Search Results (57)

Pesticides remain indispensable for modern agriculture, yet their persistence in soil poses serious ecological and human-health risks through bioaccumulation, groundwater contamination, and impacts on non-target organisms. Although extensive research exists on pesticide degradation, most reviews separate biochemical pathways, environmental controls, and applied bioremediation strategies, limiting the ability to predict real-world field performance. This review integrates mechanistic enzymology, soil ecological responses, quantitative degradation kinetics, and emerging synthetic biology innovations into one unified framework. Soil bacteria including Pseudomonas, Bacillus, Rhodococcus, and Arthrobacter degrade organophosphates, carbamates, triazines, neonicotinoids, pyrethroids, and organochlorines through hydrolysis, oxidation, nitroreduction, and ring-cleavage pathways, often supported by plasmid-encoded genes and horizontal gene transfer. Bioaugmented systems typically achieve 70 to 95 percent removal within 10 to 30 days, with highly efficient cases such as Pseudomonas putida KT2440 removing 96 percent chlorpyrifos in 5 days, Rhodococcus koreensis mineralizing 98 percent endosulfan in 7 days, and Arthrobacter sp. AD26 degrading 95 percent atrazine in 72 h. Field-scale Azotobacter–Pseudomonas consortia have reduced chlorpyrifos from 25 mg kg⁻¹ to less than 1 mg kg⁻¹ within 30 days. Environmental conditions strongly influence degradation efficiency. Acidic soils increase pyrethroid half-lives by two to three times, anaerobic conditions can extend pesticide persistence from months to years, and drought or low organic matter reduces microbial activity by 60 to 80 percent, increasing neonicotinoid DT₅₀ to more than 1000 days. Advances in omics, metagenomics, kinetic assays, and synthetic biology now enable engineered strains and synthetic consortia capable of more than 90 percent mineralization within 7 to 21 days. By linking molecular mechanisms, ecological constraints, quantitative outcomes, and emerging biotechnologies, this review provides a predictive roadmap for climate-resilient, scalable, and sustainable bioremediation strategies. Full article

Atopic dermatitis (AD) is a chronic inflammatory skin disorder characterized by dysregulated immunity, skin barrier dysfunction, and cutaneous microbiome dysbiosis. While current therapies face limitations, Thuja sutchuenensis essential oil (TEO) shows promise due to its multi-target potential. We sought to explore the beneficial effects of TEO and delve into its mechanistic actions in a mouse model of AD. We combined network pharmacology with in vivo validation to evaluate the therapeutic efficacy and mechanisms of TEO in an AD model, and confirmed network-predicted targets in an in vitro inflammatory cell model. In AD mice, TEO alleviated pruritus and epidermal hyperplasia, suppressed systemic IL-4/TNF-α and IgE, and partially normalized serum ALB, LDL-C, and HDL-C. Microbial diversity increased after treatment, although potentially pathogenic taxa (Arthrobacter sp. and Corynebacterium mastitidis) remained enriched. Machine-learning analysis indicated the highest predicted metabolic activity in CK controls, whereas the AD and TEO groups showed elevated pathogenic phenotype scores. Network pharmacology prioritized active compounds [(E)-ligustilide, senkyunolide A, 3-butylisobenzofuran-1(3H)-one, butylated hydroxytoluene, Z-buthlidenephthalide, and β-Myrcene] and core targets (TNF, PTPRC, CCR5, JAK1), implicating T-cell receptor signaling, Staphylococcus aureus infection, and STAT3 pathways. Docking and molecular dynamics supported strong, stable binding of major constituents to JAK1, and Western blotting confirmed TEO-mediated inhibition of the JAK1/STAT3 axis. TEO effectively alleviates atopic dermatitis symptoms by modulating immune responses and enhancing microbial diversity. It targets key signaling pathways, such as JAK1/STAT3, highlighting its potential as a therapeutic option for AD. Full article

