Acinetobacter Calcoaceticus Strain Research Articles

Calcium self-release bioremediation system combined with microbially induced calcium precipitation for the removal of ammonium nitrogen, phosphorus and heavy metals

Natural landscape water and substrate were taken to simulate the release of substrate pollutants in micropolluted water bodies, and a calcium silicate- sodium alginate (CS-SA) bioremediation system was constructed. The removal of ammonium nitrogen (NH4+-N), total nitrogen (TN) and Phosphate (PO43--P) were 99.14 %, 98.90 % and 84.44 %, respectively. The Ca2+ continuously released by CS-SA provided good microbial-induced calcium precipitation (MICP) conditions for Acinetobacter calcoaceticus strain HM12, and the removal efficiency of both Zn2+ and Cd2+ was 100 %, and the pH after remediation was consistent with that of natural water bodies. NH4+-N was removed by heterotrophic nitrification- aerobic denitrification (HN-AD) of strain HM12, and heavy metals and phosphorus were removed by co-precipitation and adsorption by MICP. High-throughput sequencing results showed that strain HM12 was effective as a bioinoculant for the remediation of the aquatic environment. The construction and operation of this bioremediation system provided a method for micropolluted water treatment and recovery of phosphorus and heavy metals.

Calcium oxalate crystals and the optimal growing conditions for Actinidia arguta

The presence, distribution, and morphology of calcium oxalate (CaC2O4, CaOx) crystals were observed in the stunted bodies of Actinidia arguta (A. arguta) vines, and their ability of microorganisms to degrade CaOx crystals was analyzed. Leaves, branches, and roots of stunted A. arguta vines were collected. In the roots, CaOx crystal bundles were distributed in the form of dotted lines. In the branches, CaOx crystal bundles were observed blocking and accumulating in the vessels. In the leaves, CaOx crystal bundles were observed in a net-like entanglement. Therefore, CaOx crystals present in the roots, branches, and leaves hinder the growth. A hydroponic cultivation with different calcium (Ca) concentrations showed that the growth of A. arguta was best at a Ca concentration of 1 cmol+/kg; at a Ca concentration of 2 cmol+/kg, the edges of the leaves began to dry out after 7 days; and at a Ca concentration of 4 cmol+/kg, the entire leaves died within 14 days. From this study, it was concluded that CaOx crystals hindered the growth of A. arguta, and the Acinetobacter calcoaceticus (A. calcoaceticus) strain was effective in degrading CaOx crystals. Therefore, the Ca concentration in the soil of the cultivation site should be managed at less than 2 cmol+/kg.

Mechanisms of ammonia, calcium and heavy metal removal from nutrient-poor water by Acinetobacter calcoaceticus strain HM12

An Acinetobacter calcoaceticus strain HM12 capable of heterotrophic nitrification-aerobic denitrification (HN-AD) under nutrient-poor conditions was isolated, with an ammonia nitrogen (NH4+-N) removal efficiency of 98.53%. It can also remove heavy metals by microbial induced calcium precipitation (MICP) with a Ca2+ removal efficiency of 75.91%. Optimal conditions for HN-AD and mineralization of the strain were determined by kinetic analysis (pH = 7, C/N = 2.0, Ca2+ = 70.0 mg L−1, NH4+-N = 5.0 mg L−1). Growth curves and nitrogen balance elucidated nitrogen degradation pathways capable of converting NH4+-N to gaseous nitrogen. The analysis of the bioprecipitation showed that Zn2+ and Cd2+ were removed by the MICP process through co-precipitation and adsorption (maximum removal efficiencies of 93.39% and 80.70%, respectively), mainly ZnCO3, CdCO3, ZnHPO4, Zn3(PO4)2 and Cd3(PO4)2. Strain HM12 produces humic and fulvic acids to counteract the toxicity of pollutants, as well as aromatic proteins to increase extracellular polymers (EPS) and promote the biomineralization process. This study provides a experimental evidence for the simultaneous removal of multiple pollutants from nutrient-poor waters.

