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In the current study, a soil bacterial isolate F2 expressed a significant antagonistic activity against Candida albicans ATCC 10231 and Aspergillus niger clinical isolate confirmed through cross streak, dual culture, and agar well diffusion methods. The isolate F2 was identified using phenotypic and molecular approaches as Alcaligenes (A.) faecalis MT332429. The identification and structural characterization of the antifungal compound was performed using advanced spectroscopic techniques including UV absorbance, 1H and 13C NMR and 2D NMR (COSY, HSQC, and HMBC) and was identified as octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propanoate. Response surface methodology (RSM) using a central composite design was employed to optimize the nutritional and cultural variables affecting the antifungal metabolite yield. The optimum conditions were found to be temperature 30 °C, agitation 150 rpm, glucose 1 g/l, peptone 2 g/l, and pH 8. A confirmatory experiment was performed to assess the accuracy of the optimization procedure, where an increase in the antifungal metabolite production by about 2.48-fold was obtained. To the best of our knowledge, this is the first report of octadecyl 3-(3, 5-di-tert-butyl-4-hydroxyphenyl) propanoate recovered from the culture broth of A. faecalis MT332429 with a promising antifungal activity along with its optimized production through RSM. Key points: • A novel soil bacterial isolate, F2, identified as Alcaligenes faecalis MT332429, showed significant antagonistic activity against Candida albicans ATCC 10231 and Aspergillus niger clinical isolate. • This stable fungicidal extracellular metabolite was identified as octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propanoate. • Optimization using central composite design resulted in 2.48-fold increase in production reaching 213.82 μg/ml. [ABSTRACT FROM AUTHOR]

In wastewater treatment, ammonia oxidizing bacteria (AOB) can directly use hydroxylamine and NH3, but these bacteria grow slowly and have additional nutrient requirements. In contrast, Alcaligenes faecalis, a recently discovered functional bacterium, is able to conduct both heterotrophic nitrification and aerobic denitrification. Moreover, A. faecalis can produce hydroxylamine to support the growth of AOB. Therefore, it is expected that a co-culture system of these two bacteria may achieve better synergistic denitrification. In this study, the effects of environmental factors on the synergistic nitrogen- removal efficiency of A. faecalis No.4 and AOB were investigated. The experimental results showed that the nitrogen-removal rate decreased with an increase in the medium carbon-to-nitro-gen (C/N) ratio (from 1:1 to 3:1), whereas it increased with an increase in the stirring speed, which indicated that a low medium C/N ratio and a high stir speed benefited the synergistic denitrification of A. faecalis and AOB. In addition, the heterotrophic nitrification of A. faecalis and the ammonia oxidation of AOB proceeded better at 25°C than at 15°C. Further study revealed that, to some extent, the synergistic denitrification of A. faecalis and AOB increased with increases in the ratio of A. faecalis to AOB, and that high concentrations of A. faecalis did not inhibit AOB. The findings of this study are expected to enable the development of a new method for the removal of nitrogen from sewage and provide a theoretical basis for applications to AOB engineering. [ABSTRACT FROM AUTHOR]

Coleus forskohlii is an herb, well-known for its medicinal compound forskolin present in its roots, with wide range of pharmaceutical applications. Here, we report, for the first time, the role of plant–probiotic bacterial endophytes of C. forskohlii, CFLB1 and CFRB1, isolated from leaf and root, which regulate plant growth and in plant forskolin content. Native bacterial endophyte, CFRB1 (Alcaligenes faecalis), significantly modulates primary plant productivity and forskolin content under pot and field conditions. Under field conditions, CFRB1 endophyte application significantly enhanced photosynthetic pigments and reduced the severity of root-knot and root rot diseases. Expression analyses of functional genes involved in the forskolin biosynthesis in C. forskohlii plants treated with CFRB1 endophyte under field conditions revealed differential upregulation of four C. forskohlii diterpene synthases (CfTPSs), CfTPS1, CfTPS2, CfTPS3 and CfTPS4, along with cytochrome P450 (CfCYP76AH15) and acyltransferase (CfACT1–8) genes. CFRB1 treatment reduced the severity of nematode infection and root rot in C. forskohlii plants by 81 and 78%, respectively. Overall, we demonstrate that cross-talk of plant–endophyte interaction in C. forskohlii is beneficial, leading to enhanced forskolin content through modulation of forskolin biosynthetic pathway genes along with increased plant yield and reduced disease incidence. Thus, endophytic isolate, A. faecalis (CFRB1), could be deployed as a novel bio-stimulant for enhancing in planta forskolin content during cultivation of C. forskohlii. [ABSTRACT FROM AUTHOR]

This study involved therapeutic targets mining for the extremely drug-resistant bacterial species called Alcaligenes faecalis, which is known to infect humans. The infections caused by this species in different parts of the human body have been linked with a higher degree of resistance to several classes of antibiotics. Meanwhile, alternate therapeutic options are needed to treat these bacterial infections in clinical settings. In the current study, a subtractive proteomics approach was adapted to annotate the whole proteome of Alcaligenes faecalis and prioritize target proteins for vaccine-related therapeutics design. This was followed by targeted protein-specific immune epitope prediction and prioritization. The shortlisted epitopes were further subjected to structural design and in silico validation of putative vaccines against Alcaligenes faecalis. The final vaccine designs were also evaluated for potential interaction analysis with human TLR-2 through molecular docking. Finally, the putative vaccines were subjected to in silico cloning and immune simulation approaches to ensure the feasibility of the target-specific vaccine constructs in further experimental designs.