With the rise of environmental protection and health topics in recent years, microbial production of red pigments has gradually become a research hotspot. Red pigment possesses biological properties such as anticancer and antioxidant activities and has a wide range of potential applications in the fields of food and medicine. In this paper, a red pigment-producing strain was screened from rice soil to provide a reserve for obtaining natural and safe red pigments. Methods: The strain LSY1-2 was identified using morphological and 16S rDNA molecular biological identification. The fermentation conditions for red pigment production were optimised to improve pigment yield, and the best conditions were analysed using response surface methodology. Finally, the stabilisation conditions of red pigment were analysed to determine the difficulty of retention. Results: The molecular ecology was identified as the bacterium Arthrobacter sp. of the genus Arthrobacter. The optimal red pigment production medium for the strain was determined by a one-way test with the carbon source beef extract, the nitrogen source peptone, the inoculum size 2%, the temperature 27 °C, the pH value 7, and the rotational speed 160 rpm. Response surface optimisation determined the optimal red pigment production conditions as the incubation temperature of 26.43 °C, the pH value of 6.89, and the rotational speed of 162.77 rpm, which resulted in the yield of red pigment under these optimal conditions as 0.883 U/mL. The stability of red pigment was best under the condition without light, and poorer under conditions of above 50 °C, strong acid, strong alkali, and more than 3% oxidant, and Fe³⁺ had a greater effect on the stability. Conclusions: Strain LSY-1 can produce stable red pigment under the optimised red pigment-producing conditions, which provides a reference for the large-scale production of natural red pigment and subsequent related research. Full article

Glycyrrhiza uralensis (G. uralensis), a leguminous plant, is an important medicinal and economic plant in saline–alkaline soils of arid regions in China. Its main bioactive components include liquiritin, glycyrrhizic acid, and flavonoids, which play significant roles in maintaining human health and preventing and adjuvantly treating related diseases. However, the cultivation of G. uralensis is easily restricted by adverse soil conditions in these regions, characterized by high salinity, high alkalinity, and nutrient deficiency. This study investigated the impacts of four multistrain microbial inoculants (Pa, Pb, Pc, Pd) on the growth performance and bioactive compound accumulation of G. uralensis in moderately saline–sodic soil. The aim was to screen the most beneficial inoculant from these strains, which were isolated from the rhizosphere of plants in moderately saline–alkaline soils of the Hexi Corridor and possess native advantages with excellent adaptability to arid environments. The results showed that inoculant Pc, comprising Pseudomonas silesiensis, Arthrobacter sp. GCG3, and Rhizobium sp. DG1, exhibited superior performance: it induced a 0.86-unit reduction in lateral root number relative to the control, while promoting significant increases in single-plant dry weight (101.70%), single-plant liquiritin (177.93%), single-plant glycyrrhizic acid (106.10%), and single-plant total flavonoids (107.64%). Application of the composite microbial inoculant Pc induced no significant changes in the pH and soluble salt content of G. uralensis rhizospheric soils. However, it promoted root utilization of soil organic matter and nitrate, while significantly increasing the contents of available potassium and available phosphorus in the rhizosphere. High-throughput sequencing revealed that Pc reorganized the rhizospheric microbial communities of G. uralensis, inducing pronounced shifts in the relative abundances of rhizospheric bacteria and fungi, leading to significant enrichment of target bacterial genera (Arthrobacter, Pseudomonas, Rhizobium), concomitant suppression of pathogenic fungi, and proliferation of beneficial fungi (Mortierella, Cladosporium). Correlation analyses showed that these microbial shifts were linked to improved plant nutrition and secondary metabolite biosynthesis. This study highlights Pc as a sustainable strategy to enhance G. uralensis yield and medicinal quality in saline–alkali ecosystems by mediating microbe–plant–nutrient interactions. Full article