Determination of Ochratoxin-A Detoxification and Antibiotic Resistance Potential of Acinetobacter calcoaceticus

The ochratoxin A (OTA) is a mycotoxin which is present in food products as a contaminant, and it is one of the hazardous toxins causing health risks in animals and humans. One of the main health issues is the damage to kidneys. The most adopted technique used in detoxification of this mycotoxin is biodegradation. In this study, Acinetobacter calcoaceticus isolated from soil samples was used for the detoxification of ochratoxin, and also this study explains the antibiotic resistance potential of this organism. Acinetobacter calcoaceticus was tested to see if they could break down ochratoxin A(OTA). Acinetobacter calcoaceticus was shown to be able to break down OTA among the tested microorganisms. We tested the ability of A. calcoaceticus to degrade OTA in LB medium at 25 and 28°C, with OTA concentrations of 2ppm, 6ppm, and 10ppm. A. calcoaceticus was able to break down OTA from a starting concentration of 10 (g/ml) at these conditions. At 25 and 30°C, A. calcoaceticus removed an average of 0.1005 and 0.0636 (g/ml/h of OTA, respectively, from a medium containing an initial concentration of 10 (g/ml). A. calcoaceticus degraded ochratoxin A significantly during and after the log phase of cell development at both incubation temperatures. The hypothesis is that A. calcoaceticus degraded OTA into an ochratoxin with reduced toxicity. At the same time the potential of this microorganism strain was also measured using susceptibility testing and it showed the potential of development of its resistance. Strains of Acinetobacter calcoaceticus isolated from soil samples were tested for their susceptibility against different unrelated classes of antibiotics. A. calcoaceticus was resistant to multiple antibiotics. In vitro degradation assays were used exposing the toxin to the degrading enzyme or microorganism in a controlled laboratory environment. The degradation of the toxin was monitored using various techniques such as high-performance liquid chromatography (HPLC). The significance of this study is to highlight the capability of the Acinetobacter calcoaceticus in degrading ochratoxin A, so that health risks associated with it can be reduced; also, the antibiotic resistance potential measurement helps in development of optimum antimicrobial strategy.

Interactions between Penicillium brevicompactum/Penicillium expansum and Acinetobacter calcoaceticus isolated from drinking water in biofilm development and control

Bacteria and filamentous fungi (ff) are commonly encountered in biofilms developed in drinking water (DW) distribution systems (DWDS). Despite their intimate ecological relationships, researchers tend to study bacteria and ff separately. This work assesses the impact of bacteria-ff association in biofilm formation and tolerance to chlorination. One strain of Acinetobacter calcoaceticus isolated from DW was used as a model bacterium. Penicillium brevicompactum and P. expansum isolated from DW were the ff selected. Single species and inter-kingdom adhesion and biofilm formation occurred under two shear stress (τ) conditions (0.05 and 1.6 Pa). The sessile structures were further characterized in terms of biomass production, respiratory activity and structure. The results showed that 1.6 Pa of shear stress and A. calcoaceticus-ff association favoured biofilm production. Inter-kingdom biofilms produced more biomass than A. calcoaceticus single species and reduced A. calcoaceticus susceptibility to disinfection, particularly to high sodium hypochlorite (SHC) concentrations. In addition, P. brevicompactum formed single species biofilms highly resistant to removal and inactivation by SHC. The presence of P. brevicompactum or P. expansum in inter-kingdom biofilms significantly decreased SHC removal and inactivation effects in comparison to the bacterial biofilms alone, proposing that using bacteria to form biofilms representative of DWDS can provide inaccurate conclusions, particularly in terms of biofilm production and susceptibility to disinfection.

Anthracene and Pyrene Biodegradation Performance of Marine Sponge Symbiont Bacteria Consortium.