The continuous development of multidrug resistance pathogens with limited therapeutic options has become a great problem globally that impose sever health hazards. Accordingly, searching for of new antimicrobials became an urgent demand and great challenge. Soil significantly have been associated with several species that are antibiotic producers. In this study, combination of conventional screening methods with Liquid chromatography- Mass spectroscopy (LC/MS) and metagenomic nanopore sequence analysis have been conducted for the deciphering the active metabolites produced by soil isolate(s). Preliminary soil screening resulted in a Gram-negative isolate identified via 16S ribosomal RNA as Alcaligenes faecalis isolate MZ921504 with promising antimicrobial activities against wide range of MDR gram-positive and gram-negative pathogens. The LC/MS analysis of the metabolites of A. faecalis isolate MZ921504 confirmed the presence of ectoine, bacillibactin, quinolobactin and burkholderic acid. Metagenomics sequence analysis of the soil sample (NCBI GenBank accession PRJNA771993) revealed the presence of conserved biosynthetic gene clusters of ectoine, bacteriocin, bacillibactin, quinolobactin, terpene and burkholderic acid of A. faecalis. In conclusion, A. faecalis isolate MZ921504 is a promising source for antimicrobial metabolites. LC/MS spectral analysis and third generation sequencing tools followed by secondary metabolite gene clusters analysis are useful methods to predict the nature of the antimicrobial metabolites.

By conducting three different methods, we report on the isolation of five novel strains of non-symbiotic bacteria from crushed infective juveniles (IJs) of four species of entomopathogenic nematodes (EPN) including Heterorhabditis bacteriophora, Steinernema carpocapsae, Steinernema feltiae, and Steinernema glaseri and five bacterial species from hemolymph of insect larvae infected with EPNs. Samples of hemolymph of infected Galleria mellonella L. larvae by EPNs and crushed surface sterilized IJs were bulk streaked onto both MacConkey and NBTA agar. To further ensure diagnoses, extracted DNA from IJs bulk was subjected to PCR by 16S-rRNA bacterial universal primers. Bacteria were identified using biochemical and phylogenetic analysis. Based on 16S-rRNA gene sequence, maximum parsimony, maximum likelihood and neighbour joining phylogenetic analyses were conducted, as well as comparisons of predicted RNA secondary structures. Four species of bacteria were identified including: Stenotrophomonas maltophilia strain IR11 from S. feltiae; S. pavanii strain IR20 from S. glaseri; Acinetobacter junii strain IR8 from S. carpocapsae; and Alcaligenes faecalis strains IR1 & IR15 from S. feltiae and H. bacteriophora respectively as non-symbiotic bacteria from IJs and five species probably originated from G. mellonella intestine including Citrobacter gillenii isolate S3, Enterobacter asburiae isolate S4, Klebsiella oxytoca isolate S5, Morganella morganii isolate S6 and Serratia marcescens isolate S6.

Background and Objectives: Fibrinolytic drugs are commonly used for fibrin clot lysis but due to their inappropriate side effects, as well as their high costs, using fibrinolytic enzymes has been paid attention. Bacterial sources of this enzyme are a good alternative for this purpose. The aim was fibrinolysin production through screening of fibrinolysin producing bacteria from environmental samples. Materials and Methods: Bacterial isolation was performed from different environmental samples and was screened based on sheep blood clot digestion and culture on plasma plate. The most potent isolate was optimized for different growth parameters including temperature, pH and fibrinolysin production at optimum growth conditions. The stability of produced enzyme at various temperatures and pH and treatment with MgSO4, NiSO4, SDS and EDTA was then investigated. Finally this isolate was identified based on the 16S rRNA sequencing. Results: As a result, from 79 different isolates, the most potent fibrinolysin producer was identified as Alcaligenes faecalis strain 26. This isolate produced 12 mm halo zone on plasma plate. Its optimum growth temperature and pH was 43°C and 7, respectively. The produced enzyme had the best stability at pH 7 and was also active up to 60°C. The fibrinolytic activity of this isolate was reduced following treatment with MgSO4, NiSO4 and also with protease inhibitors, such as SDS and EDTA. Conclusion: Based on the obtained results it can be suggested that Alcaligenes faecalis strain 26 has appropriate efficiency for fibrinolysin production that can be used in food industry and medicine.

Controlling aflatoxigenic Aspergillus flavus and aflatoxins (AFs) in grains and food during storage is a great challenge to humans worldwide. Alcaligenes faecalis N1-4 isolated from tea rhizosphere soil can produce abundant antifungal volatiles, and greatly inhibited the growth of A. flavus in un-contacted face-to-face dual culture testing. Gas chromatography tandem mass spectrometry revealed that dimethyl disulfide (DMDS) and methyl isovalerate (MI) were two abundant compounds in the volatile profiles of N1-4. DMDS was found to have the highest relative abundance (69.90%, to the total peak area) in N1-4, which prevented the conidia germination and mycelial growth of A. flavus at 50 and 100 μL/L, respectively. The effective concentration for MI against A. flavus is 200 μL/L. Additionally, Real-time quantitative PCR analysis proved that the expression of 12 important genes in aflatoxin biosynthesis pathway was reduced by these volatiles, and eight genes were down regulated by 4.39 to 32.25-folds compared to control treatment with significant differences. And the A. flavus infection and AFs contamination in groundnut, maize, rice and soybean of high water activity were completely inhibited by volatiles from N1-4 in storage. Scanning electron microscope further proved that A. flavus conidia inoculated on peanuts surface were severely damaged by volatiles from N1-4. Furthermore, strain N1-4 showed broad and antifungal activity to other six important plant pathogens including Fusarium graminearum, F. equiseti, Alternaria alternata, Botrytis cinerea, Aspergillus niger, and Colletotrichum graminicola. Thus, A. faecalis N1-4 and volatile DMDS and MI may have potential to be used as biocontrol agents to control A. flavus and AFs during storage.