Cold-adapted microorganisms possess cold-active enzymes with potential applications in different industries and research areas. In this study, two genes encoding β-d-galactosidases belonging to Glycoside Hydrolase families 2 and 42 from the psychrotolerant Arctic bacterium Arthrobacter sp. S3* were cloned, expressed in Escherichia coli and Komagataella phaffii, purified and characterized. The GH2 β-d-galactosidase is a tetramer with a molecular weight of 450 kDa, while the GH42 β-d-galactosidase is a 233 kDa trimer. The Bgal2 was optimally active at pH 7.5 and 22 °C and maintained 57% of maximum activity at 10 °C, whereas the Bgal42 was optimally active at pH 7.0 and 40 °C and exhibited 44% of maximum activity at 10 °C. Both enzymes hydrolyzed lactose and showed transglycosylation activity. We also found that 2 U/mL of the Bgal2 hydrolyzed 85% of lactose in milk within 10 h at 10 °C. The enzyme synthesized galactooligosaccharides, heterooligosaccharides, alkyl galactopyranosides and glycosylated salicin. The Bgal42 synthesized galactooligosaccharides and 20 U/mL of the enzyme hydrolyzed 72% of milk lactose within 24 h at 10 °C. The properties of Arthrobacter sp. S3* Bgal2 make it a candidate for lactose hydrolysis in the dairy industry and a promising tool for the glycosylation of various acceptors in the biomedical sector. Full article

The aim of this research was to study the effect of plant-growth-promoting bacteria (PGPB) isolated from the drought-tolerant plants camel thorn (Alhagi pseudoalhagi (M.Bieb.) Fisch) and white pigweed (Chenopodium album L.) on wheat (Triticum aestivum L.) plants cv. Lenigradskaya 6, growing under hydroponic conditions and osmotic stress (generated by 12% polyethylene glycol-6000 (PEG)). Based on the assumption that plants create a unique microbiome that helps them overcome various stresses, we hypothesized that bacteria isolated from drought-tolerant plants may assist cultivated wheat plants in coping with drought stress. PGPB were isolated from seeds and leaves of plants and identified as Bacillus spp. (strains Cap 07D, Cap 09D, and App 11D); Paenibacillus sp. (Cap 286); and Arthrobacter sp. (Cap 03D). All bacteria produced different phytohormones such as indole acetic acid (IAA), abscisic acid (ABA), and gibberellic acid (GAS₃) and were capable of stimulating wheat growth under normal and osmotic stress conditions. All PGPB reduced the malondialdehyde (MDA) content, increased the total chlorophyll content by increasing chlorophyll a, and modulated wheat hormone homeostasis and CAT and POX activities under osmotic conditions. Selected strains can be promising candidates for the mitigating of the drought stress of wheat plants. Full article

To elucidate the biological mechanisms driving the growth of various pumpkin varieties to different sizes under identical management conditions while in the same field, the soil microbial community structures in the rhizospheres of giant-pumpkin (GP) and small-pumpkin (SP) varieties were analyzed. The results revealed that a significantly higher abundance of bacterial communities could be detected in the rhizospheres of the giant pumpkin varieties, such as Gemmatimonadota, norank__f__norank__o_Gaiellales, norank__f__Gemmatimonadaceae, Bryobacter, Sphingomonas, norank__f__JG30-KF-AS9, and norank__f__norank__o___Elsterales, than in those of the small-sized pumpkins. Additionally, norank_f__norank_o__Elsterale, Ellin6067, norank_f__67-14, and Chujaibacter were unique dominant soil bacteria genera in the rhizospheres of the giant pumpkins. By contrast, Arthrobacter, norank_f__Roseiflexaceae, unclassified_f__Rhizobiaceae, Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium, Nocardioides, Mycobacterium, norank_f__norank_o__Vicinamibacterales, and Burkholderia-Caballeronia-Paraburkholderia were the unique dominant soil bacterial genera in the rhizospheres of the small pumpkins. Moreover, at the fungal genus level, unclassified_c__Chytridiomycetes, Podosphaera, and Colletotrichum presented significant differences between the giant-pumpkin (GP) and small-pumpkin (SP) rhizospheres. In addition, unclassified__p__Rozellomycota, unclassified__c__Chytridiomycetes, Penicillium, and unclassified__f__Chaetomiaceae were unique dominant soil fungal genera in the rhizospheres of the giant pumpkins (GPs). By contrast, Podosphaera, Colletotrichum, unclassified__f__Plectosphaerellaceae, unclassified__o_Boletales, Scytalidium, unclassified__p__Rozellomycota, and unclassified__o_Agaricales were the unique dominant soil fungal genera in the rhizospheres of the small pumpkins (SPs). PICRUSt and FUNGuild functional prediction analyses revealed that the giant-pumpkin rhizosphere microbial community had significantly increased translation, ribosomal structure and biogenesis, nucleotide transport and metabolism, defense mechanisms, replication, recombination and repair, wood saprotroph, and undefined saprotroph levels. The above results suggest that the soil microbial compositions differed between the rhizospheres of the giant- (GP) and small-pumpkin (SP) varieties, even though the plants were grown in the same field under identical management conditions. Meanwhile, bacterial genera such as norank_f__norank_o__Elsterale, Ellin6067, norank_f__67-14, and Chujaibacter, in addition to fungal genera such as unclassified__p__Rozellomycota, unclassified__c__Chytridiomycetes, Penicillium, and unclassified__f__Chaetomiaceae, can be speculated as potential soil functional micro-organisms associated with improved pumpkin size. Full article

