Enterobacter Aerogenes Strain Research Articles

Isolation and Characterization of a Molybdenum-reducing Enterobacter aerogenes strain Amr-18 in Soils from Egypt that Could Grow on Amides

In the foreseeable future, bioremediation is by far the most cost-effective method for removing noxious chemical toxins and organic contaminants, especially at low concentrations when other methods like physical or chemical procedures wouldn't be successful. For the objective of bioremediation, we have isolated a molybdenum-reducing bacteria from agricultural soil. The ideal pH and temperature ranges for the bacterium to reduce molybdate to molybdenum blue (Mo-blue) are 6.3 and 6.8, respectively. The best electron donor for molybdate reduction was glucose, which was followed in descending order by sucrose, lactose, l-rhamnose, d-mannose, raffinose, d-adonitol, maltose, d-mannitol, melibiose, cellobiose, glycerol, and d-sorbitol. Phosphate concentrations of 7.5 mM and molybdate concentrations of 15 – 20 mM are also necessary. The Mo-blue that was formed had an absorption spectrum that was comparable to that of earlier Mo-reducing bacteria and closely resembled that of reduced phosphomolybdate. At 2 ppm, copper (II), mercury (I), and silver I hindered molybdenum reduction by 80.2, 74.8, and 30.4%, respectively. The bacterium was tentatively identified as Enterobacter aerogenes strain Amr-18 after phenotypic and biochemical identifications. The bacterium could thrive on the amides, acrylamide, acetamide, and propionamide and could use acrylamide as an electron donor for molybdenum reduction. This bacterium has a highly valued trait that makes it useful for bioremediation: the capacity to detoxify a variety of toxicants.

Elucidation of antibacterial activity of Bacillus sp. and Alcaligenes sp. metabolites against multidrug-resistant bacteria

Different resistance mechanisms are involved in exhibiting resistance to different groups of antibiotics. Researchers are searching for new therapeutic options to encounter the emerging trend of microbial resistance. Bacteria were isolated from the extreme environment of Cholistan Desert and were screened for characterization. Potential metabolites that showed broad-spectrum activity were partially purified using silica gel chromatography and determined their minimum inhibitory concentration. A collection of 50 bacterial isolates from soil samples was screened for metabolite production and among them isolate R19 of Bacillus sp. and isolate A8 of Alcaligenes sp. had high similarity with strong antimicrobial metabolite producers. The growth of A8 was stable at slight acidic pH while R19 was best at neutral pH. Similarly, the best growth of A8 was observed at 37 °C while R19 at 35 °C. Minimum inhibitory concentration of purified compounds of Bacillus sp. were determined at concentration range of (3.12 – 100 %) against multidrug-resistant (MDR) strains of Shigella, Enterobacter aerogenes, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Klebsiella pneumonia and produced 10 – 25 mm zone of inhibition. Metabolites of Alcaligenes sp. were sufficient to inhibit the growth of all selected MDR bacteria at concentrations 12.25 – 100 % and shows 10 – 20 mm zone of inhibition. Bacillus sp. and Alcaligenes sp. can be used as producers of potential antibacterial metabolites. Proper utilization of selected metabolites can be helpful in combating emerging drug resistant pathogenic bacteria. In addition, further proteomic analysis and structural insight should be considered to elaborate their active ingredients and its efficacy.

Molecular characterization of Enterobacter aerogenes isolated from urinary tract infections in Iran

