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Applied Microbiology and Biotechnology Aug 2023While the in situ return of corn straw can improve soil fertility and farmland ecology, additional bacterial agents are required in low-temperature areas of northern...
While the in situ return of corn straw can improve soil fertility and farmland ecology, additional bacterial agents are required in low-temperature areas of northern China to accelerate straw degradation. Moisture is an important factor affecting microbial activity; however, owing to a lack of bacterial agents adapted to low-temperature complex soil environments, the effects of soil moisture on the interaction between exogenous bacterial agents and indigenous soil microorganisms remain unclear. To this end, we explored the effect of the compound bacterial agent CFF constructed using Pseudomonas putida and Acinetobacter lwoffii, developed to degrade corn straw in low-temperature soils (15 °C), on indigenous bacterial and fungal communities under dry (10% moisture content), slightly wet (20%), and wet (30%) soil-moisture conditions. The results showed that CFF application significantly affected the α-diversity of bacterial communities and changed both bacterial and fungal community structures, enhancing the correlation between microbial communities and soil-moisture content. CFF application also changed the network structure and the species of key microbial taxa, promoting more linkages among microbial genera. Notably, with an increase in soil moisture, CFF enhanced the rate of corn straw degradation by inducing positive interactions between bacterial and fungal genera and enriching straw degradation-related microbial taxa. Overall, our study demonstrates the alteration of indigenous microbial communities using bacterial agents (CFF) to overcome the limitations of indigenous microorganisms for in situ straw-return agriculture in low-temperature areas. KEY POINTS: • Low-temperature and variable moisture conditions (10-30%) were compared • Soil microbial network structure and linkages between genera were altered • CFF improves straw degradation via positive interactions between soil microbes.
Topics: Zea mays; Temperature; Soil Microbiology; Agriculture; Soil; Bacteria
PubMed: 37392246
DOI: 10.1007/s00253-023-12644-8 -
Microorganisms Aug 2023is a Gram-negative facultative anaerobic bacillus identified from water sources and later from food (onions, cream, unpasteurized milk, and Spanish pork sausages),...
is a Gram-negative facultative anaerobic bacillus identified from water sources and later from food (onions, cream, unpasteurized milk, and Spanish pork sausages), which, under certain circumstances, can cause infections in humans, especially in immunocompromised patients. Few cases of human infections have been reported in the literature, such as endophthalmitis, urinary tract infection, pyonephrosis, and sepsis. We describe the case of a 69-year-old Caucasian male patient who lives in an urban environment and presents himself to the emergency department with chills, fever, myalgias, marked physical asthenia, dry cough, dyspnea, symptoms for which he is tested and confirmed with SARS-CoV-2 infection using real-time reverse transcriptase-polymerase chain reaction (RT-PCR) from nasal and pharyngeal swabs, after being admitted the same day (25 May 2023) to the Infectious Diseases Clinic from the County Clinical Emergency Hospital Sibiu, Romania. At the time of admission, a pulmonary computerized tomography (CT) scan was performed, which revealed a severity score of 10 out of 25. In the second week of the disease, the patient presents with hemoptysis, from which bacteriological examinations are carried out, and and are identified. The evolution was slowly favorable under antiviral treatment, corticotherapy, antibiotic therapy (in the absence of the identified etiology, initially meropenem was administered in association with linezolid, and then ceftazidime-avibactam), voriconazole, anakinra, salbutamol inhaler, inhalation corticosteroids, with slow reduction in oxygen requirement, the patient continued oxygen therapy at home after discharge with a flow rate of 5 L/minute. During the third harvesting of sputum samples, was isolated along with , both strains of low-virulence species, and maintained susceptibility to antibiotics. In the context of an immunosuppressed patient with previous pulmonary surgery for actinomycosis, chronic obstructive pulmonary disease, and bronchiectasis, all these conditions are favorable for biofilm formation. remains a pathogen rarely isolated in human pathology, but we should pay more attention, especially in the immunosuppressed patient, where it can be responsible for an extremely serious clinical picture.
