Computer-directed rational engineering of dioxygenase TcsAB for triclosan biodegradation under cold conditions.

The dioxygenase TcsAB is a specific dioxygenase involved in the initial biodegradation of the broad-spectrum antibacterial agent triclosan (TCS). However, it exhibits significantly reduced activity under cold conditions. In this study, a computer-directed approach combining loop engineering and N-terminal truncation was utilized to decrease the thermostability of TcsAB, thereby enhancing its catalytic activity in cold environments.

Proline mitigates antibiotic resistance evolution induced by ciprofloxacin at environmental concentrations.

Antibiotics-induced resistance development in the environment has emerged as a critical issue under the 'one health' framework. Although there have been approaches to control antibiotic resistance evolution in clinical settings, they are rarely applicable in environmental contexts. Amino acids can affect the metabolic states of bacteria and potentially influence their resistance evolution.

Unveiling triclosan biodegradation: Novel metabolic pathways, genomic insights, and global environmental adaptability of Pseudomonas sp. strain W03.

The polychlorinated aromatic antimicrobial agent triclosan (TCS) is widely used to indiscriminately and rapidly kill microorganisms. The global use of TCS has led to widespread environmental contamination, posing significant threats to ecosystem and human health. Here we reported a newly isolated Pseudomonas sp.

Integration of metagenomic analysis and metabolic modeling reveals microbial interactions in activated sludge systems in response to nanoplastics and plasticizers.

Nanoplastics and plasticizers are prevalent in activated sludge and pose a potential threat to microbial communities in wastewater treatment systems. However, studies on the effects of nanoplastics and plasticizers on the interaction mechanisms and metabolic functions of microbial communities in activated sludge systems are still scarce. In this study, the responses of microbial interactions and metabolic functions to PVC nanoplastics (PVCNPs) and bis(2-ethylhexyl) phthalate (DEHP) in activated sludge were investigated via a combination of amplicon sequencing, metagenome sequencing, and metabolic modeling.

Genome streamlining of B6-2 for bioremediation.

Microbial transformation is a favored approach for environmental remediation. However, the effectiveness of microbial remediation has been limited by the lack of chassis cells with satisfactory contaminant degradation performance. B6-2, with a wide substrate spectrum and high solvent tolerance, is a chassis strain with great potential for application in environmental remediation.

Interspecies synergistic interactions mediated by cofactor exchange enhance stress tolerance by inducing biofilm formation.

Unlabelled: Metabolic exchange plays a crucial role in shaping microbial community interactions and functions, including the exchange of small molecules such as cofactors. Cofactors are fundamental to enzyme catalytic activities; however, the role of cofactors in microbial stress tolerance is unclear. Here, we constructed a synergistic consortium containing two strains that could efficiently mineralize di-(2-ethylhexyl) phthalate under hyperosmotic stress.

Resting for viability: Gordonia polyisoprenivorans ZM27, a robust generalist for petroleum bioremediation under hypersaline stress.

The intrinsic issue associated with the application of microbes for practical pollution remediation involves maintaining the expected activity of engaged strains or consortiums as effectively as that noted under laboratory conditions. Faced with various stress factors, degraders with dormancy ability are more likely to survive and exhibit degradation activity. In this study, a hydrocarbonoclastic and halotolerant strain, Gordonia polyisoprenivorans ZM27, was isolated via stimulation with resuscitation-promoting factor (Rpf).

Triclosan Dioxygenase: A Novel Two-component Rieske Nonheme Iron Ring-hydroxylating Dioxygenase Initiates Triclosan Degradation.

The emerging contaminant triclosan (TCS) is widely distributed both in surface water and in wastewater and poses a threat to aquatic organisms and human health due to its resistance to degradation. The dioxygenase enzyme TcsAB has been speculated to perform the initial degradation of TCS, but its precise catalytic mechanism remains unclear. In this study, the function of TcsAB was elucidated using multiple biochemical and molecular biology methods.

sRNA molecules participate in hyperosmotic stress response regulation in TY.

Drought and salinity are ubiquitous environmental factors that pose hyperosmotic threats to microorganisms and impair their efficiency in performing environmental functions. However, bacteria have developed various responses and regulatory systems to cope with these abiotic challenges. Posttranscriptional regulation plays vital roles in regulating gene expression and cellular homeostasis, as hyperosmotic stress conditions can lead to the induction of specific small RNA molecules (sRNAs) that participate in stress response regulation.

sp. nov. and sp. nov., two members of the phylum isolated from the wastewater treatment system of a pharmaceutical factory.

