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The accumulation of nisin in the fermentation medium can reduce the process's productivity. This research studied the potential of Nymphaea alba leaf powder (NALP) as a hydrophobic biosorbent for efficient in-situ nisin adsorption from the fermentation medium by docking and experimental analysis. Molecular docking analysis showed that di-galloyl ellagic acid, a phytochemical compound found in N. alba, had the highest affinity towards nisin. Enhancements in nisin adsorption were seen following pre-treatment of NAPL with HCl and MgCl2. A logistic growth model was employed to evaluate the growth dynamics of the biosorption capacity, offering valuable insights for process scalability. Furthermore, optimization through Response Surface Methodology elucidated optimal nisin desorption conditions by Liebig's law of the minimum, which posits that the scarcest resource governs production efficiency. Fourier Transform Infrared (FTIR) spectroscopy pinpointed vital functional groups involved in biosorption. Scanning electron microscopy revealed the changing physical characteristics of the biosorbent after exposure to nisin. The findings designate NALP as a feasible adsorbent for nisin removal from the fermentation broth, thus facilitating its application in the purification of other biotechnological products based on growth and production optimization principles. [ABSTRACT FROM AUTHOR]

Background and Objectives: Recent evidences have shown that methicillin-resistant Staphylococcus aureus (MRSA) can cause severe infections and is resistant to almost all commercially available antibiotics. Therefore, screening unknown sources of biological compounds such as the Thermoactinomycetaceae family as extremophilic bacteria may be helpful to find new antimicrobial agents. Materials and Methods: Various samples were collected from different ecosystems, including desert, volcano, compost, and forest. They were cultured on Soil extract agar and Water agar. The antimicrobial activity of the isolates was evaluated using agar overlay and well diffusion methods. Members of the Thermoactinomycetaceae family were selected for further study: Their ability to grow at different temperatures, NaCl concentrations, and pH values, enzyme production ability, antimicrobial secondary screening, fractionation of their supernatants and so on. Results: According to molecular identification of active isolates against MRSA, three strains, including Laceyella sacchari UTMC 2705, Thermoactinomyces sp. UTMC 2721, and Laceyella sp. UTMC 2731, belonged to Thermoactinomycetaceae were identified. The minimum inhibitory concentrations of their extracts were tested against some pathogenic bacteria, showing their antimicrobial activity with a broad spectrum. The results of TLC bioautography of the extracts showed that the most active fractions were semi-polar. Also, the results of HPLC analysis showed the existence of several UV-active compounds in their extracts. Conclusion: The present study highlighted the importance and potential of Thermoactinomycetaceae members as a lessknown source of antibiotics against pathogenic bacteria. [ABSTRACT FROM AUTHOR]

In the present study, 40 actinobacterial isolates were obtained from the roots of a desert plant, Pteropyrum olivieri and tested for extracellular hydrolytic enzyme activities, hydrogen cyanide, and siderophore production. Based on these activities, three isolates designated UTMC 2482, UTMC 2483, and UTMC 3136 were selected with an aim of developing bio-fertilizing agent to improve the growth of sunflower plants under normal conditions. The selected isolates showed 98.2, 98.4, and 100% similarities in the 16S rRNA gene sequences to Streptomyces chromofuscus, Streptomyces ambofaciens, and Streptomyces gardneri, respectively. These isolates exhibited indole acetic acid production while UTMC 2483 was found to produce 1-aminocyclopropane-1-carboxylate deaminase, as well. Sunflower seeds soaked in the bacterial spore suspensions increased the tolerance of sunflower seedlings to the stresses of salinity and water deficiency up to 270 mM of NaCl and − 2Mpa of PEG6000, respectively. Under normal conditions, inoculation with individual isolates and their consortia enhanced the yield (plant length, weight, and flower diameter) and biochemical contents (i.e. chlorophyll, protein, and oil) up to 5.3, 1.7, and 2.4 times higher than that of un-inoculated plants, significantly (p < 0.05) in greenhouse and field experiments. This is the first study demonstrating that endophytic actinobacteria from the desert plant, P. olivieri, have profound bio-fertilizing effects on the growth of sunflower. [ABSTRACT FROM AUTHOR]