PubMed: 37763987
DOI: 10.3390/microorganisms11092143 -
MethodsX Dec 2023Polyhydroxyalkanoate (PHA)-producing bacteria represent a powerful synthetic biology chassis for waste bioconversion and bio-upcycling where PHAs can be produced as the...
Polyhydroxyalkanoate (PHA)-producing bacteria represent a powerful synthetic biology chassis for waste bioconversion and bio-upcycling where PHAs can be produced as the final products. In this study, we present a seamless plasmid construction for orthogonal expression of recombinant PET hydrolase (PETase) in model PHA-producing bacteria and . To this end, this study described seamless cloning and expression methods utilizing SureVector (SV) system for generating pSV-Ortho-PHA (pSVOP) expression platform in bioengineered and . Genetic parts specifically Trc promoter, pBBR1 origin of replication, anchoring proteins and signal sequences were utilized for the transformation of pSVOP-based plasmid in electrocompetent cells and orthogonal expression of PETase in both and . Validation steps in confirming functional expression of PETase activity in corresponding PETase-expressing strains were also described to demonstrate seamless and detailed methods in establishing bioengineered and as whole-cell biocatalysts tailored for plastic bio-upcycling.•Seamless plasmid construction for orthogonal expression in PHA-producing bacteria.•Step-by-step guide for high-efficiency generation of electrotransformants of and •Adaptable methods for rapid strain development (Design, Build, Test and Learn) for whole-cell biocatalysis.
PubMed: 37846354
DOI: 10.1016/j.mex.2023.102434 -
Cell Reports Sep 2023Maximizing the production of heterologous biomolecules is a complex problem that can be addressed with a systems-level understanding of cellular metabolism and...
Maximizing the production of heterologous biomolecules is a complex problem that can be addressed with a systems-level understanding of cellular metabolism and regulation. Specifically, growth-coupling approaches can increase product titers and yields and also enhance production rates. However, implementing these methods for non-canonical carbon streams is challenging due to gaps in metabolic models. Over four design-build-test-learn cycles, we rewire Pseudomonas putida KT2440 for growth-coupled production of indigoidine from para-coumarate. We explore 4,114 potential growth-coupling solutions and refine one design through laboratory evolution and ensemble data-driven methods. The final growth-coupled strain produces 7.3 g/L indigoidine at 77% maximum theoretical yield in para-coumarate minimal medium. The iterative use of growth-coupling designs and functional genomics with experimental validation was highly effective and agnostic to specific hosts, carbon streams, and final products and thus generalizable across many systems.
PubMed: 37665664
DOI: 10.1016/j.celrep.2023.113087 -
Journal of Environmental Sciences... Mar 2024Arsenic is a ubiquitous environmental pollutant. Microbe-mediated arsenic bio-transformations significantly influence arsenic mobility and toxicity. Arsenic...
Arsenic is a ubiquitous environmental pollutant. Microbe-mediated arsenic bio-transformations significantly influence arsenic mobility and toxicity. Arsenic transformations by soil and aquatic organisms have been well documented, while little is known regarding effects due to endophytic bacteria. An endophyte Pseudomonas putida ARS1 was isolated from rice grown in arsenic contaminated soil. P. putida ARS1 shows high tolerance to arsenite (As(III)) and arsenate (As(V)), and exhibits efficient As(V) reduction and As(III) efflux activities. When exposed to 0.6 mg/L As(V), As(V) in the medium was completely converted to As(III) by P. putida ARS1 within 4 hr. Genome sequencing showed that P. putida ARS1 has two chromosomal arsenic resistance gene clusters (arsRCBH) that contribute to efficient As(V) reduction and As(III) efflux, and result in high resistance to arsenicals. Wolffia globosa is a strong arsenic accumulator with high potential for arsenic phytoremediation, which takes up As(III) more efficiently than As(V). Co-culture of P. putida ARS1 and W. globosa enhanced arsenic accumulation in W. globosa by 69%, and resulted in 91% removal of arsenic (at initial concentration of 0.6 mg/L As(V)) from water within 3 days. This study provides a promising strategy for in situ arsenic phytoremediation through the cooperation of plant and endophytic bacterium.