Five strains of two novel species were isolated from the wastewater treatment systems of a pharmaceutical factory located in Zhejiang province, PR China. Strains ZM22 and Y6 were identified as belonging to a potential novel species of the genus , whereas strains ZM23, ZM24 and ZM25 were identified as belonging to a novel species of the genus . These strains were characterized by polyphasic approaches including 16S rRNA gene analysis, multi-locus sequence analysis, average nucleotide identity (ANI), DNA-DNA hybridization (DDH), physiological and biochemical tests, as well as chemotaxonomic analysis.

A multicomponent propane monooxygenase catalyzes the initial degradation of methyl -butyl ether in JOB5.

Methyl -butyl ether (MTBE) has been recognized as a groundwater contaminant due to its widespread distribution and potential threat to human health. The limited understanding of the enzymes catalyzing MTBE degradation restricts their application in MTBE bioremediation. In this study, an MTBE-degrading soluble di-iron monooxygenase that clusters phylogenetically with a known propane monooxygenase (PRM) encoded by the gene cluster was identified and functionally characterized, revealing their role in MTBE metabolism by JOB5.

Granule Dendrobii suppresses chronic atrophic gastritis induced by N-methyl-N'-nitro-N-nitrosoguanidine by modulating the gastrointestinal bacteria in rats.

Chronic atrophic gastritis (CAG) is an important stage in the transformation of the normal gastric mucosa into gastric cancer. Granule Dendrobii (GD), a proprietary Chinese medicine, has proven clinical efficacy in treating CAG. GD might promote the reversal of precancerous lesions by improving them in CAG patients.

Ribosomal RNA gene operon copy number, a functional trait indicating the hydrocarbon degradation level of bacterial communities.

The lack of universal indicators for predicting microbial biodegradation potential and assessing remediation effects limits the generalization of bioremediation. The community-level ribosomal RNA gene operon (rrn) copy number, an important functional trait, has the potential to serve as a key indicator of the bioremediation of organic pollutants. A meta-analysis based on 1275 samples from 26 hydrocarbon-related studies revealed a positive relationship between the microbial hydrocarbon biodegradation level and the community-level rrn copy number in soil, seawater and culture.

Characterization of Hsp17, a Novel Small Heat Shock Protein, in Sphingomonas melonis TY under Heat Stress.

Bacteria are constantly exposed to a variety of environmental stresses. Temperature is considered one of the most important environmental factors affecting microbial growth and survival. As ubiquitous environmental microorganisms, species play essential roles in the biodegradation of organic contaminants, plant protection, and environmental remediation.

Thiamine-Mediated Microbial Interaction between Auxotrophic Rhodococcus ruber ZM07 and Prototrophic Cooperators in the Tetrahydrofuran-Degrading Microbial Community H-1.

As a crucial growth factor, thiamine can regulate functional microbial communities; however, our current understanding of its effect on bioremediation is lacking. Using metatranscriptome and 16S rRNA gene sequencing, we explored the mechanism of response of an efficient tetrahydrofuran (THF)-degrading microbial culture, designated H-1, to exogenous thiamine. Rhodococcus ruber ZM07, a strain performing the THF degradation function in H-1, is a thiamine-auxotrophic bacterium.

Regulation Mechanism of Nicotine Catabolism in Sphingomonas melonis TY by a Dual Role Transcriptional Regulator NdpR.

A gene cluster , responsible for nicotine degradation via a variant of the pyridine and pyrrolidine pathways, was previously identified in Sphingomonas melonis TY, but the regulation mechanism remains unknown. The gene within the cluster was predicted to encode a TetR family transcriptional regulator. Deletion of resulted in a notably shorter lag phase, higher maximum turbidity, and faster substrate degradation when cultivated in the presence of nicotine.

Global transcriptional and translational regulation of Sphingomonas melonis TY in response to hyperosmotic stress.

Hyperosmotic stress is one of the most ubiquitous stress factors in microbial habitats and impairs the efficiency of bacteria performing vital biochemical tasks. Sphingomonas serves as a 'superstar' of plant defense and pollutant degradation, and is widely existed in the environment. However, it is still unclear that how Sphingomonas sp.

