Genetic bioaugmentation with triclocarban-catabolic plasmid effectively removes triclocarban from wastewater

Rapid screening of indigenous degrading microorganisms for enhancing in-situ bioremediation of organic pollutants-contaminated soil

Organic pollutants (OPs) have caused severe environmental contaminations in the world and aroused wide public concern. Autochthonous bioaugmentation (ABA) is considered a reliable bioremediation approach for OPs contamination. However, the rapid screening of indigenous degrading strains from in-situ environments remains a primary challenge for the practical application of ABA. In this study, 3,5,6-Trichloro-2-pyridinol (TCP, an important intermediate in the synthesis of various pesticides) was selected as the target OPs, and DNA stable isotope probing (DNA-SIP) combined with high-throughput sequencing was employed to explore the rapid screening of indigenous degrading microorganisms. The results of DNA-SIP revealed a significant enrichment of OTU557 (Cupriavidus sp.) in the 13C-TCP-labeled heavy DNA fractions, indicating that it is the key strain involved in TCP metabolism. Subsequently, an indigenous TCP degrader, Cupriavidus sp. JL-1, was rapidly isolated from native soil based on the analysis of the metabolic substrate spectrum of Cupriavidus sp. Furthermore, ABA of strain JL-1 demonstrated higher remediation efficacy and stable survival compared to the exogenous TCP-degrading strain Cupriavidus sp. P2 in in-situ TCP-contaminated soil. This study presents a successful case for the rapid acquisition of indigenous TCP-degrading microorganisms to support ABA as a promising strategy for the in-situ bioremediation of TCP-contaminated soil.

Degradation of polyethylene terephthalate (PET) plastics by wastewater bacteria engineered via conjugation

Wastewater treatment plants are one of the major pathways for microplastics to enter the environment. In general, microplastics are contaminants of global concern that pose risks to ecosystems and human health. Here, we present a proof-of-concept for reduction of microplastic pollution emitted from wastewater treatment plants: delivery of recombinant DNA to bacteria in wastewater to enable degradation of polyethylene terephthalate (PET). Using a broad-host-range conjugative plasmid, we enabled various bacterial species from a municipal wastewater sample to express FAST-PETase, which was released into the extracellular environment. We found that FAST-PETase purified from some transconjugant isolates could degrade about 40% of a 0.25 mm thick commercial PET film within 4 days at 50°C. We then demonstrated partial degradation of a post-consumer PET product over 5-7 days by exposure to conditioned media from isolates. These results have broad implications for addressing the global plastic pollution problem by enabling environmental bacteria to degrade PET.

Yanghanlia caeni gen. nov., sp. nov., a novel taxon within the family Alcaligenaceae isolated from sludge of a pesticide-manufacturing factory

A Gram-stain-negative bacterium, designated LG-2T, was isolated from sludge collected at a pesticide-manufacturing factory in Jiangsu Province, PR China. Cells of strain LG-2T were strictly aerobic, non-motile and spherical. Growth was observed at 15-42 °C (optimum, 30 °C), pH 6.0-9.0 (optimum, pH 7.0) and 0-3.0 % (w/v) NaCl (optimum, 1.0 %). LG-2T showed 95.5-96.9 % 16S rRNA sequence similarity to type strains in the genera Pusillimonas, Bordetella, Parapusillimonas, Candidimonas and Paracandidimonas of the family Alcaligenaceae. The phylogenomic tree indicated that strain LG-2T was clustered in the family Alcaligenaceae and formed a clade with Paracandidimonas soli IMT-305T, while the phylogenetic trees based on 16S rRNA gene sequences indicated that strain LG-2T formed a distinct clade within the family Alcaligenaceae. The average nucleotide identity, digital DNA-DNA hybridization and average amino acid identity values between LG-2T and its closely related type strains in the genera Pusillimonas, Bordetella, Parapusillimonas, Candidimonas and Paracandidimonas were 70.8-75.3, 18.9-23.7 and 59.6 %-69.3 %, respectively. The major cellular fatty acids were C16 : 0, C17 : 0 cyclo, summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c), summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c) and summed feature 2 (C12 : 0 aldehyde and/or unknown 10.928). The predominant menaquinone was Q-8. The polar lipid profile consisted of phosphatidylethanolamine, phosphatidylglycerol, two aminophospholipids, three aminolipids and nine unknown polar lipids. The genome size of strain LG-2T was 3.2 Mb and the DNA G+C content was 63.4 mol%. On the basis of the phenotypic, phylogenetic and genomic results from this study, strain LG-2T represents a novel species of a new genus in the family Alcaligenaceae, for which the name Yanghanlia caeni gen. nov., sp. nov. is proposed, with strain LG-2T (=KCTC 8084T= CCTCC AB 2023123T) as the type strain.