A total of 24 morphologically distinct salt-tolerant bacteria were isolated from the tomato rhizosphere soil and tested in vitro against Pythium aphanidermatum, causing damping-off disease in tomato. Among them, five bacterial isolates viz., BTR1.0, BTR1.1, BTR4.4, BTR7.0 and BTR8.6 were found to inhibit the mycelial growth of P. aphanidermatum. The maximum antagonistic effect was shown by BTR1.0 followed by BTR7.0 and BTR1.1. Based on the MALDI Biotyper analysis, these bacterial isolates were identified as Serratia marcescens (BTR1.0 and BTR1.1), Pseudomonas aeruginosa (BTR7.0 and BTR8.6) and Alcaligenes faecalis (BTR4.4). Analysis of plant growth stimulating activity of bacterial strains revealed that A. faecalis BTR4.4 recorded the highest vigour index followed by S. marcescens BTR1.0. The biocontrol activity of bacterial antagonists against tomato damping-off was tested under salt-water irrigation. Among the bacterial strains tested, S. marcescens BTR1.1 was found to be highly effective under non-saline water irrigation, which suppressed the disease by 68% compared to infected control. However, at 50 mM NaCl concentration, S. marcescens strain BTR1.0, P. aeruginosa strain BTR7.0 and A. faecalis BTR4.4 provided a significant level of control of the disease. At 100 mM NaCl concentration, no significant effect of the bacterial strains on the disease incidence was observed. [ABSTRACT FROM AUTHOR]

One hundred and fifty six native bacterial strains with different morphological characters were isolated from water and soil samples collected from textile wastewater effluent sites, Sri Lanka. Three isolated bacterial strains were more effective on decolorization of CI Direct Blue 201 textile dye and 16s rRNA analysis reveals that the bacterial strains were Alcaligenes faecalis (MK166784), Micrococcus luteus (MK166783) and Staphylococcus warneri (MK256311). A. faecalis, M. luteus and S. warneri showed complete decolorization of CI Direct Blue 201 textile dye within 60, 64, and 72 h of incubation time respectively under the static conditions at 28 oC. Decolorization was effective at a temperature range from 24 oC to 40 oC and pH range from 7 to 9. The presence of tryptone, peptone or yeast in the Mineral Salt Medium enhanced the decolorization of the dye. Phytotoxicity assay based on the seed germination percentages of Oryza sativa and Vigna radiate showed that the detoxification of CI Direct Blue 201 textile dye after the bacterial treatment was effective signifying the potential applicability of the A. faecalis, M. luteus and S. warneri to develop a green application to treat textile wastewater. [ABSTRACT FROM AUTHOR]

Photocatalytic removal of U(VI) has attracted much attention due to its advantages such as no secondary pollution and less energy consumption. Synergistic removal of U(VI) by Alcaligenes faecalis and exogenous electron shuttle AQS (anthraguinone-2-sulfonate) under illumination condition was investigated. The results show that 0.16 g L−1 AQS can apparently accelerate the electron transfer and promote the growth of A. faecalis. The reduction rate of U(VI) enhances by 17.50%. The maximum removal efficiency of U(VI) reaches up to 80.7%. These results suggest that proper exogenous electron shuttles can accelerate photocatalytic removal of U(VI) cooperating with microorganisms. [ABSTRACT FROM AUTHOR]

Background and Objectives: Fibrinolytic drugs are commonly used for fibrin clot lysis but due to their inappropriate side effects, as well as their high costs, using fibrinolytic enzymes has been paid attention. Bacterial sources of this enzyme are a good alternative for this purpose. The aim was fibrinolysin production through screening of fibrinolysin producing bacteria from environmental samples. Materials and Methods: Bacterial isolation was performed from different environmental samples and was screened based on sheep blood clot digestion and culture on plasma plate. The most potent isolate was optimized for different growth parameters including temperature, pH and fibrinolysin production at optimum growth conditions. The stability of produced enzyme at various temperatures and pH and treatment with MgSO4, NiSO4, SDS and EDTA was then investigated. Finally this isolate was identified based on the 16S rRNA sequencing. Results: As a result, from 79 different isolates, the most potent fibrinolysin producer was identified as Alcaligenes faecalis strain 26. This isolate produced 12 mm halo zone on plasma plate. Its optimum growth temperature and pH was 43°C and 7, respectively. The produced enzyme had the best stability at pH 7 and was also active up to 60°C. The fibrinolytic activity of this isolate was reduced following treatment with MgSO4, NiSO4 and also with protease inhibitors, such as SDS and EDTA. Conclusion: Based on the obtained results it can be suggested that Alcaligenes faecalis strain 26 has appropriate efficiency for fibrinolysin production that can be used in food industry and medicine. [ABSTRACT FROM AUTHOR]