The red palm weevil (RPW), Rhynchophorus ferrugineus, poses a significant threat to date palms globally, heavily relying on symbiotic microbes for various physiological and behavioral functions. This comprehensive study delves into the intricate dynamics of RPW gut microbiota, revealing a diverse microbial community consisting of seven genera and eight species from Proteobacteria, Firmicutes, and Actinobacteria. The stability of gut bacteria across different life stages was observed, with notable impacts on larval metabolism attributed to shifts in bacterial composition. Bacillus subtilis emerged as a key player, producing a spectrum of metabolic enzymes. Furthermore, the gut bacteria exhibited remarkable pesticide degradation capabilities, suggesting a potential role in the host’s resistance to pesticides. The Arthrobacter sp. was identified as a promising candidate for eco-friendly pest biocontrol and biodegradation strategies. Investigating the influence of thermal stress on two groups of RPW larvae (conventional-fed and antibiotic-fed) at varying temperatures (15, 27, and 35 °C) unveiled potential survival implications. This study highlights the pivotal role of bacterial symbionts in enabling larvae adaptation and thermal stress tolerance. In essence, this research contributes crucial insights into the diversity and functions of RPW gut bacteria, emphasizing their prospective applications in pest control strategies. Full article

This research aims to study butanol fermentation from sweet sorghum stem juice (SSJ) by immobilized Clostridium beijerinckii TISTR 1461 cells on bamboo chopsticks using Arthrobacter sp. as an efficient bacterium for creating anaerobic conditions in scaled-up bioreactors. For batch culture in a 1-L screw-capped bottle, a butanol concentration (P_B), butanol productivity (Q_B), and butanol yield (Y_B/S) were 12.09 g/L, 0.26 g/L·h and 0.28 g/g, respectively. These values were ~8 to 14% higher than those of a single culture using oxygen-free nitrogen (OFN) gas to generate anaerobic conditions. When butanol fermentation by the co-culture was scaled-up to 5-L and 30-L stirred-tank fermenters, the butanol production efficiency was not different from that using the 1-L bottles. Additionally, repeated-batch butanol fermentation in the 1-L bottles by the co-culture was successfully operated for four successive cycles with high butanol production. All results clearly indicate that Arthrobacter sp. is promising for creation of anaerobic conditions for butanol production by immobilized Clostridium in large scale bioreactors. Full article