Background and Objectives: Streptomyces tendae is one of the most prolific actinobacteria with a wide range of biotechnological applications. Genomic data can help in better understanding and exploration of important microorganisms, however, there is a few genomic information available for this species. Materials and Methods: Molecular identification, pH and salt tolerance of an actinobacterium, designated Streptomyces tendae UTMC 3329, isolated from a tea field soil were done. Also, genomic DNA was extracted and sequenced using Illumina platform with MPS (massively parallel sequencing) Illumina technology. Gene annotation and bioinformatic analysis were done using appropriate software and servers. Results: The draft genome is ~8.7 megabase pairs, containing 7557 predicted coding sequences. The strain was able to grow at pH 5-12 and 0-10% NaCl. The maximum growth rate of the bacterium was obtained at pH 7. The gene clusters involved in central carbon metabolism, phosphate regulation, transport system, stress responses were revealed. It was shown the presence of gene clusters of polyketides, ribosomally and non-ribosomally synthesized peptides. Various genes were found in xenobiotic degradation pathways and heavy metal resistance. Conclusion: The current genomic information which reveals biological features, as well as the biotechnological potential of this acid and alkaline tolerant actinobacterium, can be implemented for further research on the species. [ABSTRACT FROM AUTHOR]

Transcription is of the most crucial steps of gene expression in bacteria, whose regulation guarantees the bacteria's ability to adapt to varying environmental conditions. Discovering the molecular basis and genomic principles of the transcriptional regulation is thus one of the most important tasks in cellular and molecular biology. Here, a comprehensive phylogenetic footprinting framework was implemented to predict maximal regulons of Lactococcus lactis subsp. lactis IO-1, a lactic acid bacterium known for its high potentials in nisin Z production as well as efficient xylose consumption which have made it a promising biotechnological strain. A total set of 321 regulons covering more than 90% of all the bacterium's operons have been elucidated and validated according to available data. Multiple novel biologically-relevant members were introduced amongst which arsC, mtlA and mtl operon for BusR, MtlR and XylR regulons can be named, respectively. Moreover, the effect of riboflavin on nisin biosynthesis was assessed in vitro and a negative correlation was observed. It is believed that understandings from such networks not only can be useful for studying transcriptional regulatory potentials of the target organism but also can be implemented in biotechnology to rationally design favorable production conditions. [ABSTRACT FROM AUTHOR]

Different carbon-based nanostructures were used to investigate direct electron transfer (DET) of TetX2 monooxygenase (TetX2), and an enzyme-based biosensor for sensitive determination of tetracycline (TC) also fabricated. A polyethyleneimine (PEI) with positive charge groups was used for immobilization of TetX2 on modified glassy carbon electrodes. Cyclic voltammetry (CV) was employed to study the electrochemical characteristics of the immobilized enzyme and the performance of the proposed biosensor. Amongst multiple carbon-modified electrodes, nano-porous glassy carbon electrode (NPGCE) was selected because of its amplified signal response for flavin adenine dinucleotide (FAD) and superior electrocatalytic behavior toward oxygen reduction. The cyclic voltammogram of PEI/TetX2/NPGCE showed two couple of well-defined and quasi-reversible redox peaks of FAD, consistent with the realization of DET. The prepared electrode was then successfully introduced as a biosensing interface based on the oxygen reduction peak current, resulting in a linear range response from 0.5 to 5 μM with a good detection limit of 18 nM. The as-fabricated electrode demonstrates a fast response and excellent stability for the detection of TC. The results indicate that this simple, rapid, eco-friendly and economic strategy of PEI/TetX2/NPGCE preparation has potential for the fabrication of an enzyme-based biosensor for the practical detection of TC in food products. Unlabelled Image • Bacterial TetX2 monooxygenase was used for electrochemical sensing of tetracycline. • TetX2 immobilization on modified electrodes was done by polyethylenimine. • Nano-porous glassy carbon electrode enhanced the direct electrochemistry of TetX2. • High selectivity and sensitivity were achieved with a low detection limit of 18 nM. [ABSTRACT FROM AUTHOR]

