World journal of microbiology & biotechnology最新文献

A heparinase III (NsHep-III) from Niabella sp. was identified, cloned, and expressed as soluble form in E. coli BL21 (DE3). With heparin as substrate, the maximum activity of NsHep-III of 90.0 U·mg^- 1 was achieved at pH 7.1 Tris-HCl (containing 15 mM Mg²⁺) and 30^oC. The half-life of NsHep-III was determined to be 5 h at 30^oC. The interactions between NsHep-III and substrates were studied by molecular docking. The combination of NsHep-III and a heparinase I from Bacteroides eggthii (BeHep-I) was employed to cleave heparin. Analysis of the enzymatic products of NsHep-III by SAX-HPLC showed seven different modified disaccharides, indicating that NsHep-III has a wide range of substrate specificity. The results of GPC analysis demonstrated that the average molecular weight of the product of heparin cleavage by the combination of NsHep-III/BeHep-I was reduced to 3969 Da, which accounted for 90% of all the components, and complied with the requirements of the European Pharmacopoeia. NsHep-III has notable activity and efficiency in cleaving heparin, which is potentially useful for the industrial production of low molecular weight heparin.

Contamination of water bodies is a significant global issue that results from the deliberate release of pollutants into the environment, especially from mining and metal processing industries. The main pollutants generated by these industries are metallic wastes, particularly metals, which can cause adverse effects on the environment and human health. Therefore, it is crucial to develop effective and sustainable approaches to prevent their discharge into the environment. Biofiltration is a technique used to remediate contaminated fluids using biological processes. Microorganisms and agro-industrial wastes have been used successfully as biosorbents. Hence, this review emphasizes the innovative use of agro-industrial waste reinforced with microbial biomass as bioadsorbents, highlighting their dual capacity for metal removal through various bioremediation mechanisms. The mechanisms at play in these biocomposite materials, which offer enhanced sustainability, are also analyzed. This study contributes to the advancement of knowledge by suggesting new strategies for integrating reinforced materials in biosorption processes, thus providing a novel perspective on the potential of lignocellulosic-based systems to improve decontamination efforts. On the other hand, it shows some studies where the optimization and scaling-up of biosorption processes are reported. Additionally, the implementation of multisystem approaches, leveraging multiple bioremediation techniques simultaneously, can further enhance the efficiency and sustainability of metal removal in contaminated environments.

Maternal nutritional supplementation has a profound effect on the growth and development of offspring. FAM^® is produced by co-cultivation of Lactobacillus acidophilus and Bacillus subtilis and has been demonstrated to potentially alleviate diarrhea, improve growth performance and the intestinal barrier integrity of weaned piglets. This study aimed to explore how maternal FAM improves the reproductive performance through mother-infant microbiota, colostrum and placenta. A total of 40 pregnant sows (Landrace × Large White) on d 85 of gestation with a similar parity were randomly divided into two groups (n = 20): the control group (Con, basal diet) and the FAM group (FAM, basal diet supplemented with 0.2% FAM). The experimental period was from d 85 of gestation to d 21 of lactation. The results revealed that maternal supplementation with FAM significantly decreased the number of weak-born litters and the incidence of diarrhea, as well as increasing birth weight and average weaning weight, accompanied by increased levels of colostrum nutrient composition and immunoglobulins. In addition, FAM modulated the structure of mother-infant microbiota and promoted the vertical transmission of beneficial bacteria, such as Verrucomicrobiota and Akkermansia. Furthermore, FAM contributed to improving the expression of GLU and AA transporters in the placenta, and increasing the activity of the mTOR signaling pathway. Collectively, maternal supplementation with FAM during late pregnancy and lactation could improve reproductive performance through the transmission of beneficial mother-infant microbiota and placental mTOR signaling pathway and promote fetal development.

Heavy metal and nitrogen contaminations are serious concerns in aquatic environments. Marichromatium gracile YL28, a marine purple sulfur bacterium, has shown great potential as a bioremediation agent for removing inorganic nitrogen from marine water. This study further investigated its ability to simultaneously absorb heavy metals, including Pb(II), Cu(II), Cd(II) and Cr(VI), and remove inorganic nitrogen. The contributions of photopigment and extracellular polymeric substances (EPS) in the YL28 biofilm to heavy metal adsorption and tolerance were also evaluated. The YL28 biofilm demonstrated higher adsorption efficiencies for heavy metal ions than planktonic cells. A high level of EPS was detected in the biofilm. The effects of four heavy metal on the inhibition of photopigment synthesis showed that high concentrations of Cu(II) greatly inhibited the production of BChl a and Car. The adsorption efficiencies of Pb(II), Cu(II), Cd(II), and Cr(VI) in the YL28 biofilm reactor reached 86.59%, 72.94%, 80.06%, and 95.95%, respectively. Elevated concentrations of heavy metal ions only marginally impeded ammonia nitrogen removal; they impacted neither nitrite and nitrate removals nor hindered the simultaneous elimination of three inorganic nitrogen compounds. Coupled with their ability to remove inorganic nitrogen, the high adsorption capacity and tolerance of YL28 biofilms toward heavy metal suggest a promising solution for mitigating metal pollutants.