Intensive human activity in the Arctic region leads to hydrocarbon pollution of reservoirs and soils. Isolation of bacteria capable of growing at low temperatures and degrading oil and petroleum products is of scientific and practical value. The aim of this work was to study the physiology and growth in oil at temperatures below 0 °C of four strains of bacteria of the genera Pseudomonas, Rhodococcus, Arthrobacter, and Sphingomonas—previously isolated from diesel-contaminated soils of the Franz Josef Land archipelago—as well as genomic analysis of the Sphingomonas sp. AR_OL41 strain. The studied strains grew on hydrocarbons at temperatures from −1.5 °C to 35 °C in the presence of 0–8% NaCl (w/v). Growth at a negative temperature was accompanied by visual changes in the size of cells as well as a narrowing of the spectrum of utilized n-alkanes. The studied strains were psychrotolerant, degraded natural biopolymers (xylan, chitin) and n-alkanes of petroleum, and converted phosphates into a soluble form. The ability to degrade n-alkanes is rare in members of the genus Sphingomonas. To understand how the Sphingomonas sp. AR_OL41 strain has adapted to a cold, diesel-contaminated environment, its genome was sequenced and analyzed. The Illumina HiSeq 2500 platform was used for AR_OL41 genome strain sequencing. The genome analysis of the AR_OL41 strain showed the presence of genes encoding enzymes of n-alkane oxidation, pyruvate metabolism, desaturation of membrane lipids, and the formation of exopolysaccharides, confirming the adaptation of the strain to hydrocarbon pollution and low habitat temperature. Average nucleotide identity and digital DNA–DNA hybridization values for genomes of the AR_OL41 strain with that of the phylogenetically relative Sphingomonas alpine DSM 22537^T strain were 81.9% and 20.9%, respectively, which allows the AR_OL41 strain to be assigned to a new species of the genus Sphingomonas. Phenomenological observations and genomic analysis indicate the possible participation of the studied strains in the self-purification of Arctic soils from hydrocarbons and their potential for biotechnological application in bioremediation of low-temperature environments. Full article

The efficiency of plant-growth-promoting rhizobacteria (PGPR) may not be consistently maintained under field conditions due to the influence of soil microbial communities. The present study aims to investigate their impact on three PGPR-based biofertilizers in wheat. We used the PGPR Paenibacillus sp. strain B2 (PB2), PB2 in co-inoculation with Arthrobacter agilis 4042 (Mix 2), or with Arthrobacter sp. SSM-004 and Microbacterium sp. SSM-001 (Mix 3). Inoculation of PB2, Mix 2, and Mix 3 into non-sterile field soil had a positive effect on root and aboveground dry biomass, depending on the wheat cultivar. The efficiency of the PGPR was further confirmed by the protection they provided against Mycosphaerella graminicola, the causal agent of Septoria leaf blotch disease. PB2 exhibited protection of ≥37.8%, while Mix 2 showed ≥47.9% protection in the four cultivars tested. These results suggest that the interactions between PGPR and native soil microbial communities are crucial for promoting wheat growth and protection. Additionally, high-throughput sequencing of microbial communities conducted 7 days after PGPR inoculations revealed no negative effects of PB2, Mix 2, and Mix 3 on the soil microbial community structure. Interestingly, the presence of Arthrobacter spp. appeared to mitigate the potential negative effect of PB2 on bacterial community and foster root colonization by other beneficial bacterial strains. Full article

Antimicrobial peptides (AMPs) are naturally occurring molecules found in various organisms that can help to defend against invading microorganisms and reduce the likelihood of drug resistance development. This study focused on the isolation of new AMPs from the genome library of a Gram-positive bacterium called Arthrobacter sp. H5. To achieve this, we used the Bacillus subtilis expression system and employed bioinformatics techniques to optimize and modify the peptides, resulting in the development of a new synthetic antimicrobial peptide (SAMP). Ap920 is expected to be a new antimicrobial peptide with a high positive charge (+12.5). Through optimization, a new synthetic antimicrobial peptide, Ap920-WI, containing only 15 amino acids, was created. Thereafter, the antimicrobial and antifungal activities of Ap920-WI were determined using minimum inhibitory concentration (MIC) and the concentration for 50% of maximal effect (EC₅₀). The Ap920-WI peptide was observed to target the outer membrane of fungal hyphae, leading to inhibition of growth in Rhizoctonia Solani, Sclerotinia sclerotiorum, and Botrytis cinerea. In plants, Ap920-WI showed significant antifungal activity and inhibited the infestation of S. sclerotiorum on rape leaves. Importantly, Ap920-WI was found to be safe for mammalian cells since it did not show any hemolytic activity against sheep red blood cells. Overall, the study found that the new synthetic antimicrobial peptide Ap920-WI exhibits broad-spectrum activity against microorganisms and may offer a new solution for controlling plant diseases, as well as hold potential for drug development. Full article