Degradation of Triclosan in the Water Environment by Microorganisms: A Review.

Triclosan (TCS), a kind of pharmaceuticals and personal care products (PPCPs), is widely used and has had a large production over years. It is an emerging pollutant in the water environment that has attracted global attention due to its toxic effects on organisms and aquatic ecosystems, and its concentrations in the water environment are expected to increase since the COVID-19 pandemic outbreak. Some researchers found that microbial degradation of TCS is an environmentally sustainable technique that results in the mineralization of large amounts of organic pollutants without toxic by-products.

Nutritional stress induced intraspecies competition revealed by transcriptome analysis in Sphingomonas melonis TY.

Bacteria have developed various mechanisms by which they can compete or cooperate with other bacteria. This study showed that in the cocultures of wild-type Sphingomonas melonis TY and its isogenic mutant TYΔndpD grow with nicotine, the former can outcompete the latter. TYΔndpD undergoes growth arrest after four days when cocultured with wild-type TY, whereas the coculture has just entered a stationary phase and the substrate was nearly depleted, and the interaction between the two related strains was revealed by transcriptomic analysis.

Microbial interactions enhanced environmental fitness and expanded ecological niches under dibutyl phthalate and cadmium co-contamination.

Co-contamination of organic pollutants and heavy metals is universal in the natural environment. Dibutyl phthalate (DBP), a typical plasticizer, frequently coexists with cadmium (Cd) in nature. However, little attention has been given to the impacts of co-contamination by DBP and Cd on microbial communities or the responses of microbes.

Network and meta-omics reveal the cooperation patterns and mechanisms in an efficient 1,4-dioxane-degrading microbial consortium.

1,4-Dioxane is an emerging wastewater contaminant with probable human carcinogenicity. Our current understanding of microbial interactions during 1,4-dioxane biodegradation process in mixed cultures is limited. Here, we applied metagenomic, metatranscriptomic and co-occurrence network analyses to unraveling the microbial cooperation between degrader and non-degraders in an efficient 1,4-dioxane-degrading microbial consortium CH1.

A Multicomponent THF Hydroxylase Initiates Tetrahydrofuran Degradation in ZM02.

Tetrahydrofuran (THF) has been recognized as a water contaminant because of its human carcinogenicity, extensive use, and widespread distribution. Previously reported multicomponent monooxygenases (MOs) involved in THF degradation were highly conserved, and all of them were from Gram-positive bacteria. In this study, a novel THF-degrading gene cluster () encoding THF hydroxylase was identified on the chromosome of a newly isolated Gram-negative THF-degrading bacterium, Cupriavidus metallidurans ZM02, and functionally characterized.

ZM06 Assists ZM05 in Resisting Cadmium Pressure to Preserve Dipropyl Phthalate Biodegradation.

Dipropyl phthalate (DPrP) coexists with cadmium as cocontaminants in environmental media. A coculture system including the DPrP-degrading bacterium ZM05 and the nondegrading bacterium ZM06 was artificially established to degrade DPrP under Cd(II) stress. Strain ZM06 relieved the pressure of cadmium on strain ZM05 and accelerated DPrP degradation in the following three ways: first, strain ZM06 adsorbed Cd(II) on the cell surface (as observed by scanning electron microscopy) to decrease the concentration of Cd(II) in the coculture system; second, the downstream metabolites of ZM05 were utilized by strain ZM06 to reduce metabolite inhibition; and third, strain ZM06 supplied amino acids and fatty acids to strain ZM05 to relieve stress during DPrP degradation, which was demonstrated by comparative transcriptomic analysis.

Efficient electrotransformation of Rhodococcus ruber YYL with abundant extracellular polymeric substances via a cell wall-weakening strategy.

Rhodococcus spp. have broad potential applications related to the degradation of organic contaminants and the transformation or synthesis of useful compounds. However, some Gram-positive bacteria are difficult to manipulate genetically due to low transformation efficiency.

Thiamine-Mediated Cooperation Between Auxotrophic ZM07 and K12 Drives Efficient Tetrahydrofuran Degradation.

Tetrahydrofuran (THF) is a universal solvent widely used in the synthesis of chemicals and pharmaceuticals. As a refractory organic contaminant, it can only be degraded by a small group of microbes. In this study, a thiamine auxotrophic THF-degrading bacterium, ZM07, was isolated from an enrichment culture H-1.