Aim. Detection of representatives of saprophytic (Bacillus thuringiensis, Alcaligenes faecalis, Lactobacillus plantarum) and pathogenic (Agrobacterium spp.) microbiota in flowers and berries of grape. Materials and Methods. Flowers, non-damaged green and ripe berries of grape were selected from a vineyard of Vitis vinifera L. cv Pinot noir located in Odessa region in May, July and September 2018, accordingly. Flowers or berries were homogenized and left for autofermentation process for 7 days. Real-Time polymerase chain reaction to detect species B. thuringiensis, L. plantarum, A. faecalis and Agrobacterium tumefaciens, Agrobacterium vitis was carried out with DNA isolated from the resulted fermented homogenate. Results. B. thuringiensis was prevalent among the tested species: these bacteria were identified in 50% of samples of grape flowers, in 90% of green berries and 20% of samples of ripe berries. L. plantarum was not detected in flowers, but these bacteria were identified in green and ripe berries (10% of tested samples). Results confirm literature data about the presence of B. thuringiensis and L. plantarum on grape. For the first time, we detected A. faecalis and Agrobacterium spp. in flowers and berries of grape. A. faecalis was found in 20% of flower samples, 60% of green berries and 20% of ripe berries. Agrobacterium spp. were detected in flowers and green berries (10% of samples), and in ripe berries these microorganisms were not found. Amount of detected species increased in green berries compared with the flowers, and decreased in ripe berries. Conclusions. For the first time, we detected A. faecalis and Agrobacterium spp. in flowers and berries of grape. Coexistence of phytopathogenic agrobacteria and their potential antagonists -- Bacillus thuringiensis, Alcaligenes faecalis and Lactobacillus plantarum in one ecological niche (flowers and green grape berries) was revealed. [ABSTRACT FROM AUTHOR]

Controlling aflatoxigenic Aspergillus flavus and aflatoxins (AFs) in grains and food during storage is a great challenge to humans worldwide. Alcaligenes faecalis N1-4 isolated from tea rhizosphere soil can produce abundant antifungal volatiles, and greatly inhibited the growth of A. flavus in un-contacted face-to-face dual culture testing. Gas chromatography tandem mass spectrometry revealed that dimethyl disulfide (DMDS) and methyl isovalerate (MI) were two abundant compounds in the volatile profiles of N1-4. DMDS was found to have the highest relative abundance (69.90%, to the total peak area) in N1-4, which prevented the conidia germination and mycelial growth of A. flavus at 50 and 100 μL/L, respectively. The effective concentration for MI against A. flavus is 200 μL/L. Additionally, Real-time quantitative PCR analysis proved that the expression of 12 important genes in aflatoxin biosynthesis pathway was reduced by these volatiles, and eight genes were down regulated by 4.39 to 32.25-folds compared to control treatment with significant differences. And the A. flavus infection and AFs contamination in groundnut, maize, rice and soybean of high water activity were completely inhibited by volatiles from N1-4 in storage. Scanning electron microscope further proved that A. flavus conidia inoculated on peanuts surface were severely damaged by volatiles from N1-4. Furthermore, strain N1-4 showed broad and antifungal activity to other six important plant pathogens including Fusarium graminearum, F. equiseti, Alternaria alternata, Botrytis cinerea, Aspergillus niger , and Colletotrichum graminicola. Thus, A. faecalis N1-4 and volatile DMDS and MI may have potential to be used as biocontrol agents to control A. flavus and AFs during storage. [ABSTRACT FROM AUTHOR]

Summary: Soil‐dwelling entomopathogenic nematodes (EPNs) kill arthropod hosts by injecting their symbiotic bacteria into the host hemolymph and feed on the bacteria and the tissue of the dying host for several generations cycles until the arthropod cadaver is completely depleted. The EPN–bacteria–arthropod cadaver complex represents a rich energy source for the surrounding opportunistic soil fungal biota and other competitors. We hypothesized that EPNs need to protect their food source until depletion and that the EPN symbiotic bacteria produce volatile and non‐volatile exudations that deter different soil fungal groups in the soil. We isolated the symbiotic bacteria species (Alcaligenes faecalis) from the EPN Oscheius spp. and ran infectivity bioassays against entomopathogenic fungi (EPF) as well as against plant pathogenic fungi (PPF). We found that both volatile and non‐volatile symbiotic bacterial exudations had negative effects on both EPF and PPF. Such deterrent function on functionally different fungal strains suggests a common mode of action of A. faecalis bacterial exudates, which has the potential to influence the structure of soil microbial communities, and could be integrated into pest management programs for increasing crop protection against fungal pathogens. [ABSTRACT FROM AUTHOR]

ظهور مقاومت هایدارویی در بین میکروارگانیسم های بیماریزا نشان دهنده نیاز به کشف آنتی بیوتیک هایجدید است. در جستجوی یک میکروارگانیسم تولید کننده ماده ضد میکروبی جدید از خاکهای آلوده به نفت اطراف دزفول یک سویه subsp. faecalis Alcaligenes faecalis جداسازی گردید. عوامل موثردر تولید ماده ضد میکروبی به روش یک فاکتور در هر زمان تعیین گردید که بر اساس آن بهترتیب 9 pH =، دما °C35، % 34/0NH4Cl، % 2 استات سدیم و % 02/0 K2HPO4بیشترین تاثیر را داشت. بر اساس این نتایج غلظت استات و NH4Cl،دور همزن و زمان فرمانتاسیون به روش سطح پاسخ با طراحی مرکب مرکزی بهینه شدند.بهترین شرایط % 88/1 استات، % 29/0 NH4Cl، دور همزن rpm 3 و زمان 7/6روز تعیین گردید که باعث افزایش %47 در تولید گردید. همچنین مشخص گردید که در بین متغیرها برهم کنش وجود دارد.