The prevalence of multidrug-resistant Enterobacter aerogenes strains in UTIs is increasing. Therefore, the purpose of this study was to examine the mechanisms of resistance in Enterobacter aerogenes strains isolated from the urinary tract of infected patients. To achieve this goal, 786 urine samples from Shahrekord, Iran, were collected from June 2019 to February 2020. After isolating and identifying E. aerogenes samples, antibiotic susceptibility testing was done on the strains using Kirby-Bauer's disk diffusion method. The biofilm formation assays were performed to study the link between antibiotic resistance and biofilm formation and virulence genes. As a result, amongst the 786 urine samples, 50 strains were identified as E. aerogenes. The lowest rate of resistance was observed with imipenem (30%). This study also reports that all the strains of E. aerogenes are biofilm producers, with 50% of isolates producing a large amount, 30% a moderate amount, and 20% a small amount of biofilm. 42% were identified in the phenotypic study of ESBLs. In the PCR test, (64%) produced broad-spectrum beta-lactamases. Prevalence of qnrC, qnrB, qnrA, tetA, tet B, acc(3)IIa, acc(2)IIa, ant(2)Ia and Sul1 in strong producing isolates reported 100%, 80.95%,% 58.14, 87.5%, 81.58%, 86.67%, 82.14, 81.48% and 90% respectively. In the statistical analysis based on the chi-square test, a statistically significant relationship was reported between qnrA, qnrB, tetA, tetB, Sul1, ant(2)Ia, ant(3)I, aac(3)II, and biofilm formation. Resistance to cephalothin, ceftriaxone, cefotaxime and ceftazidime were reported 40%, 34%, 30% and 30%, respectively. Out of 50 Enterobacter aerogenes, 32 isolates (64%) were identified in the phenotypic study of ESBLS, prevalence of blaCTX−M, blaTEM and blaSHV reported 30%, 20% and 14% respectively. There is a significant relationship between resistance to ceftriaxone and blaCTX−M. Prevalence of csgA, ybtS, markD, rmpA, csgD and fimH in strong biofilm formation isolates reported 84%, 83.33%, 80%, 80%, 80% and 66% respectively. The chi-square test showed a statistically significant relationship between biofilm production and resistance genes fimH, csgA, csgD, ybtS, and mrkD. The findings of this study indicate that the ability to produce biofilms is associated with the increase of antibiotic resistance and virulence genes. These agents enable bacteria to produce biofilms that ultimately lead to colonization and bacterial survival in the body.

A novel L‐asparaginase from the symbiotic Enterobacter aerogenes isolated from Eucheuma sp.

This study was aimed to purify and characterize the enzyme L-asparaginase from endophytic microorganisms of Eucheuma sp. in Puntondo Island, South Sulawesi, Indonesia. Research stages were ammonium sulfate precipitation, dialysis, and Sephadex G-75 gel filtration chromatography and Sephadex CMC-50 ion-exchange chromatography matrices. The result of test activities of ammonium sulfate fraction showed the highest range of 40%–60% the activity value of 6.71 IU/ml. The highest protein content was obtained on a 0%–20% fraction of 2.76 mg/ml. Temperature and pH assessments indicated that L-asparaginase had optimum activity at 37°C and pH 8, respectively. At the stage of dialysis, the highest protein content was 5.17 IU/ml in a 0%–20% fraction, and the highest enzyme activity was 1.23 IU/ml in a 20%–40% fraction. The results of gel filtration chromatography fractions G-75 were F5–F10, with a specific activity of 0.60 U/mg, 2.05 times higher purity level than the crude extract enzyme. The results of CMC-50 ion-exchange chromatography showed that F54 and F55 fractions had a specific activity of 106.97 and 295.38 U/mg, respectively, with a purity level of 366.34 and 1,011.57 times higher than the crude extract enzyme. Novelty impact statement Enterobacter aerogenes strain P5, an endophytic bacterium from Eucheuma sp., can produce pure L-asparaginase enzyme with a high specific activity applied in pharmaceuticals nutraceutical applications.

1069. In Vitro Activity of Tebipenem Against Clinically Significant Gram-Negative Bacteria Isolated from Patients with Cancer