Every petroleum-processing plant produces sewage sludge containing several types of polycyclic aromatic hydrocarbons (PAHs). The degradation of PAHs via physical, biological, and chemical methods is not yet efficient. Among biological methods, the use of marine sponge symbiont bacteria is considered an alternative and promising approach in the degradation of and reduction in PAHs. This study aimed to explore the potential performance of a consortium of sponge symbiont bacteria in degrading anthracene and pyrene. Three bacterial species (Bacillus pumilus strain GLB197, Pseudomonas stutzeri strain SLG510A3-8, and Acinetobacter calcoaceticus strain SLCDA 976) were mixed to form the consortium. The interaction between the bacterial consortium suspension and PAH components was measured at 5 day intervals for 25 days. The biodegradation performance of bacteria on PAH samples was determined on the basis of five biodegradation parameters. The analysis results showed a decrease in the concentration of anthracene (21.89%) and pyrene (7.71%), equivalent to a ratio of 3:1, followed by a decrease in the abundance of anthracene (60.30%) and pyrene (27.52%), equivalent to a ratio of 2:1. The level of pyrene degradation was lower than that of the anthracene due to fact that pyrene is more toxic and has a more stable molecular structure, which hinders its metabolism by bacterial cells. The products from the biodegradation of the two PAHs are alcohols, aldehydes, carboxylic acids, and a small proportion of aromatic hydrocarbon components.

Biodegradation mechanism of naphthalene using marine sponge symbiotic bacteria

Generally, all petroleum processing industries produce oil sludge or sludge. Polycy-clic Aromatic Hydrocarbons (PAH), one of the components contained in sludge, are hazardous and toxic waste material with toxic, carcinogenic and mutagenic properties. The research objective was to understand the biodegradation mechanism of naphthalene by utilizing a marine sponge symbiotic bacterial isolate. Partial bacteria Bacillus Sp strain AB353f (BC), sponge isolate Neopetrosia sp and Acinetobacter Calcoaceticus strain PHCDB14 (AC) isolate sponge Callyspongia (Aerizusa) as biomaterial for PAH degradation. Biodegradation method integrates bacterial suspension with 10,000 ppm naphthalene for 25 days. Every 5 days, the bio-degradation indicators were observed and the products of the destruction of naphthalene components were measured using FTIR and GC-MS. The results showed that BC isolates and AC isolates from sponge symbionts could degrade naphthalene. The biodegradation performance of BC bacteria tended to be more dominant than AC against naphthalene. Based on the functional groups resulting from FTIR, three types of biodegradation products were identified, namely: alcohol, aldehyde and carboxylic acid and one transition product in the form of a cate-chol. Maximum naphthalene bio-degradation occurs at an interaction period of 20 - 25 days.

Influence of two phosphate-potassium solubilizing bacterial species on biomass and nitrate concentration on mustard greens (Brassica juncea (L.) Czernjaew) cultivated on acid sulfate soils

Two field trials were conducted to determine the effect of P-K solubilizing bacteria and nitrogen chemical fertilizer on growth, yield and nitrate in leaf of mustard greens Brassica juncea L.) cultivated on acid sulfate soils. Eight P-K solubilizing bacterial strains composed of 3 strains of Acinetobacter calcoaceticus and 5 strains of Rhizobium sp., bacterial liquid were directly watered into plant at 3 stages [6, 12 and 21 days after planting] during vegetable cultivation, chemical fertilizer (60N – 40 P2O5 – 20 K2O) and control (no-inoculation). The study revealed that eight P-K solubilizing bacterial strains have good characteristics as nitrogen fixation, phosphate and potassium solubilisation. Application of nitrogen chemical concentration, increasing nitrate concentration of leaf of mustard greens. Application of bacterial liquid with Acinetobacter calcoaceticus strain NT4 and Acinetobacter calcoaceticus strain NT30 strain, Rhizobium tropici strain N18 and Rhizobium leguminosarum strain K35 on mustard greens cultivated on acid sulfate soils (basal fertilizer: 40 P2O5 – 20 K2O) was the best cultural practice because the this model not only supported the highest biomass, but also decreased nitrate concentration in leaf of mustard greens.