Bacterial co-infections have been reported in association with dengue fever (DF) and can exacerbate dengue infections. However, DF with acute respiratory distress syndrome and co-infection with Alcaligenes faecalis (A. faecalis) has not been reported earlier. Most infections caused by A. faecalis are opportunistic. Urinary tract infection, bacterial keratitis, postoperative endophthalmitis, skin and soft tissue infections, bacteremia, meningitis, wound infections, and peritonitis in patients undergoing peritoneal dialysis have been described in association with A. faecalis. A. faecalis, a Gram-negative environmental organism rarely cause significant infections. Treatment can be difficult in some cases due to the high level of resistance to commonly used antibiotics. We report a case of fatal bronchopneumonia caused by extensively drug resistance A. faecalis in a patient of dengue hemorrhagic fever.

We found that 20 (10.6%) of 188 patients with chronic suppurative otitis media in Angola were co-colonized with fluoroquinolone-resistant Alcaligenes faecalis, commonly found in birds. A likely explanation for our findings was the use of bird feces by residents as a traditional remedy to prevent ear secretions caused by primary ear infection.

Alcaligenes spp. are identified as commensal bacteria and have been found to inhabit Peyer’s patches in the gut. We previously reported that Alcaligenes-derived lipopolysaccharides (LPS) exerted adjuvant activity in systemic vaccination, without excessive inflammation. Lipid A is one of the components responsible for the biological effect of LPS and has previously been applied as an adjuvant. Here, we examined the adjuvant activity and safety of chemically synthesized Alcaligenes lipid A. We found that levels of OVA-specific serum IgG antibodies increased in mice that were subcutaneously immunized with ovalbumin (OVA) plus Alcaligenes lipid A relative to those that were immunized with OVA alone. In addition, Alcaligenes lipid A promoted antigen-specific T helper 17 (Th17) responses in the spleen; upregulated the expression of MHC class II, CD40, CD80, and CD86 on bone marrow-derived dendritic cells (BMDCs); enhanced the production of Th17-inducing cytokines IL-6 and IL-23 from BMDCs. Stimulation with Alcaligenes lipid A also induced the production of IL-6 and IL-1β in human peripheral blood mononuclear cells. Moreover, Alcaligenes lipid A caused minor side effects, such as lymphopenia and thrombocytopenia. These findings suggest that Alcaligenes lipid A is a safe and effective Th17-type adjuvant by directly stimulating dendritic cells in systemic vaccination.

Background: Infectious diseases due to antibiotic resistant pathogens are a global public health problem. This study aimed at determining the potential effect of bacterial-fungal interaction on the antibiotic susceptibility profile of Alcaligenes faecalis., Materials and Methods: Alcaligenes faecalis was isolated from water samples. The isolate was identified using the conventional biochemical tests and the 16S rRNA molecular sequencing technique. Additionally, Penicillium species was isolated and identified based on colony morphological characteristics and microscopic features. Standardized isolates were co-cultured in broth medium. Antibiotic susceptibility evaluation of the Alcaligenes faecalis from the co-culture and the original Alcaligenes faecalis was carried out using the Kirby bauer disk diffusion method., Results: The antibiotic susceptibility profile of Alcaligenes faecalis before and after co-culture remained largely unchanged except in the case of chloramphenicol, where the isolate showed reduced susceptibility. Molecular analysis of resistance gene revealed the absence of tested gene encoding antibiotic resistance, including the streptomycin resistance (str) genes ( stra and strb ) and the erythromycin resistance methylase ( erm ) gene., Conclusion: The result of this study showed that there is a minimal influence of Penicillium cultures on the susceptibility of A. faecalis . Further research involving a wide spectrum of microorganisms and their interactions should be conducted to acquire a thorough understanding of the influence of microbial interactions on antibiotic susceptibility profiles in order to pave way for novel strategies to combat antimicrobial resistance., Competing Interests: The author declares that there are no competing interests associated with this study. List of Abbreviations:UTIs -urinary tract infectionsEMB -Eosin methylene blueMHA -Mueller Hinton agarDNA -deoxyribonucleic acidPCR -polymerase chain reaction, (Copyright: © 2024 Afr. J. Infect. Diseases.)

Heterotrophic nitrification remains a mystery for decades. It has been commonly hypothesized that heterotrophic nitrifiers oxidize ammonia to hydroxylamine and then to nitrite in a way similar to autotrophic AOA and AOB. Recently, heterotrophic nitrifiers from Alcaligenes were found to oxidize ammonia to hydroxylamine and then to N2 ("dirammox", direct ammonia oxidation) by the gene cluster dnfABC with a yet-to-be-reported mechanism. The role of a potential glutamine amidotransferase DnfC clues the heterotrophic ammonia oxidation might involving in glutamine. Here, we found Alcaligenes faecalis JQ135 could oxidize amino acids besides ammonia. We discovered that glutamine is an intermediate of the dirammox pathway and the glutamine synthetase gene glnA is essential for both A. faecalis JQ135 and the Escherichia coli cells harboring dnfABC gene cluster to oxidize amino acids and ammonia. Our study expands understanding of heterotrophic nitrifiers and challenges the classical paradigm of heterotrophic nitrification., (© The Author(s) 2024. Published by Oxford University Press on behalf of the International Society for Microbial Ecology.)