Abstract Background Gram negative (GN) bacterial infections are on the rise in patients with cancer and frequently require extended hospital stays that may lead to a major increase in healthcare cost. This study aimed to evaluate the in vitro activity of a novel oral carbapenem, tebipenem against recent gram-negative clinical isolates from our cancer patients. Methods All 173 clinical isolates from our cancer patients including 36 Extended Spectrum Beta-Lactamase (ESBL) isolates from blood cultures were tested against tebipenem and other comparators. Clinical and Laboratory Standards Institute (CLSI) approved broth microdilution method was used. Appropriate ATCC controls were included. MIC50, MIC90, MIC ranges and percent of susceptibility calculations ware made using FDA breakpoints when available. The tebipenem provisional susceptibility breakpoint for most GN organism is ≤ 0.125 mg/L. Results Tebipenem and comparators antibiotics susceptibility percent (S: %), and MIC90 are shown in the table below. Tebipenem demonstrated highly potent activity against Escherichia coli, Klebsiella pneumoniae (including ESBL producing strains), Enterobacter cloacae and inhibited 90% of the Enterobacter aerogenes strains screened. MIC90s ranged from 0.06-0.25 mg/L for all tested Enterobacteriaceae. At a provisional breakpoints of 0.125 mg/L, the susceptibilities, MICs and ranges were comparable to meropenem, and ertapenem. Comparative study between Tebipenem and comparators for MIC90 (mg/L.) and Susceptibility (%) results against Gram-Negative Bacteria Isolated from Patients with Cancer Conclusion Our data demonstrate that oral tebipenem has promising activity against clinically significant bacterial pathogens isolated from cancer patients, and it has similar activity to that of other tested carbapenem. Further clinical evaluation for oral carbapenem treatment of bacterial infections is warranted. Disclosures All Authors: No reported disclosures

Identification of Entomopathogenic Nematode-Associated Bacteria Originating from Mojokerto

Entomopathogenic nematodes (EPN) are one of the soil worms that have been widely used as a natural pest control. EPN has its pathogenic capability because of the mutualistic interactions between nematodes and symbiotic bacteria inside the digestive tract of nematodes. Symbiotic bacteria capable of producing exoenzymes that are toxic to insects. The isolation of symbiotic bacteria accomplished by infection of obtained EPN (Belik II isolate) into Tenebrio molitor larvae. Symbiotic bacteria were isolated from the hemolymph of dead larvae on NBTA media. Isolation of symbiotic bacteria was successfully obtained two morphologically distinct bacteria: B 3.1 isolate and B 4 isolate. Both bacteria were further identified using PCR analysis of the 16S rRNA gene. Based on the sequencing results, the B 3.1 isolate was in accordance with Acinetobacter pittii strain ATCC 19004, while B 4 isolate was in accordance with bacteria Enterobacter aerogenes strain KCTC 2190. The characterization of B 3.1 isolate was shown to have similarities with Acinetobacter sp., i.e.: gram-negative, non - motile, rod-shaped, and some other characteristics of biochemical tests. While the characterization of B 4 isolate was shown to have similarities with E. aerogenes i.e.: gram-negative, rod-shaped, motile, and some other characteristics of biochemical tests. These findings will be the potential to be applied as biological agents in pest control.

Thyme essential oil as an antimicrobial and biofilm inhibitory agent against abscesses with P. mirabilis Infections

IntroductionAbscesses are high density microbial infections of which biofilm formation plays a crucial role on their recurrence and chronicity. In this study, the authors aim was to determine biofilm formations of three different abscess cultures and to investigate antimicrobial and antibiofilm effects of clary sage, clove and thyme oils against the identified bacterial strain isolated from the highest biofilm forming abscess culture. MethodsThis in vitro study consisted of skin, breast and perianal abscess materials of 3 different patients. “Papanicolaou” staining and “Periodic Acid Schiff” staining methods were performed for cytological examination. Biofilm formation and biofilm inhibition tests were determined by “Crystal Violet Binding” assay and Minimum Inhibitory Concentrations (MIC) of the selected essential oils were calculated by “Micro-Dilution” method. ResultsEscherichia coli, Enterobacter aerogenes and Proteus mirabilis strains were isolated from perianal, skin and breast abscesses respectively. The bacterial strain that exists in the highest biofilm forming abscess culture was identified as P. mirabilis. P. mirabilis strain was found as resistant to Ampicillin and Trimethoprim/Sulfamethoxazole. Clary sage oil was unable to inhibit growth of P. mirabilis strain at the highest concentration tested (500 μL/mL). However, clove and thyme oils inhibited biofilm formation of P. mirabilis strain in addition to inhibiting its growth at very low concentrations (1.95 μL/mL and 0.98 μL/mL respectively). ConclusionThyme oil having the lowest inhibitory concentration and the highest antibiofilm effect has a good potential to be used as an antimicrobial and antibiofilm agent for the management of abscesses with P. mirabilis infections.

