes has drastically expanded in the last few years. Mass spectrometry technology, stains, software and progress in bioinformatics have made identification of proteins relatively easy. The assignment of proteins to particular organelles and the development of better algorithms to predict sub-cellular localization are examples of how proteomic studies are contributing to plant biology. Protein phosphorylation and degradation are also known to occur during plant defense signaling cascades. Despite the great potential to give contributions to the study of plant-pathogen interactions, only recently has the proteomic approach begun to be applied to this field. Biological variation and complexity in a situation involving two organisms in intimate contact are intrinsic challenges in this area, however, for proteomics studies yet, there is no substitute for in planta studies with pathogens, and ways to address these problems are discussed. Protein identification depends not only on mass spectrometry, but also on the existence of complete genome sequence databases for comparison. Although the number of completely sequenced genomes is constantly growing, only four plants have their genomes completely sequenced. Additionally, there are already a number of pathosystems where both partners in the interaction have genomes fully sequenced and where functional genomics tools are available. It is thus to be expected that great progress in understanding the biology of these pathosystems will be made over the next few years. Cheaper sequencing technologies should make protein identification in non-model species easier and the bottleneck in proteomic research should shift from unambiguous protein identification to determination of protein function., (Copyright 2009 Elsevier Ltd. All rights reserved.)