Graphical abstract Highlights • Drying kinetics of orange peel for effective waste biomass utilization. • Saccharification and detoxification of orange peel substrate for curdlan biosynthesis. • Highest curdlan production (P m = 23.24 g/L) with maximum specific growth rate (μ m = 0.23/h). • Qualitative characterization of curdlan with average M w of 5.2 × 105 Da. Abstract This study presents an engineered approach for sustainable biosynthesis of curdlan by Alcaligenes faecalis using orange peels. To confirm the substrate suitability a four step study was organized. Firstly, drying of substrate was carried within temperature range of 60–120 °C, along with the application of moisture diffusion control model. Secondly, fermentation medium was obtained via saccharification and detoxification, releasing highest sugar at 72.34 g/L with phenolics removal of 95–98%. Thirdly, curdlan fermentation was conducted in detoxified orange peel hydrolysate followed by optimization of batch culture fermentation via kinetic modeling using Logistic and Luedeking-Piret equations. In 5 L bioreactor, highest specific growth rate (μ m = 0.233/h), highest curdlan production (P m = 23.24 g/L) and growth associated rate constant (α = 3.403) were achieved. Moreover, the total sugar consumption and conversion rates were 83.27% and 53.20%. Lastly, characterization techniques such as FTIR, NMR, XRD, TGA, HPGPC and EDS were applied to biosynthesized curdlan for qualitative validation. [ABSTRACT FROM AUTHOR]

Nicotinic acid (NA), known as vitamin B3, is ubiquitous in nature and plays an important role in living organisms. The microbial catabolism of NA is highly diverse. However, the NA degradation by Alcaligenes faecalis strains has been poorly investigated. In this study, we report the complete genome sequence of A. faecalis JQ135 (4.08 Mbp) and several essential genes for NA degradation. This genome sequence will facilitate to elucidate the molecular metabolism of NA and advance the potential biotechnological applications of A. faecalis strains. [ABSTRACT FROM AUTHOR]

Methane (CH4) and nitrous oxide (N2O) emissions from two-stage membrane bioreactor (MBR) bio-augmented by Alcaligenes faecalis no. 4 during municipal solid waste leachate treatment were investigated. The system was operated at hydraulic retention time (HRT) of 2.5 and 1 days in each reactor under the presence and absence of sludge recirculation. Alcaligenes faecalis no. 4 bioaugmentation helped improving organic carbon and nitrogen removals while reducing CH4 and N2O emissions. CH4 and N2O emissions were decreased by 46% and 85% when A. faecalis no. 4 was introduced at HRT of 2.5 days. Under the presence of A. faecalis no. 4, the operation of twostage MBR with sludge recirculation could reduce CH4 and N2O emissions by 51% and 54% as compared to its operation without sludge recirculation. An operation under short HRT of 1 day also yielded high organic carbon and nitrogen removals of more than 85% while emitting lower CH4 and N2O emission of 6.7% C and 0.04% N when operated with sludge recirculation. Implications: A two-stage membrane bioreactor was effectively applied to the treatment of concentrated leachate (BOD~20,000 mg/L) at a short hydraulic retention time of 2.5 days and 1 day. About 80% of CH4 and N2O was emitted from the anaerobic and aerobic reactors, respectively. Introduction of Alcaligenes faecalis no. 4 reduced CH4 and N2O emissions in both reactors as it became the predominant microorganism under an elevated pH condition. Lower CH4 and N2O emissions were achieved under a sludge recirculation operation, as Alcaligenes faecalis no. 4 could suppress methanogenic activities in the anaerobic reactor and converted a majority of nitrogen into its cell mass, thus reducing N2O production through a biological nitrification-denitrification pathway. [ABSTRACT FROM AUTHOR]

Pseudo-persistent organic pollutants, such as anionic surfactants (AS), are nowadays among the more complex problems that threaten the aquatic environments and other environmental compartments. The present work describes the identification and efficiency of a consortium, isolated from Algerian industrial wastewater, to remove three anionic surfactants (i.e., sodium dodecylbenzenesulfonate (SDBS), sodium dodecyl sulfate (SDS) and sodium lauryl ether sulfate (SLES)). The genetic analysis of 16S rRNA indicated that these strains are Alcaligenes faecalis , Enterobacter cloacae and Serratia marcescens . Under aerobic conditions, pH 7.0 and optimum temperature of 30 °C, the mixed consortium allowed to degrade 85.1% of initial SDBS amount after 144 h of incubation with half-life of 20.8 h. While E. cloacae and S. marcescens pure strains eliminated 46% and 41% less SDBS respectively. Evenly, SDS was degraded at only 23.71% by A. faecalis strain. However, the degradation capacity of SDS by the consortium was very high (94.2%) with a half-life of 9.8 h. The SLES anionic surfactant showed a lower biodegradation by the consortium (47.53%) due to the presence of ether oxide units in the chemical structure of SLES which induced toxicity to the medium. The investigation of the biodegradation of this type of organic pollutants by microorganisms has recently become a key issue for the environmental protection area. [ABSTRACT FROM AUTHOR]