Extremophilic microorganisms such as those that thrive in high-salt and high-alkaline environments are promising candidates for the recovery of useful biomaterials including polyhydroxyalkanoates (PHAs). PHAs are ideal alternatives to synthetic plastics because they are biodegradable, biocompatible, and environmentally friendly. This work was aimed at conducting a bioprospection of bacteria isolated from hypersaline-alkaliphilic lakes in Kenya for the potential production of PHAs. In the present study, 218 isolates were screened by Sudan Black B and Nile Red A staining. Of these isolates, 31 were positive for PHA production and were characterized using morphological, biochemical, and molecular methods. Through 16S rRNA sequencing, we found that the isolates belonged to the genera Arthrobacter spp., Bacillus spp., Exiguobacterium spp., Halomonas spp., Paracoccus spp., and Rhodobaca spp. Preliminary experiments revealed that Bacillus sp. JSM-1684023 isolated from Lake Magadi had the highest PHA accumulation ability, with an initial biomass-to-PHA conversion rate of 19.14% on a 2% glucose substrate. Under optimized fermentation conditions, MO22 had a maximum PHA concentration of 0.516 g/L from 1.99 g/L of cell dry weight and 25.9% PHA conversion, equivalent to a PHA yield of 0.02 g/g of biomass. The optimal PHA production media had an initial pH of 9.0, temperature of 35 °C, salinity of 3%, and an incubation period of 48 h with 2.5% sucrose and 0.1% peptone as carbon and nitrogen sources, respectively. This study suggests that bacteria isolated from hypersaline and alkaliphilic tropical lakes are promising candidates for the production of polyhydroxyalkanoates. Full article

Medicinal plants play an important role in the discovery of new bioactive compounds with antimicrobial activity, thanks to their pharmacological properties. However, members of their microbiota can also synthesize bioactive molecules. Among these, strains belonging to the genera Arthrobacter are commonly found associated with the plant’s microenvironments, showing plant growth-promoting (PGP) activity and bioremediation properties. However, their role as antimicrobial secondary metabolite producers has not been fully explored. The aim of this work was to characterize the Arthrobacter sp. OVS8 endophytic strain, isolated from the medicinal plant Origanum vulgare L., from molecular and phenotypic viewpoints to evaluate its adaptation and influence on the plant internal microenvironments and its potential as a producer of antibacterial volatile molecules (VOCs). Results obtained from the phenotypic and genomic characterization highlight its ability to produce volatile antimicrobials effective against multidrug-resistant (MDR) human pathogens and its putative PGP role as a producer of siderophores and degrader of organic and inorganic pollutants. The outcomes presented in this work identify Arthrobacter sp. OVS8 as an excellent starting point toward the exploitation of bacterial endophytes as antibiotics sources. Full article

A newly isolated cadmium (Cd)-resistant bacterial strain from herbicides-polluted soil in China could use atrazine as the sole carbon, nitrogen, and energy source for growth in a mineral salt medium (MSM). Based on 16S rRNA gene sequence analysis and physiochemical tests, the bacterium was identified as Arthrobacter sp. and named ST11. The biodegradation of atrazine by ST11 was investigated in experiments, with the compound present either as crystals or dissolved in di(2-ethylhexyl) phthalate (DEHP) as a non-aqueous phase liquid (NAPL). After 48 h, ST11 consumed 68% of the crystalline atrazine in MSM. After being dissolved in DEHP, the degradation ratio of atrazine was reduced to 55% under the same conditions. Obviously, the NAPL-dissolved atrazine has lower bioavailability than the crystalline atrazine. Cd²⁺ at concentrations of 0.05–1.5 mmol/L either had no effect (<0.3 mmol/L), slight effects (0.5–1.0 mmol/L), or significantly (1.5 mmol/L) inhibited the growth of ST11 in Luria-Bertani medium. Correspondingly, in the whole concentration range (0.05–1.5 mmol/L), Cd²⁺ promoted ST11 to degrade atrazine, whether crystalline or dissolved in DEHP. Refusal to adsorb Cd²⁺ may be the main mechanism of high Cd resistance in ST11 cells. These results may provide valuable insights for the microbial treatment of arable soil co-polluted by atrazine and Cd. Full article