Current strategies on bioremediation of personal care products and detergents: Sustainability and life cycle assessment

The increased use of personal care products and detergents in modern society has raised concerns about their potential adverse effects on the environment. These products contain various chemical compounds that can persist in water bodies, leading to water pollution and ecological disturbances. Bioremediation has emerged as a promising approach to address these challenges, utilizing the natural capabilities of microorganisms to degrade or remove these contaminants. This review examines the current strategies employed in the bioremediation of personal care products and detergents, with a specific focus on their sustainability and environmental impact. This bioremediation is essential for environmental rejuvenation, as it uses living organisms to detergents and other daily used products. Its distinctiveness stems from sustainable, nature-centric ways that provide eco-friendly solutions for pollution eradication and nurturing a healthy planet, all while avoiding copying. Explores the use of microbial consortia, enzyme-based treatments, and novel biotechnological approaches in the context of environmental remediation. Additionally, the ecological implications and long-term sustainability of these strategies are assessed. Understanding the strengths and limitations of these bioremediation techniques is essential for developing effective and environmentally friendly solutions to mitigate the impact of personal care products and detergents on ecosystems.

Paenibacillus glufosinatiresistens sp. nov., a glufosinate-resistant bacterium isolated from sludge

A Gram-stain-positive bacterium capable of resisting 5.0 mM glufosinate, designated strain YX-27T, was isolated from a sludge sample collected from a factory in Wuxi, Jiangsu, PR China. Cells were rod-shaped, facultatively anaerobic, endospore-forming, and motile by peritrichous flagella. Growth was observed at 15-42 °C (optimum at 30 °C), pH 4.0-8.0 (optimum pH 7.0-7.5) and with 0-2.5% NaCl (w/v; optimum, 0.5 %). Strain YX-27T could tolerate up to 6.0 mM glufosinate. Strain YX-27T showed the highest 16S rRNA gene sequence similarity to Paenibacillus tianjinensis TB2019T (96.17 %), followed by Paenibacillus odorifer DSM 1539T (96.15 %), Paenibacillus sophorae S27T (96.04 %), Paenibacillus apii 7124T (96.02 %) and Paenibacillus stellifer DSM 14472T (95.87 %). The phylogenetic tree based on genome and 16S rRNA gene sequences indicated that strain YX-27T was clustered in the genus Paenibacillus but formed a separate clade. The genome size of YX-27T was 5.22 Mb with a G+C content of 57.5 mol%. The average nucleotide identity and digital DNA-DNA hybridization values between the genomes of strain YX-27T and 12 closely related type strains ranged from 70.8 to 74.8% and 19.8 to 23.0 %, respectively. The major cellular fatty acids were C16 : 0, anteiso-C15 : 0 and iso-C16 : 0. The major polar lipids were one diphosphatidylglycerol, one phosphatidylethanolamine, one phosphatidylglycerol, one phospholipid, four aminophospholipids and four unidentified lipids. The predominant respiratory quinone was MK-7. Based on phylogenetic, genomic, chemotaxonomic and phenotypic data, strain YX-27T was considered to represent a novel species for which the name Paenibacillus glufosinatiresistens sp. nov. is proposed, with YX-27T (=MCCC 1K08803T= KCTC 43611T) as the type strain.