Аcinetobacter baumannii bv Tryptophandestruens bv nov. isolated from clinical samples

The aim of the study was to determine the taxonomic status of a group consisting of atypical strains of Acinetobacter baumannii, outline relevant characteristics and methods necessary for their identification. There were examined 10 strains of A. baumannii (6 of them primary comprised) bearing similar profile of atypical features isolated from clinical samples (urine, sputum) in 2017–2019 at the Military Medical Academy. Сlinical strains of typical A. baumannii (n = 36), Acinetobacter nosocomialis (n = 14), Acinetobacter pittii (n = 9) and 1 strain of Acinetobacter calcoaceticus isolated from the external environment were used in comparative studies. Atypical strains had the characteristics of A. calcoaceticus — A. baumannii (ACB) complex bacteria and were identified as A. baumannii. The utilization of substrates as the only carbon source was studied on a dense synthetic medium added with 0.2 % substrate during incubation for 72 hours at 37°C. Carbohydrate oxidation coupled to acid formation was detected on the Hugh–Leifson medium by using a micromethod. Aromatic amino acid biotransformation was carried out in liquid and dense nutrient media assessed in chromogenic reaction. The rpoB gene was used for strain genetic characterization. Amplification of two 940 and 1210 base pair (bp)-long fragments from the rpoB gene was performed by the routine polymerase chain reaction using primers with previously described sequences. Amplification products were sequenced by Sanger using Big Dye Terminator v3.1 (Applied Biosystems, USA) and capillary electrophoresis on an automatic sequencer ABI PRISM 3130 (Applied Biosystems, USA), followed by using methods for determining the similarity levels of sequenced fragments with the rpoB gene sequences of the reference strain A. baumannii ATCC 17978 (GenBank accession no. CP053098.1). It was found that all strains belonging to atypical A. baumannii spp. had a specific set of features that distinguish them from typical strains of A. baumannii as well as other types of the ACB complex: detected biotransformation of L-tryptophan (via anthranilate pathway) and anthranilic acid under unambiguous lack of such signs in other bacteria; lack of utilized sodium hippurate and L-arabinose being unambiguously evident in other bacteria; lack of utilized L-tryptophan, putrescine, L-ornithine being utilized in the majority of strains of belonging to other bacterial species. Genetic analysis showed that the control strains of typical A. baumannii displayed 99.20–99.21% similarity within the sequenced fragments of the rpoB gene with those from the rpoB gene of the reference strain. All 10 strains of atypical A. baumannii had similar features (99.20–99.21%). At the same time, parameters of control strains from other bacterial species significantly differed: A. nosocomialis (95.10–95.97%), A. pittii (94.63–94.92%), A. calcoaceticus (93.00%). Hence, the strains of atypical and typical A. baumannii are genetically homogeneous and belong to the same species. The data presented allow us to consider this group of atypical A. baumannii strains as a new biovar. We propose the name for this new biovar — tryptophandestruens (tryptophan-destroying) stemming from the Latin word destruens — destroying. Identification of A. baumannii bv. tryptophandestruens bacteria can be carried out in laboratory of any level by using tests for L-tryptophan biotransformation as well as sodium hippurate utilization.

Arrhenius Plot Analysis, Temperature Coefficient and Q10 Value Estimation for the Effect of Temperature on the Rate of Molybdenum Reduction by Acinetobacter calcoaceticus strain Dr.Y12