A Comparative study on plasmid isolation from strains of <em>Enterobacter aerogenes</em> using different optimized procedures

Enterobacter aerogenes are gram negative, facultative anaerobic motile bacteria which possess plasmids. Plasmids are extra chromosomal DNA. Plasmid DNA has been used as the most powerful tool in several molecular and biotechnological applications. In this current study three modified protocols were examined including mini preparation method, hot and cold alkaline lysis method and compared their simplicity, rapidity, costs and plasmid quality for extracting plasmid DNA from bacterial strains of Enterobacter aerogenes from different sources. According to the results obtained all three methods are good and yielded plasmid DNA but each methods has its advantages and disadvantages. Among all three methods, the spectrophotometric highest yield of plasmid DNA (83 ug/uL) was obtained in mini preparation method and lowest yield (20 ng/uL) in cold alkaline lysis method. The best spectrophotometric 260/280 ratio (near to 1.8) also obtained in mini preparation method which indicates the purity of extracted plasmid DNA. Among all three methods tested in this study, Mini preparation method is more efficient, time saving, non-hazardous and less cost method as it doesn’t require any expensive enzymes and hazardous chemicals.

Purification of levanase from Enterobacter aerogenes and using it as a prebiotic and antibacterial agent.

A novel strain of Enterobacter aerogenes isolated from rhizosphere soil has an ability to produce intracellular levanase when grown on basal medium containing the levan as substrate. Levanase was purified to homogeneity with a recovery yield of 57.85% and 22.5 fold of purification by using ammonium sulfate at 40% saturation followed by ion exchange chromatography on Sepharose CL-6B column and gel filtration chromatography on Sephadex G-100 column. The purified levanase has a potential prebiotic property of enhancing growth of lactic acid bacteria while apparently inhibiting growth of pathogenic bacteria. Typically, prebiotic properties should not only reduce growth of pathogens but must also promote growth of desirable and beneficial bacteria, such as Lactobacillus. Thus the levanase may be used in animal feed to improve digestibility and support gastrointestinal health.

Characterizing the Biology of Lytic Bacteriophage vB_EaeM_φEap-3 Infecting Multidrug-Resistant Enterobacter aerogenes.

Carbapenem-resistant Enterobacter aerogenes strains are a major clinical problem because of the lack of effective alternative antibiotics. However, viruses that lyze bacteria, called bacteriophages, have potential therapeutic applications in the control of antibiotic-resistant bacteria. In the present study, a lytic bacteriophage specific for E. aerogenes isolates, designated vB_EaeM_φEap-3, was characterized. Based on transmission electron microscopy analysis, phage vB_EaeM_φEap-3 was classified as a member of the family Myoviridae (order, Caudovirales). Host range determination revealed that vB_EaeM_φEap-3 lyzed 18 of the 28 E. aerogenes strains tested, while a one-step growth curve showed a short latent period and a moderate burst size. The stability of vB_EaeM_φEap-3 at various temperatures and pH levels was also examined. Genomic sequencing and bioinformatics analysis revealed that vB_EaeM_φEap-3 has a 175,814-bp double-stranded DNA genome that does not contain any genes considered undesirable for the development of therapeutics (e.g., antibiotic resistance genes, toxin-encoding genes, integrase). The phage genome contained 278 putative protein-coding genes and one tRNA gene, tRNA-Met (AUG). Phylogenetic analysis based on large terminase subunit and major capsid protein sequences suggested that vB_EaeM_φEap-3 belongs to novel genus “Kp15 virus” within the T4-like virus subfamily. Based on host range, genomic, and physiological parameters, we propose that phage vB_EaeM_φEap-3 is a suitable candidate for phage therapy applications.

Draft genome sequences of extended-spectrum β-lactamase-producing Enterobacter aerogenes isolated from swine and human.