Bacterial growth and environmental adaptation via thiamine biosynthesis and thiamine-mediated metabolic interactions

Understanding the ancestral transition from anaerobic to aerobic lifestyles is essential for comprehending life's early evolution. However, the biological adaptations occurring during this crucial transition remain largely unexplored. Thiamine is an important cofactor involved in central carbon metabolism and aerobic respiration. Here, we explored the phylogenetic and global distribution of thiamine-auxotrophic and thiamine-prototrophic bacteria based on the thiamine biosynthetic pathway in 154 838 bacterial genomes. We observed strong coincidences of the origin of thiamine-synthetic bacteria with the "Great Oxygenation Event," indicating that thiamine biosynthesis in bacteria emerged as an adaptation to aerobic respiration. Furthermore, we demonstrated that thiamine-mediated metabolic interactions are fundamental factors influencing the assembly and diversity of bacterial communities by a global survey across 4245 soil samples. Through our newly established stable isotope probing-metabolic modeling method, we uncovered the active utilization of thiamine-mediated metabolic interactions by bacterial communities in response to changing environments, thus revealing an environmental adaptation strategy employed by bacteria at the community level. Our study demonstrates the widespread thiamine-mediated metabolic interactions in bacterial communities and their crucial roles in setting the stage for an evolutionary transition from anaerobic to aerobic lifestyles and subsequent environmental adaptation. These findings provide new insights into early bacterial evolution and their subsequent growth and adaptations to environments.

Thermodynamic Assessment of Triclocarban Dissolution Process in N-Methyl-2-pyrrolidone + Water Cosolvent Mixtures

Solubility is one of the most important physicochemical properties due to its involvement in physiological (bioavailability), industrial (design) and environmental (biotoxicity) processes, and in this regard, cosolvency is one of the best strategies to increase the solubility of poorly soluble drugs in aqueous systems. Thus, the aim of this research is to thermodynamically evaluate the dissolution process of triclocarban (TCC) in cosolvent mixtures of {N-methyl-2-pyrrolidone (NMP) + water (W)} at seven temperatures (288.15, 293.15, 298.15, 303.15, 308.15, 313.15 and 318.15 K). Solubility is determined by UV/vis spectrophotometry using the flask-shaking method. The dissolution process of the TCC is endothermic and strongly dependent on the cosolvent composition, achieving the minimum solubility in pure water and the maximum solubility in NMP. The activity coefficient decreases from pure water to NMP, reaching values less than one, demonstrating the excellent positive cosolvent effect of NMP, which is corroborated by the negative values of the Gibbs energy of transfer. In general terms, the dissolution process is endothermic, and the increase in TCC solubility may be due to the affinity of TCC with NMP, in addition to the water de-structuring capacity of NMP generating a higher number of free water molecules.

Experimental and computational approaches to characterize a novel amidase that initiates the biodegradation of the herbicide propanil in Bosea sp. P5

The herbicide propanil and its major metabolite 3,4-dichloroaniline (3,4-DCA) are difficult to biodegrade and pose great health and environmental risks. However, studies on the sole or synergistic mineralization of propanil by pure cultured strains are limited. A two-strain consortium (Comamonas sp. SWP-3 and Alicycliphilus sp. PH-34), obtained from a swep-mineralizing enrichment culture that can synergistically mineralize propanil, has been previously reported. Here, another propanil degradation strain, Bosea sp. P5, was successfully isolated from the same enrichment culture. A novel amidase, PsaA, responsible for initial propanil degradation, was identified from strain P5. PsaA shared low sequence identity (24.0-39.7 %) with other biochemically characterized amidases. PsaA exhibited optimal activity at 30 °C and pH 7.5 and had k_cat and K_m values of 5.7 s^-1 and 125 μM, respectively. PsaA could convert the herbicide propanil to 3,4-DCA but exhibited no activity toward other herbicide structural analogs. This catalytic specificity was explained by using propanil and swep as substrates and then analyzed by molecular docking, molecular dynamics simulation and thermodynamic calculations, which revealed that Tyr138 is the key residue that affects the substrate spectrum of PsaA. This is the first propanil amidase with a narrow substrate spectrum identified, providing new insights into the catalytic mechanism of amidase in propanil hydrolysis.