In textile industry, untreated effluents pollute aquatic systems, almost irreversibly. Synthetic dyes not only change the colour of water resources but also make them toxic. In this study, we evaluated decolourizing potential of microbial isolates so as to use them as bioremediation agents. Two bacterial isolates, Bacillus flexus and Alcaligenes faecalis were isolated from the textile effluent samples collected from Nahar textile industry, Lalru (Punjab). Both these isolates have high decolourization potential and take only 24 h for complete decolourization. Different parameters, such as carbon source, nitrogen source, temperature, pH, concentration of dyes and inoculum size were optimized for decolourization of remazol black, direct blue and acid orange which are azo dyes that are most widely used and are highly toxic. Bacillus flexus showed 100% decolourization after 20 h with acid orange and at 24 h for remazol black and direct blue. Alcaligenes faecalis showed the best incubation time for all the three dyes to be 24 h and the extent of decolourization was found to be 89, 98 and 100% for remazol black, direct blue and acid, respectively. Such decolourizing potential of the isolates is quite high as compared to the earlier reports and can be effectively used as a tool for bioremediation of various textile effluents. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Hyperinduction of nitrilase by inducer feeding approach. • Nitrilase mediated biotransformation of 4-hydroxyphenylacetonitrile. • Bioprocess development for 4-hydroxyphenylacetic acid synthesis. • Fed batch synthesis at 500 ml scale. Abstract The whole cell arylacetonitrilase of Alcaligenes faecalis MTCC 12629 was employed to develop a bioprocess for the synthesis of 4-hydroxyphenylacetic acid (4-HPAA) from 4-hydroxyphenylacetonitrile (4-HPAN). Isobutyronitrile emerged as the most appropriate inducer with a 1.2-fold enhanced nitrilase production in inducer feeding approach. A. faecalis MTCC 12629 nitrilase preferably hydrolyzed 4-HPAN, 4-aminoyphenylacetonitrile, mandelonitrile and phenylacetonitrile to their corresponding acids. Thermostability profile revealed the stability of nitrilase at 40, 45 and 50°C with the half-life of 45 h, 36 h and 13 h, respectively. Michaelis constant (K m) and reaction velocity (V max) of nitrilase were calculated as 20 mM and 2 U/mg dcw, respectively. This nitrilase exhibited complete conversion of 4-HPAN to 4-HPAA at 45°C in 50 mM K 2 HPO 4 /KH 2 PO 4 buffer (pH 7.0) in 30 min. A fed batch process designed at 500 ml with five feedings of substrate resulted in 150 mM product formation using 18 U/ml whole cells nitrilase (16 mg/ml dcw) at 45°C. This is the first report on the production of 4-HPAA through nitrilase mediated pathway with the volumetric and catalytic productivity of 23 g/l and 4.13 g/g dcw/h, respectively. [ABSTRACT FROM AUTHOR]

Introduction: Alcaligenes faecalis is a common environmental bacteria that often infects human as an opportunistic pathogen. It rarely causes Urinary Tract Infection (UTI) in human; however, infection brings severe outcomes. Also, the treatment of A. faecalis associated infections with common antibiotics can be difficult due to a high level of antibiotic resistance. Aim: Molecular characterisation of A. faecalis isolate from women suffering from Recurrent Urinary Tract Infections (RUTIs). Materials and Methods: The study has been conducted in the USDA-laboratory of the Department of Genetic Engineering and Biotechnology, Shahjalal University of Science and Technology, Sylhet, Bangladesh. The present study conducted from July 2017 to December 2017, characterised an A. faecalis strain from the women suffering from RUTIs by applying 16s rRNA gene sequencing and phylogenetic analysis. Antibiogram profiling was done by means of disk diffusion assay. Analysis of in-silico SNP variants was done using Geneious software. Results: The isolates were resistant to seven out of ten commercial antibiotics used to treat UTI in Bangladesh. Phylogenetic and evolutionary distance data analysis revealed a close proximity of the study AF1 strain with other A. faecalis strains identified from the environment, especially from a previously characterised water sample. In-silico variants search found nine potentials of Single Nucleotide Polymorphism (SNPs) in the studied strain compared to other environmental A. faecalis bacteria characterised from India, South-Korea, Japan, Mexico and Brazil. Conclusion: The present study revealed the transmission of environmental opportunistic pathogens to human and cause chronic infections in Bangladesh. [ABSTRACT FROM AUTHOR]

Alcaligenes faecalis LJ-3 is highly efficient in degrading various azo dyes (100 mg L-1). Almost 100 % degradation was observed within 16 h at the initial Acid Scarlet 3R concentrations of 1000 mg L-1 under the optimal conditions, which were: 1 g dextrin L-1, 3 g yeast extract L-1, NaCl ≤ 30 g L-1, pH 8.0 and 35-45 ºC. Azoreductase, laccase and NADH-DCIP (nicotinamide adenine dinucleotide-dichlorophenol indophenols) reductase were induced during the degradation of Acid Scarlet 3R. Kinetics study of degradation experiments approximated the first-order reaction. The maximum rate (Vmax) and substrate affinity constant (Ks) were found to be 115.90 mg L-1 h-1 and 1193.23 mg L-1, respectively, using Michaelis-Menten kinetics. This work provides new data characterizing Acid Scarlet 3R degradation by bacteria, as well as practical application potential in biological treatment of industrial effluents containing various azo dyes. [ABSTRACT FROM AUTHOR]