Antibiotic resistance is a global health problem driven by the irrational use of antibiotics in different areas (such as agriculture, animal farming, and human healthcare). Sub-lethal concentrations of antibiotic residues impose selective pressure on environmental, plant-associated, and human microbiome leading to the emergence of antibiotic-resistant bacteria (ARB). This review summarizes all sources of antibiotic resistance in agricultural soils (including manure, sewage sludge, wastewater, hospitals/pharmaceutical industry, and bioinoculants). The factors (such as the physicochemical properties of soil, root exudates, concentration of antibiotic exposure, and heavy metals) that facilitate the transmission of resistance in plant microbiomes are discussed. Potential solutions for effective measures and control of antibiotic resistance in the environment are also hypothesized. Manure exhibits the highest antibiotics load, followed by hospital and municipal WW. Chlortetracycline, tetracycline, and sulfadiazine have the highest concentrations in the manure. Antibiotic resistance from organic fertilizers is transmitted to the plant microbiome via horizontal gene transfer (HGT). Plant microbiomes serve as transmission routes of ARB and ARGS to humans. The ingestion of ARB leads to human health risks (such as ineffectiveness of medication, increased morbidity, and mortality).

Type 2 Diabetes continues to be one of the major public health issues worldwide without any sustainable cure. The modulation of gut microbiota is believed to be caused by probiotic bacteria and several probiotic strains have previously shown antidiabetic activity. The present study aims to isolate potential probiotic bacteria from traditionally used fermented rice beer of Assam, India and to investigate its anti-hyperglycemic effect. Of the 20 isolated bacterial isolates, 5 isolates showed potential probiotic activities, of which, 2 isolates viz. Bacillus sp. FRB_A(A) and Acetobacter sp. FRB_B(S) showed good in vitro anti-oxidant and anti α-glucosidase activities. Based on the in vitro results, isolate Bacillus sp. FRB_A(A) was further used to evaluate the antidiabetic activity in streptozotocin induced diabetic rat model. After 21 days, the blood glucose level in diabetic rats with probiotic administration significantly lowered from 458.00 ± 46.62 mg/dl to 108.20 ± 6.76 mg/dl (p < 0.001), whereas, in diabetic rats without probiotic remained high (576.20 ± 29.48 mg/dl). On analyzing the endogenous antioxidant profile in various tissues of the experimental rats, reduced lipid peroxidation, glutathione level and superoxide dismutase and glutathione peroxidase activity were observed in probiotic administered rats in comparison to the streptozotocin treated diabetic controls. In conclusion, the bacteria Bacillus sp. FRB_A(A) isolated from fermented rice beer possesses probiotic attributes and exhibits significant anti-hyperglycemic activities.

In this study, four microalgal strains were evaluated for their biomass production capacity and macromolecule biosynthesis. These include three strains from the phylum Chlorophyta: Monoraphidium sp. LB2PC 0120, Stichococcus sp. LB2PC 0117, and Tetraselmis sp. LB2PC 0320, and one strain from the phylum Haptophyta: Isochrysis sp. LB2PC 0220. The experiments were conducted under typical laboratory-scale setups. Additionally, phylogenetic analysis based on the 18-28 S rRNA internal transcribed spacer (ITS) was performed to validate the taxonomic identity of the strains. Each strain was exposed to four different cultivation conditions based on two levels of illumination intensity [25-(LI) and 50-(HI) µmol m^- 2 s^- 1] and nitrogen loading [100-(LΝ) and 300-(HΝ) mg NaNO₃ L^- 1] in a full factorial design. All the microalgae achieved maximum biomass production under HI-HN conditions, which amounted to 1495, 919, 844, and 708 mg/L for Monoraphidium sp. LB2PC 0120, Stichococcus sp. LB2PC 0117, Tetraselmis sp. LB2PC 0320 and Isochrysis sp. LB2PC 0220, respectively, after 16 days of cultivation. Among them, Stichococcus sp. LB2PC 0117 had the highest protein content (49.9% wt.) under LI-HN conditions and Monoraphidium sp. LB2PC 0120 had the highest lipid content (44.3% wt.) under HI-LN conditions. Both Monoraphidium sp. LB2PC 0120 and Tetraselmis sp. LB2PC 0320 accumulated the highest carbohydrate content (~ 37% wt.) under LI-LN and HI-LN conditions, respectively. Based on biomass and macromolecule production, Monoraphidium sp. LB2PC 0120 was identified as the most promising candidate for upscaling studies, expecting its highly manipulatable compositional profile to support multiple applications in the food industry, rendering this microalga a valuable resource.