Molybdenum is a micronutrient that is required as a co-factor for a variety of hydroxylation and redox transfer activities in both animal and plant physiological processes. The potential of over exposure to interfere with the sperm production and egg formation processes in a number of species, including fish, is the biggest danger of excessive exposure. Only recently has it been discovered that it can be utilised as a remediation method for molybdenum-reducing bacteria. The effect of temperature on molybdenum reduction is one of the variables to consider. It is possible to use many different models to estimate the growth rate of microbes on various media based on the temperature being utilised. The Arrhenius model is popular due to the fact that it contains a limited number of parameters. In general, temperature has an effect on the development and metabolic activity of microorganisms on their substrates. Because microorganisms are so tiny, they are very sensitive to changes in their environment's temperature. Growth on molybdenum by Acinetobacter calcoaceticus strain Dr.Y12 is described, with a discontinuous chevron-like graph of apparent activation energy with a breakpoint at 32.66 oC. Regression analysis results suggest that in the lower temperature range of 20-30 oC, growth on molybdenum had an activation energy of 66.48 kJ/mol, whereas at the higher temperature range of 37–45 oC, it had an activation energy of 99.5 kJ/mol. For the examined temperature range (20-30 oC) and (37-45 oC), Q10 values of 2.46 and 3.37 and theta values of 1.09 and 1.13 were obtained, respectively. This is study is very useful in predicting the breakdown of molybdenum and the movement of molybdenum during bioremediation.

Arrhenius Plot Analysis, Temperature Coefficient and Q10 Value Estimation for the Effect of Temperature on the Rate of Molybdenum Reduction by Acinetobacter calcoaceticus strain Dr Y12

Molybdenum is a micronutrient that is required as a co-factor for a variety of hydroxylation and redox transfer activities in both animal and plant physiological processes. The potential of overexposure to interfere with the sperm production and egg formation processes in several species, including fish, is the biggest danger of excessive exposure. Only recently has it been discovered that it can be utilised as a remediation method for molybdenum-reducing bacteria. The effect of temperature on molybdenum reduction is one of the variables to consider. It is possible to use many different models to estimate the growth rate of microbes on various media based on the temperature being utilised. The Arrhenius model is popular because it contains a limited number of parameters. In general, the temperature has an effect on the development and metabolic activity of microorganisms on their substrates. Because microorganisms are so tiny, they are very sensitive to changes in their environment's temperature. Growth on molybdenum by Acinetobacter calcoaceticus strain Dr Y12 is described, with a discontinuous chevron-like graph of apparent activation energy with a breakpoint at 32.66 oC. Regression analysis results suggest that in the lower temperature range of 20-30 oC, growth on molybdenum had an activation energy of 66.48 kJ/mol, whereas, at the higher temperature range of 37–45 oC, it had an activation energy of 99.5 kJ/mol. For the examined temperature range (20-30 oC) and (37-45 oC), Q10 values of 2.46 and 3.37 and theta values of 1.09 and 1.13 were obtained, respectively. This is study is very useful in predicting the breakdown of molybdenum and the movement of molybdenum during bioremediation.

Kapasitas Bioadsorpsi Bakteri Simbiosis Spons Laut Terhadap Kontaminan Logam Berat

Heavy metal pollution in the marine environment is quite high. Arsenic and Mercury are two types of dangerous heavy metals because they are toxic and are often found as components of pollution. The research objective was to determine the bio-absorption capacity and efficiency of sponge symbiotic bacteria against arsenic and mercury contaminants. The bio-absorbent material was used by two bacterial isolates, namely Bacillus licheniformis strain ATCC 9789 (Bl.6), the sponge symbiont Auletta Sp and Acinetobacter calcoaceticus strain PHCDB14 (Ac.8), the sponge symbiont Callyspongia aerizusa. The isolates were prepared through culture, then incubated 2 x 24 hours, suspension Bl.6 and Ac.8 were made, then adapted for 24 hours. Interaction with As3 + and Hg2 + contaminants with a concentration of 100 ppm in vials with time variations 0, 4, 8, 12, 16 days. The resulting interactions are extracted, concentrated, and acidified. The bio-absorption capacity and efficiency were determined based on absorption data using Atomic Absorption Spectrometry (AAS). The average efficiency of the bio-absorption of isolate Bl.6 against As3+ = 99.95%, Hg2+ = 88.49%, while isolate Ac.8 against As3+ = 99.95% and Hg2+ = 85.73%. Based on efficiency data, capacity and bio-absorption power relative to Bl.6 = Ac.8 against As3+ and Bl.6 ≥ Ac.8 contaminants to Hg2+. Isolates Bl.6 and Ac.8 adsorbed more strongly against As3+ contaminants than Hg2+.