5-Hydroxypicolinic acid (5HPA), a natural pyridine derivative, is microbially degraded in the environment. However, the physiological, biochemical, and genetic foundations of 5HPA metabolism remain unknown. In this study, an operon (hpa), responsible for 5HPA degradation, was cloned from Alcaligenes faecalis JQ135. HpaM was a monocomponent flavin adenine dinucleotide (FAD)-dependent monooxygenase and shared low identity (only 28 to 31%) with reported monooxygenases. HpaM catalyzed the ortho decarboxylative hydroxylation of 5HPA, generating 2,5-dihydroxypyridine (2,5DHP). The monooxygenase activity of HpaM was FAD and NADH dependent. The apparent Km values of HpaM for 5HPA and NADH were 45.4 µM and 37.8 µM, respectively. The genes hpaX, hpaD, and hpaF were found to encode 2,5DHP dioxygenase, N-formylmaleamic acid deformylase, and maleamate amidohydrolase, respectively; however, the three genes were not essential for 5HPA degradation in A. faecalis JQ135. Furthermore, the gene maiA, which encodes a maleic acid cis-trans isomerase, was essential for the metabolism of 5HPA, nicotinic acid, and picolinic acid in A. faecalis JQ135, indicating that it might be a key gene in the metabolism of pyridine derivatives. The genes and proteins identified in this study showed a novel degradation mechanism of pyridine derivatives. [ABSTRACT FROM AUTHOR]

Biosurfactant-producing bacteria were isolated from various soil and water in agricultural area of Thailand. Based on hemolytic activity, drop collapsing test, oil displacement test, as well as emulsification activity (%EA), 8 effective isolates from 234 isolates were selected. All selected isolates were tested for antimicrobial activities against plant pathogenic bacteria. It was revealed that all isolates can inhibit more than 2 tested-plant pathogenic bacteria. The crude extracts of selected isolates were tested for stability of pH, NaCl, CaCl2, MgCl2 and temperature by measuring %EA and showed stability over a broad range of these conditions. All interested isolates were identified by biochemical test and MALDI-TOF MS. The isolates were: 1 isolate Alcaligenes faecalis subsp. faecalis, 2 isolates Proteus mirabilis, and 1 isolate Providencia alcalifaciens. Overall, the strains found in this study were useful for the bioremediation of the agricultural area. [ABSTRACT FROM AUTHOR]

Curdlan has wide-ranging benefits in food and pharmaceutical industries for its unique rheological and thermal gelling properties. To analyze the cell growth and curdlan biosynthesis kinetics of Alcaligenes faecalis , the kinetic properties of the curdlan fermentation under different carbon sources conditions (maltose, sucrose, glucose and fructose) were investigated using Logistic and Luedeking-Piret equations. The results demonstrated that curdlan fermentation is partial growth-associated process. With maltose as the sole carbon source, the highest curdlan production ( P m  = 39.3 g/L), the maximum specific growth rate ( μ m  = 0.44/h) and the growth-associated rate constant (α = 2.05 g curdlan/g cell) were achieved. In contrast, the fructose was the less desired carbon source in both the cell growth and curdlan production. Further, the results demonstrated that slow-releasing glucose from maltose boosted cell growth and curdlan production. [ABSTRACT FROM AUTHOR]

Bioelectrochemical systems use microbes as catalysts for current production or consumption. Up to now only a few microbes have been demonstrated to be capable of both outward and inward extracellular electron transfer (EET) (i.e. bidirectional electron transfer). However, the mechanisms of electron exchange between microbes and extracellular solids remain uncertain. Here, we showed that Alcaligenes faecalis catalyzed an outward EET and generated electricity at a poised potential of +0.3 V vs. SHE, whereas it conducted an inward EET for autotrophic denitrification at −0.5 V vs. SHE. Both cyclic voltammetry and in situ electrochemical FTIR spectroscopy revealed that different redox components were utilized during the outward and inward EET. Electron transport inhibitor experiments indicated for the first time that complex I, II, III, and the quinone pool on the plasma membrane were involved in the bidirectional EET. Comparative proteomics showed that the protein expression profile of outward-EET biofilms differed greatly from those of inward-EET biofilms, implying that the pili and outer membrane proteins might be responsible for the interfacial outward and inward EET, respectively. These results suggest different electron transport conduits of A. faecalis biofilms could be used for bidirectional EET. [ABSTRACT FROM AUTHOR]

Penicillin G acylase (PGA) is a strategic enzyme in the production processes of beta-lactam antibiotics. High demand for β-lactam semisynthetic antibiotics explain the genetic and biochemical engineering strategies devoted towards novel ways for PGA production and application. This work presents a fermentation process for the heterologous production of PGA from Alcaligenes faecalis in Bacillus megaterium with optimization. The thermal stability from A. faecalis PGA is considerably higher than other described PGA and the recombinant enzyme is secreted to the culture medium by B. megaterium , which facilitates the separation and purification steps. Media optimization using fractional factorial design experiments was used to identify factors related to PGA activity detection in supernatant and cell lysates. The optimized medium resulted in almost 6-fold increased activity in the supernatant samples when compared with the basal medium. Maximum enzyme activity in optimized medium composition achieves values between 135 and 140 IU/ml. The results suggest a promising model for recombinant production of PGA in B. megaterium with possible extracellular expression of the active enzyme. • The Alcaligenes faecalis pac gene was cloned and expressed in Bacillus megaterium. • Screening of medium components showed that yeast extract and tryptone are significant for enzymatic PGA activity. • Enzyme activity detected in cell lysate and supernatant indicate extracellular export. • This feature may be useful to develop a faster and simpler method of purification in the future. [ABSTRACT FROM AUTHOR]