The draft genome sequences of two Enterobacter aerogenes strains (HN503E2II and PN108E5IIB) isolated from two Cameroonian abattoirs are reported. Bacterial genomic DNA of the two isolates was sequenced using an Illumina MiSeq platform. Generated reads were de novo assembled using CLC Genomics Workbench and SPAdes. The assembled contigs were annotated, and antibiotic resistance genes, virulence factors and plasmids were identified. Whole-genome sequencing revealed that both strains were similar, with genomes of 4878638bp and 4794257bp, encoding several resistance genes associated with resistance to β-lactams, fluoroquinolones, aminoglycosides, fosfomycin, phenicols, sulphonamides, trimethoprim, macrolides and tetracycline. In silico analysis also revealed chromosomal integration of one plasmid in the genome of PN108E5IIB. The genome sequences reported here will provide useful information for a better understanding of the genetic structure of E. aerogenes in Africa.

Establishment of a Molecular Serotyping Scheme and a Multiplexed Luminex-Based Array for Enterobacter aerogenes.

Serotyping based on surface polysaccharide antigens is important for the clinical detection and epidemiological surveillance of pathogens. Polysaccharide gene clusters (PSgcs) are typically responsible for the diversity of bacterial surface polysaccharides. Through whole-genome sequencing and analysis, eight putative PSgc types were identified in 23 Enterobacter aerogenes strains from several geographic areas, allowing us to present the first molecular serotyping system for E. aerogenes. A conventional antigenic scheme was also established and correlated well with the molecular serotyping system that was based on PSgc genetic variation, indicating that PSgc-based molecular typing and immunological serology provide equally valid results. Further, a multiplex Luminex-based array was developed, and a double-blind test was conducted with 97 clinical specimens from Shanghai, China, to validate our array. The results of these analyses indicated that strains containing PSgc4 and PSgc7 comprised the predominant groups. We then examined 86 publicly available E. aerogenes strain genomes and identified an additional seven novel PSgc types, with PSgc10 being the most abundant type. In total, our study identified 15 PSgc types in E. aerogenes, providing the basis for a molecular serotyping scheme. From these results, differing epidemic patterns were identified between strains that were predominant in different regions. Our study highlights the feasibility and reliability of a serotyping system based on PSgc diversity, and for the first time, presents a molecular serotyping system, as well as an antigenic scheme for E. aerogenes, providing the basis for molecular diagnostics and epidemiological surveillance of this important emerging pathogen.

Alleviation of phytotoxic effects of cadmium on rice seedlings by cadmium resistant PGPR strain Enterobacter aerogenes MCC 3092

Heavy metal resistant PGPR mediated bioremediation, phytostimulation and stress alleviation is an eco-friendly method for sustainable agriculture in the metal contaminated soil. The isolation of such PGPR is highly demanding to reduce heavy metals in contaminated cultivated fields for agricultural benefit. The present study was successful to isolate a potent multi-heavy metal resistant PGPR strain, identified as Enterobacter aerogenes strain K6 based on MALDI-TOF MS, FAME analysis and 16S rDNA sequence homology, from rice rhizosphere contaminated with a variety of heavy metals/metalloid near industrial area. The strain exhibited high degree of resistance to Cd2+, Pb2+ and As3+ upto 4000 μg/mL, 3800 μg/mL and 1500 μg/mL respectively. Intracellular Cd accumulation of this strain was evidenced by AAS-SEM-TEM-EDX-XRF studies. Moreover, it showed several important PGP traits like IAA production, nitrogen fixation, phosphate solubilization, ACC deaminase activity even under high Cd stress (upto 3000 μg/mL). The combined effect of Cd resistance and PGP activities of this strain was manifested to the significant (p < 0.05) growth promotion of rice seedling under Cd stress by reducing oxidative stress (through antioxidants), stress ethylene and Cd uptake in seedlings. Thus K6 strain conferred Cd-tolerance in rice seedlings and could be applied as PGPR in contaminated fields.