Cadmium and antibiotic-resistant Acinetobacter calcoaceticus strain STP14 reported from sewage treatment plant.

A bacterium designated as strain STP14 was isolated from a sewage treatment plant and identified as Acinetobacter calcoaceticus based on 16S ribosomal RNA gene sequencing. Strain STP14 exhibited resistance to several metals such as mercury, cobalt, copper, nickel, lead, and cadmium. Among these metals, the bacterium showed maximum resistance to cadmium in concentration up to 1200 mg/L. The antimicrobial susceptibility test of A. calcoaceticus strain STP14 showed coresistance to all tested antibiotics except tigecycline and chloramphenicol for which 16 ± 1- and 15 ± 1-mm zone of inhibition was observed, respectively. The protein pattern of the crude cellular extract revealed substantial differences in protein bands of untreated control and cadmium treated A. calcoaceticus strain STP14 suggesting variable protein expression under cadmium stress. Metals and antibiotic resistance are increasing phenomenon and universal concern of public health. This study improves our understanding regarding the bacterial coresistance against metals and antibiotics and the possible emergence of multidrug resistance due to selective pressure and coselection in the metal polluted sewage sludge.

Characterization and genomic analysis of a diesel-degrading bacterium, Acinetobacter calcoaceticus CA16, isolated from Canadian soil

BackgroundWith the high demand for diesel across the world, environmental decontamination from its improper usage, storage and accidental spills becomes necessary. One highly environmentally friendly and cost-effective decontamination method is to utilize diesel-degrading microbes as a means for bioremediation. Here, we present a newly isolated and identified strain of Acinetobacter calcoaceticus (‘CA16’) as a candidate for the bioremediation of diesel-contaminated areas.ResultsAcinetobacter calcoaceticus CA16 was able to survive and grow in minimal medium with diesel as the only source of carbon. We determined through metabolomics that A. calcoaceticus CA16 appears to be efficient at diesel degradation. Specifically, CA16 is able to degrade 82 to 92% of aliphatic alkane hydrocarbons (CnHn + 2; where n = 12–18) in 28 days. Several diesel-degrading genes (such as alkM and xcpR) that are present in other microbes were also found to be activated in CA16.ConclusionsThe results presented here suggest that Acinetobacter strain CA16 has good potential in the bioremediation of diesel-polluted environments.

Characterization of the copper resistance mechanism and bioremediation potential of an Acinetobacter calcoaceticus strain isolated from copper mine sludge.

Bioremediation is one of the most effective ways for removal of heavy metals and restoration of contaminated sites. This study investigated the copper (Cu) resistance mechanism and bioremediation potential of an Acinetobacter calcoaceticus strain KW3 isolated from sludge of Cu mine. The effect of Cu concentrations on the bacterial growth, biomass, and adsorption capacity, as well as the effect of contact time on the adsorption process was evaluated in a batch biosorption test. The strain exhibited strong tolerance of Cu, and the minimal inhibitory concentration was around 400mgCu2+L-1, at which the maximum adsorption capacity was 14.1mgg-1 dry cell mass. Cell walls and intracellular soluble components adsorbed 51.2% and 46.6% of Cu2+, respectively, suggesting that the strain not only adsorbed Cu2+ on the surface but also metastasized ions into cells. The adsorption and kinetic data were well fitted with Freundlich isotherm and Pseudo-second-order models, suggesting that cell surface had a high affinity for Cu2+ and the chemisorption could be the main adsorption mechanism. Scanning electron microscope and Fourier transform infrared spectroscopy analysis revealed that hydroxyl, carboxylic, amide, sulfate, and phosphate on cell walls might be involved in the biosorption process. Two-dimensional gel electrophoresis and MALDI-TOF/TOF mass spectrometry revealed that some oxidoreductases, in particular Cu resistance protein A (CopA) expression levels, were upregulated. Antioxidant defense and P1B-type ATPases CopA efflux might play a crucial role in maintaining cellular homeostasis and intracellular detoxification. To our knowledge, this is the first time that Cu resistance mechanisms, especially intracellular enzymatic mechanisms, were identified in an A. calcoaceticus KW3 strain.