The association of bacteria resistant to potentially toxic metals (PTMs) with plants to remove, transfer, or stabilize these elements from the soil is an appropriate tool for phytoremediation processes in metal-contaminated environments. The objective of this study was to evaluate the potential of Rhizobium sp. LBMP-C04 for phytoremediation processes and plant growth promotion in metal-contaminated soils. Functional annotation allowed us to predict a variety of genes related to PTMs resistance and plant growth promotion in the bacterial genome. Resistance genes are mainly associated with DNA repair, and the import or export of metals in bacterial cells to maintain cell homeostasis. Genes that promote plant growth are related to mechanisms of osmotic stress tolerance, phosphate solubilization, nitrogen metabolism, biological nitrogen fixation, biofilm formation, heat shock responses, indole-3-acetic acid (IAA) biosynthesis, tryptophan, and organic acids metabolism. Biochemical tests indicated that Rhizobium sp. LBMP-C04 can solubilize calcium phosphate and produce siderophores and IAA in vitro in the presence of the PTMs Cd²⁺,Cu²⁺,Cr³⁺,Cr⁶⁺, Zn²⁺, and Ni²⁺. Results indicate the possibility of using Rhizobium sp. LBMP-C04 as a potentially efficient bacterium in phytoremediation processesin environments contaminated by PTMs and simultaneously promote plant growth.

Benzene, toluene, ethylbenzene, and xylene (BTEX) can be found in marine and estuarine waters due to accidental spills of oil and derivatives, as well as in production water and effluents discharged from petrochemical plants. Addressing the bioremediation of these compounds in saline environments and effluents with elevated salinity levels is imperative. In this study, the halotolerance of Aspergillus niger was assessed by subjecting it to a stepwise increase in salinity, achieved through progressive addition of NaCl from 2 to 30‰ (v/v). The fungal strain exhibited optimal growth support up to a salinity concentration of 25‰, accompanied by a biomass production rate of (0.93 ± 0.11) g.d^-1. The adapted biomass was employed in batch reactors to evaluate the biodegradation of BTEX (1,500 mg.L^-1). In the absence of sucrose, the reactors inoculated with fungi demonstrated almost complete BTEX removal within 7 days, with rates ranked as follows: benzene (1.12 d^-1) > toluene (0.78 d^-1) > ethylbenzene (0.65 d^-1) > xylene (0.63 d^-1). Enhanced BTEX removal rates were obtained in the presence of sucrose, notably with 2 g.L^-1: benzene (3.63 d^-1) > toluene (2.10 d^-1) > ethylbenzene (1.56 d^-1) > xylene (1.50 d^-1). Notably, benzene was found to be the sole compound adsorbed onto the fungal mycelium (1.50 ± 0.19) to (13.35 ± 4.72) mg.g^-1 of biomass.

Periodontal disease is characterized by bacterial toxins within the oral biofilm surrounding the teeth, leading to gingivitis and the gradual dissolution of the alveolar bone, which supports the teeth. Notably, symptoms in the early stages of the disease are often absent. Similarly, dental caries occurs when oral bacteria metabolize dietary sugars, producing acids that dissolve tooth enamel and dentin. These bacteria are commonly present in the oral cavity of most individuals. Metabolomics, a relatively recent addition to the "omics" research landscape, involves the comprehensive analysis of metabolites in vivo to elucidate pathological mechanisms and accelerate drug discovery. Meanwhile, the term "microbiome" refers to the collection of microorganisms within a specific environmental niche or their collective genomes. The human microbiome plays a critical role in health and disease, influencing a wide array of physiological and pathological processes. Recent advances in microbiome research have identified numerous bacteria implicated in dental caries and periodontal disease. Additionally, studies have uncovered various pathogenic factors associated with these microorganisms. This review focuses on recent findings in metabolomics and the microbiome, specifically targeting oral bacteria linked to dental caries and periodontal disease. We acknowledge the limitation of relying exclusively on the MEDLINE database via PubMed, while excluding other sources such as gray literature, conference proceedings, and clinical practice guidelines.