Topics: Arsenates; Arsenic; Pseudomonas putida; Biodegradation, Environmental; Soil
PubMed: 37980011
DOI: 10.1016/j.jes.2023.02.020 -
3 Biotech Dec 2023The present study was carried out to assess the growth-promoting ability of non-rhizobial endophytes in groundnut (). Thirteen endophytic bacteria with different...
The present study was carried out to assess the growth-promoting ability of non-rhizobial endophytes in groundnut (). Thirteen endophytic bacteria with different morphologies were isolated from the root and nodules of groundnut. These isolates significantly enhanced the growth of groundnut in sterilised vermiculite, though the isolates were unable to nodulate the host plant. The endophytic nature of these isolates was confirmed by their re-isolation from the sterilised and macerated roots of the plants. The isolates exhibited in vitro tricalcium phosphate and zinc solubilization, production of siderophores, auxins and ammonia as well as growth on different nitrogen-free media. The phosphate solubilization and auxin production varied from 50 to 196 and 17 to 71 µg/ml, respectively by the isolates. Based on phenotypic tests and 16S rRNA gene sequencing, four potential strains were identified as sp. R3, R6, GRE5 and GRE6. A significant increase in plant growth, chlorophyll content, nodule count and shoot nutrient content of groundnut was observed with these bacterial inoculations over the uninoculated control in greenhouse. The bacterial treatments resulted in increased N, P and K content in the shoot up to 87, 96 and 44%, respectively, over the control. Physico-chemical properties and available nutrient content of soil were also improved on bacterial inoculations. The results indicated that groundnut harbours beneficial non-rhizobial bacterial endophytes with the potential to be used as microbial inoculants in groundnut. as a non-nodulating nodule endophyte of groundnut is reported for the first time.
PubMed: 38037659
DOI: 10.1007/s13205-023-03837-z -
Microbial Biotechnology Mar 2024Medium-chain-length α,ω-diols (mcl-diols) play an important role in polymer production, traditionally depending on energy-intensive chemical processes. Microbial cell...
Medium-chain-length α,ω-diols (mcl-diols) play an important role in polymer production, traditionally depending on energy-intensive chemical processes. Microbial cell factories offer an alternative, but conventional strains like Escherichia coli and Saccharomyces cerevisiae face challenges in mcl-diol production due to the toxicity of intermediates such as alcohols and acids. Metabolic engineering and synthetic biology enable the engineering of non-model strains for such purposes with P. putida emerging as a promising microbial platform. This study reviews the advancement in diol production using P. putida and proposes a four-module approach for the sustainable production of diols. Despite progress, challenges persist, and this study discusses current obstacles and future opportunities for leveraging P. putida as a microbial cell factory for mcl-diol production. Furthermore, this study highlights the potential of using P. putida as an efficient chassis for diol synthesis.
Topics: Pseudomonas putida; Polyhydroxyalkanoates; Metabolic Engineering; Escherichia coli; Synthetic Biology
PubMed: 38528784
DOI: 10.1111/1751-7915.14423 -
Biotechnology and Bioengineering Jul 2023Biofilms can increase pathogenic contamination of drinking water, cause biofilm-related diseases, alter the sediment erosion rate, and degrade contaminants in...