Screening and sensitivity of non-lactose fermenting bacteria to antibiotics by Vitek-2 compact system

We are collected 150 clinical sample from different private veterinary clinics in Basrah province . Included 25 isolates from nasal discharge, 45 from feces , 35 from pus/wound infections, 20 from blood and 25 from ear swab .All isolates were subjected to microscopic examination and diagnosed 4 species of Non- Fermenting Gram Negative Bacilli (NFGNB) bacteria based on 47 biochemical tests by Vitek 2 a compact system where the species were 48 strain (32%) of Pseudomonas aeruginosa , 32 strain (21.33%) of Burkholderia cepacia, 31strain (20.66%) of Sphingomonas paucimobilis, 20 strain (13.33%) of Proteus mirabilis and 19 strain (12.66%) of Acinetobacter calcoaceticus . NFGNB results showed antibiotic susceptibility to different antibiotic resistance and susceptibility, where isolates showed Pseudomonas aeruginosa, Burkholderia cepacia and Proteus mirabilis were susceptibility to antibiotic Meropenem (80% -98%), while Acinetobacter spp, Pseudomonas aeruginosa least susceptible to Cefuroxime and Trimethoprim/Sulfamethoxazole (20% – 30%). The bacteria showed Sphingomonas paucimobilis showed resistance to all the antibiotics tested. The current study was carried out with the aim of diagnosing and identifying NFGNB isolated from clinical samples and evaluating their clinical importance and study of antibiotic resistance.

Ecological role of Acinetobacter calcoaceticus GSN3 in natural biofilm formation and its advantages in bioremediation

This study assessed the role of a new Acinetobacter calcoaceticus strain, GSN3, with biofilm-forming and phenol-degrading abilities. Three biofilm reactors were spiked with activated sludge (R1), green fluorescent plasmid (GFP) tagged GSN3 (R2), and their combination (R3). More than 99% phenol removal was achieved during four weeks in R3 while this efficiency was reached after two and four further operational weeks in R2 and R1, respectively. Confocal scanning electron microscopy revealed that GSN3-gfp strains appeared mostly in the deeper layers of the biofilm in R3. After four weeks, almost 7.07 × 107 more attached sludge cells were counted per carrier in R3 in comparison to R1. Additionally, the higher numbers of GSN3-gfp in R2 were unable to increase the efficiency as much as measured in R3. The presence of GSN3-gfp in R3 conveyed advantages, including enhancement of cell immobilization, population diversity, metabolic cooperation and ultimately treatment efficiency.

Production of microbial biomass feedstock via co-cultivation of microalgae-bacteria consortium coupled with effective wastewater treatment: A sustainable approach

A sustainable process was demonstrated towards production of biomass feedstock coupled with wastewater treatment. Sustainability was endeavored to be achieved via symbiotic growth of microalgae and bacteria coupled with utilization of wastewater as cheap source of nutrient and water. The best microalgae-bacteria consortium comprised of two microalgae Chlorella sorokiniana strain DBWC2 &Chlorella sp. strain DBWC7 and two bacteria Klebsiella pneumoniae strain ORWB1 &Acinetobacter calcoaceticus strain ORWB3. When the consortium was characterized on artificial wastewater and raw dairy wastewater, a significant improvement in the microalgal growth, total biomass titer, chemical oxygen demand (COD), and nitrate removal efficiency was observed as compared to microalgae alone. Total biomass titer, nitrate removal, COD removal efficiency was found to be 2.84 g L−1, 93.59%, 82.27% and 2.87 g L−1, 84.69%, 90.49% in artificial wastewater and raw dairy wastewater respectively. The selected microalgae-bacteria consortium may be a potential platform towards sustainable production of microbial biomass using wastewater.