Molecular Characterization by of Bacterial Isolates and Physicochemical Assessment of Well Water Samples from Hostels at Osekita, Iworoko-Ekiti, Ekiti State

Drinking water has been a major issue in many student hostels at Osekita in Ekiti State University, Ado-Ekiti, Nigeria and majority of the student’s populace do not have access to portable water. Only few students can afford and rely on treated water particularly for consumption therefore, underground water (well water) serve as the major source of both drinking water and domestic water used in their hostels by determining the total bacterial and coliform counts, antibiotic susceptibility of the isolated bacteria, plasmid analysis of the multiple-resistant bacteria isolates, gene sequencing of the plasmid possessed bacteria and physicochemical properties of the well water samples using standard techniques. Twelve well water samples were obtained from hostels at Osekita and analyzed. The total bacteria and coliform counts ranged from 1.0 x 105 CFU/ml to 9.7 x 105 and 1.2 x 104 CFU/ml to 6.7 x 105 CFU/ml respectively. Eight genera of bacteria were isolated from the water samples; Streptococcus spp., Pseudomonas aeruginosa, Micrococcus spp., Escherichia coli, Enterobacter spp., Klebsiella spp., Proteus spp. and Staphylococcus aureus. Streptococcus spp. showed the highest occurrence of 28.57% while Proteus spp. and Staphylococcus aureus showed the least occurrence of 3.57% among the isolated bacteria. About 68% of the isolated bacteria were resistance to at least four of the ten antibiotics used, some of which inhabited extra-chromosomal DNA (plasmid) with molecular weight of 3.0Kb. Gene sequencing clearly revealed the two organisms subjected to molecular characterization to be Escherichia coli strain s1428 and Enterobacter aerogenes strain 341. Gene sequencing revealed the resistant genes not only located on plasmids but also encoded on the organisms DNA. The physicochemical parameters were within the WHO recommended standard for portable water. Based on the microbiological standard, the water samples analyzed are not safe for consumption.

Fermentative hydrogen production from microalgal biomass by a single strain of bacterium Enterobacter aerogenes – Effect of operational conditions and fermentation kinetics

Abstract Biohydrogen production through dark fermentation is a promising technology for generating renewable energy, while using microalgal biomass as a third generation feedstock can further increase the sustainability of the process. In the present study, Scenedesmus obliquus was used as model microalga substrate for studying the impact of operational parameters in batch dark fermentation trials using a strain of Enterobacter aerogenes bacteria. (i) The initial gas-liquid ratio in the bioreactor (from 1.3 to 8.2) was tested, resulting in higher bioH2 yields for ratios above 5. (ii) Different bacterial growth, inoculation procedures and fermentation media were tested in combined experiments. The best conditions were chosen by maximising bioH2 yield and minimising production time and costs. (iii) The autoclave sterilization effect on sugar extraction and bioH2 yield was tested for different microalga concentrations (2.5–50 g/L) with best results attained for 2.5 g/L (81.2% extraction yield, 40.9 mL H2/g alga). For the best operational conditions, fermentation kinetics were monitored and adjusted to the Modified Gompertz model, with t95 (time required for bioH2 production to attain 95% of the maximum yield) below 4.5 h. The maximum hydrogen production was higher when using wet algal biomass enabling the energy consuming biomass drying step to be skipped.

Draft genome sequence of a multidrug-resistant KPC-2-producing Enterobacter aerogenes isolated from a hospitalised patient in Brazil.

Multidrug-resistant (MDR) Enterobacter aerogenes strains are frequently associated with nosocomial infections and high mortality rates, representing a serious public health problem. The aim of this study was to present the draft genome sequence of a MDR KPC-2-producing E. aerogenes isolated from a perineal swab of a hospitalised patient in Brazil. Genomic DNA was sequenced using an Illumina MiSeq platform. De novo genome assembly was carried out using the A5-Miseq pipeline, and whole-genome sequence analysis was performed using tools from the Center for Genomic Epidemiology. The strain harboured resistance genes to β-lactams, aminoglycosides, sulphonamides and trimethoprim in addition to genes encoding multidrug efflux system proteins, a quaternary ammonium transporter and heavy metal efflux system proteins. In addition, the strain harboured genes encoding diverse virulence factors. These data might allow a better understanding of the genetic basis of antimicrobial resistance and virulence in E. aerogenes strains.