Biofilms can increase pathogenic contamination of drinking water, cause biofilm-related diseases, alter the sediment erosion rate, and degrade contaminants in wastewater. Compared with mature biofilms, biofilms in the early-stage have been shown to be more susceptible to antimicrobials and easier to remove. Mechanistic understanding of physical factors controlling early-stage biofilm growth is critical to predict and control biofilm development, yet such understanding is currently incomplete. Here, we reveal the impacts of hydrodynamic conditions and microscale surface roughness on the development of early-stage Pseudomonas putida biofilm through a combination of microfluidic experiments, numerical simulations, and fluid mechanics theories. We demonstrate that early-stage biofilm growth is suppressed under high flow conditions and that the local velocity for early-stage P. putida biofilms (growth time < 14 h) to develop is about 50 μm/s, which is similar to P. putida's swimming speed. We further illustrate that microscale surface roughness promotes the growth of early-stage biofilms by increasing the area of the low-flow region. Furthermore, we show that the critical average shear stress, above which early-stage biofilms cease to form, is 0.9 Pa for rough surfaces, three times as large as the value for flat or smooth surfaces (0.3 Pa). The important control of flow conditions and microscale surface roughness on early-stage biofilm development, characterized in this study, will facilitate future predictions and managements of early-stage P. putida biofilm development on the surfaces of drinking water pipelines, bioreactors, and sediments in aquatic environments.
Topics: Pseudomonas putida; Hydrodynamics; Drinking Water; Biofilms; Bioreactors
PubMed: 37102364
DOI: 10.1002/bit.28409 -
Heliyon Nov 2023In this work, it is presented a first approach of a mathematical and kinetic analysis for improving the decoloration and further degradation process of an azo dye named...
In this work, it is presented a first approach of a mathematical and kinetic analysis for improving the decoloration and further degradation process of an azo dye named acid red 27 (AR27), by means of a novel microbial consortium formed by the fungus and the bacterium . A multivariate analysis was carried out by simulating scenarios with different operating conditions and developing a specific mathematical model based on kinetic equations describing all stages of the biological process, from microbial growth and substrate consuming to decoloration and degradation of intermediate compounds. Additionally, a sensitivity analysis was performed by using a factorial design and the Response Surface Method (RSM), for determining individual and interactive effects of variables like, initial glucose concentration, initial dye concentration and the moment in time for bacterial inoculation, on response variables assessed in terms of the minimum time for: full decoloration of AR27 (R = 2.375 days); maximum production of aromatic metabolites (R = 1.575 days); and full depletion of aromatic metabolites (R = 12.9 days). Using RSM the following conditions improved the biological process, being: an initial glucose concentration of 20 g l, an initial AR27 concentration of 0.2 g l and an inoculation moment in time of at day 1. The mathematical model is a feasible tool for describing AR27 decoloration and its further degradation by the microbial consortium of and , this model will also work as a mathematical basis for designing novel bio-reaction systems than can operate with the same principle of the described consortium.
PubMed: 38027625
DOI: 10.1016/j.heliyon.2023.e21793 -
Toxics Jul 2023The biodegradation of paraquat was investigated using immobilized microbial cells on nanoceramics fabricated from nanoscale kaolinite. and , which degrade paraquat,...
The biodegradation of paraquat was investigated using immobilized microbial cells on nanoceramics fabricated from nanoscale kaolinite. and , which degrade paraquat, were immobilized separately on nanoceramics (respectively called IC-P and IC-B). The attachment of bacteria to nanoceramics resulted from electrostatic force interactions, hydrogen bonding, and covalent bonding (between the cells and the support materials). The initial 10 mg L concentration of paraquat in water was removed by the adsorption process using nanoceramics at 68% and ceramics at 52%, respectively. The immobilized cells on the nanoceramics were able to remove approximately 92% of the paraquat within 10 h, whereas the free cells could only remove 4%. When the paraquat was removed, the cell-immobilized nanoceramics exhibited a significant decrease in dissolved organic nitrogen (DON). IC-B was responsible for 34% of DON biodegradation, while IC-P was responsible for 22%. Ammonia was identified as the end product of ammonification resulting from paraquat mineralization.
PubMed: 37505603
DOI: 10.3390/toxics11070638