The H2-oxidizing Rhizobacteria Associated with Field-Grown Lentil Promote the Growth of Lentil Inoculated with Hup+ Rhizobium Through Multiple Modes of Action

Certain H2-oxidizing rhizobacteria promote the growth of legume plants nodulated with rhizobia devoid of an uptake hydrogenase system (Hup−). We demonstrated and assessed the plant growth-promoting ability of H2-oxidizing rhizobacteria naturally associating with lentil roots nodulated by rhizobia possessing an uptake hydrogenase system (Hup+ lentil) in semiarid Canada. The ten H2-oxidizing rhizobacteria isolated were strains of Variovorax paradoxus, Variovorax sp., Rhodococcus sp., Mycobacterium sp., Acinetobacter sp., Acinetobacter calcoaceticus, and Curtobacterium sp. Several of these strains increased Hup+ lentil shoot and root biomasses, and root nodule number in the absence or presence of drought stress. Inoculation with H2-oxidizing rhizobacteria enhanced the growth of Hup+ lentil infected by the fungal root pathogens Fusarium avenaceum, Rhizoctonia solani, and Pythium ultimum. Fusarium avenaceum growth was markedly suppressed by all H2-oxidizing rhizobacteria in vitro, and seven isolates also suppressed the growth of both R. solani and P. ultimum. Siderophore production was detected in nine isolates and one isolate could solubilize phosphate. Indole-3-acetic acid production was found in four isolates, and 1-aminocyclopropane-1-carboxylate deaminase activity in six isolates. Most H2-oxidizing rhizobacterial isolates exhibited multiple plant growth-promoting attributes and all isolates exhibited at least one. Our results suggest that the H2-oxidizing rhizobacteria naturally associating with lentil roots in semiarid Canada are beneficial in an Hup+ environment.

The whole genome sequencing of Acinetobacter-calcoaceticus-baumannii complex strains involved in suspected outbreak in an Intensive Care Unit of a pediatric hospital

Background: To analyze the genetic characteristics of Acinetobacter-calcoaceticus-baumannii complex strains isolated in suspected outbreak in a Intensive Care Unit of a pediatric hospital in order to promptly stop the dissemination of this dangerous strain.Methods: This study described the use of whole genome obtained by Next Generation Sequencing to define the clonality of 13 Acinetobacter-calcoaceticus-baumannii complex strains and to study their Resistoma. This was required because Acinetobacter baumannii is known to be resistant to desiccation and to disinfectants and is difficult to treat and eradicate. Thus, this microorganism is a major problem that demands a rigorous outbreak monitoring program to prevent and control the spread of the dangerous strain.Results: The first result of our analysis has been to describe precisely the characteristics of isolates involved in the nosocomial infection, reduce the dimension of the more problematic isolates sustaining the outbreak and promptly facilitate the control of the strains diffusion. Indeed, our study indicated that among the 13 Acinetobacter baumannii-calcoacteticus complex strains, identified by biochemical and mass-spectrometry assays, 7 were Acinetobacter baumannii, 5 were Acinetobacter calcoaceticus, and one was Acinetobacter haemolyticus. The analysis of clonality of Acinetobacter baumannii indicated that three strains of ST744 were identical for > 99.8% among them and thus have sustained an outbreak in Intensive Care Unit. All personnel and possible environment samples were also monitored and all the procedures aimed to the prevention and control of Hospital Acquired Infections (HAI), have been strictly enforced by the Hospital Infection Control Committee. This gave the possibility to trace a strain from an environmental contamination characterized by high degree of clonality with the one isolated from a patient. On the contrary Acinetobacter calcoaceticus strains were different from each other and thus they were not responsible for any outbreak. The Resistoma analysis indicated a correspondence between phenotypic and genotypic characteristics of analyzed strains.Conclusions: Next Generation Sequencing is an appropriate technique to trace the circulation of dangerous strains sustaining nosocomial infections. The combination of the high resolution genotyping together with the definition of the antibiotic genetic determinants and the precise species identification make this technique a useful tool employed as standard practice to control HAI.