BIOLOGICAL PROPERTIES OF Eugenia uniflora L. ESSENTIAL OIL: CHEMICAL COMPOSITION AND ANTIMICROBIAL ACTIVITY

Various pathologies that compromise public health are of bacterial origin. Among the species of importance to human health is Salmonella Typhimurium gastroenteritis agent, Enterobacter aerogenes and Pseudomonas aeruginosa, pathogens causing nosocomial infections in various organs. The Eugenia uniflora L., popularly known as Brazilian cherry, belonging to the Myrtaceae family is a tree native to the Brazilian Atlantic Forest found from Minas Gerais to Rio Grande do Sul. According to the popular medicine the infusion of its leaves has antimicrobial activity, astringent, antidiarrheal, carminative, diuretic, antireumatic, antipyretic, hypotensive, reducing blood cholesterol and uric acid in the urine controller. Based on the above, the study aimed to obtain the essential oil of Surinam cherry sheets, perform chemical characterization of the compounds present in the oil and evaluate the in vitro antibacterial activity on strains of Enterobacter aerogenes, Pseudomonas aeruginosa and Salmonella Typhimurium. To evaluate the antibacterial activity, we used the disk diffusion test, determination of Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC). Oil yield obtained in the extraction process was 0.65% and bactericidal action was found facing the strains of Enterobacter aerogenes and Salmonella Typhimurium with 3.125% MIC. It has been no biological action of the essential oil on Pseudomonas aeruginosa. Thus, it can be concluded that the essential oil of cherry is an alternative medical means with antibacterial action on Enterobacter aerogenes and Salmonella Typhimurium is considered possible natural source for the development of new drugs.

Production and Characterization of Halo Tolerant Alkaline Protease of Enterobacter aerogenes Strain ZB and Its Application

Production and Characterization of Halo Tolerant Alkaline Protease of Enterobacter aerogenes Strain ZB and Its Application

Optimization of Substrate Concentration for Sustainable Biohydrogen Production and Kinetics from Sugarcane Molasses: Experimental and Economical Assessment

The aim of the study was to optimize the concentration of cane molasses (10, 20, 40 and 50 g/L) for bioconversion into hydrogen through the use of pure strain of anaerobic facultative bacteria Enterobacter aerogenes. The maximum hydrogen production rate (142 mL/h), hydrogen yield (6.02 mM/g sugar) and maximum specific growth rate (0.36 h−1) of bacteria was achieved on substrate concentration of 40 g/L at 30 °C with initial pH of 6.8. The present experimental data was found to be best fitted in Moser equation (R2 = 0.98) and compared with other growth models used in the study. The comparative economic feasibility of hydrogen production was also assessed and compared with ethanol production reported in the literature and it shows a better feasibility of biohydrogen production rate of 116.9 L/L molasses/day, than the ethanol production 0.375 L/L molasses/day, production cost of bioenergy at 0.046 $/L-molasses/day and high energy recovery of 1.26 MJ/L-molasses.

Isolation and Characterization of Plant Growth Promoting Rhizobacteria From Button Mushroom Compost

An auxin-producing bacteria (strain 5-1) was isolated from button mushroom compost in Boryeong-Si, Chungcheongnam-Do. The 5-1 strain was classified as a novel strain of Enterobacter aerogenes based on chemotaxonomic and phylogenetic analyses. The isolated E. aerogenes 5-1 was confirmed to produce indole-3-acetic acid (IAA), one of the auxin hormones, using TLC and HPLC analyses. When the concentration of IAA was assessed by performing HPLC quantitative analysis, a maximum concentration of IAA of 109.9 mg L-1was detected in the culture broth incubated in R2A medium containing 0.1% L-tryptophan for 24 h at 35℃. Acidification of the culture was deemed caused by an increase of IAA because a negative relationship between IAA production and pH was observed. Supplementation with a known precursor of IAA production, L-tryptophan, appeared to induce maximal production at 0.1% concentration, but it reduced production at concentrations above 0.2%. To investigate the growth-promoting effects to crops, the culture broth of E. aerogenes 5-1 was used to inoculate water cultures and seed pots of mung bean and lettuce. In consequence, adventitious root induction and root growth of mung bean and lettuce were two times higher than those of the control.