Thrombotic disorders increase the risk of cardiovascular/cerebrovascular complications and represent a major health problem worldwide. Anticoagulants are extensively used in treatment of these disorders. Vitamin K antagonists, like Warfarin, are frequently used in medication. Vascular calcification (VC) is a significant side-effect of vitamin K antagonists especially Warfarin. There is an urgent need to find natural, efficient, non-toxic, and cost effective anticoagulants without dangerous side-effect like VC. In the present study, we evaluated the potential of thirteen fermentation broth extracts of actinobacteria (FBEA) (200 µg mL-1) to prolong whole blood prothrombin time (PT)/international normalized ratio (INR) and activated partial thromboplastin time (APTT). The fractions of the most effective FBEA were further investigated for their inhibitory effect on VC. The results showed PT/INR of the healthy blood samples was sensitive to the presence of five FBEA. Their INR index fell in the 1.2 to 8.6 range and six FBEA prolonged both PT/INR and APTT parameters (1.7-5 INR, and 46-59 s for APTT). The fractions of Kribbella sp. UTMC 267 FBE (200 µg mL-1), as the most efficient FBE, only inhibited intrinsic and common pathways of coagulation (APTT). Under calcification condition, Kribbella sp. UTMC 267 fractions (20 µg mL-1) showed significant inhibitory effect on VC in alizarin red staining (13.3-76%) and alkaline phosphatase activity of VSMCs (33-62%). They also inhibited osteopontin mRNA expression in treated vascular smooth muscle cells (VSMCs) under that situation. So, we can introduce Kribbella sp. UTMC 267 FBE as a good candidate for more investigation on thrombotic medication. [ABSTRACT FROM AUTHOR]

Polysaccharides could be used as biodegradable and biocompatible polymers for scaffolds and carriers matrix. Numerous algal, fungi and herbal polysaccharides can attenuate degradation of skin matrix by the inhibition of elastase, collagenase and matrix metalloproteinases (MMPs). In this study, we investigate anti-elastase and anti-collagenase potential of Lactobacilli exopolysaccharides (LEPS) on normal human fibroblast. Among 60 Lactobacilli isolated from herbal plants and dairy products, selected LEPS showed high anti-collagenase (up to 100%), anti-elastase (up to 87%) and antioxidant activity (up to 60%). Most of them had no cytotoxicity effect on fibroblast, and some of them promote cell proliferation (up to 10%). In scratch assay, all the investigated EPSs stimulated wound healing process in fibroblast (up to 99%). MMP1, MMP2, MMP3, MMP9 and MMP10 were down-regulated significantly and TIMP1 and TIMP2 were up-regulated slightly in LEPS of B9-1 from L. casei with high anti-collagenase and anti-elastase activity; however, no meaningful alteration was observed in MMPs expression level for LEPS of P35 from L. plantarum with low anti-collagenase and anti-elastase activity. By consideration of high anti-collagenase, anti-elastase, antioxidant activity and wound healing of LEPS, they could be considered as good candidate of skin anti-aging agents for tissue engineering and skin regeneration scaffolds. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Lantibiotics can be accurately predicted by their sequence via machine learning. • SVM and SMO algorithms generated the most accurate lantibiotic predictor models. • Feature selection and sequence logo revealed significant distinctions in lantibiotics sequences. • The existence of leucine in position 10 from C-termini of most lantibiotics is a meaningful difference. • Glutamic acid residue frequency is higher in lantibiotics. • Lysin/Arginine residues are mostly distributed in C-termini. Abstract Lantibiotics, an important group of ribosomally synthesized peptides, represent an important arsenal of novel promising antimicrobials showing high potency in fighting against the prevalence of antibiotic resistance among microbial pathogens. However, due to the lack of high throughput strategies for the isolation and identification of these compounds, our information regarding their structure and especially sequence-based properties is far from complete. Therefore, in the present study, a comprehensive sequence-based analysis of these peptides was performed with the help of machine learning approach together with a feature selection technique. Meanwhile, an attempt to develop an accurate computational model for prediction of lantibiotics was made via constructing two datasets of 280 and 190 lantibiotic and non-lantibiotic antimicrobial peptide sequences, respectively. Based on the conducted approach and as a result of our search for a subset of relevant features of lantibiotics, particular types of sequenced-based features were observed to be preferred in lantibiotics, the knowledge-based implementation of which can be used as strategies for lantibiotic bioengineering purposes. Moreover, a SMO-based classifier was developed for the prediction of lantibiotics with the accuracy and specificity values of 88.5% and 94%, respectively which shows the great potential of the developed algorithm for the prediction of lantibiotcs. Conclusively, the accurate predictor algorithm as well as the identified sequence-based distinctiveness properties of lantibiotics can give valuable information in both the fields of lantibiotic discovery and bioengineering. [ABSTRACT FROM AUTHOR]

New methods to determine antimicrobial susceptibility of bacterial pathogens especially the minimum inhibitory concentration (MIC) of antibiotics have great importance in pharmaceutical industry and treatment procedures. In the present study, the MIC of several antibiotics was determined against some pathogenic bacteria using macrodilution test. In order to accelerate and increase the efficiency of culture-based method to determine antimicrobial susceptibility, the possible relationship between the changes in some physico-chemical parameters including conductivity, electrical potential difference (EPD), pH and total number of test strains was investigated during the logarithmic phase of bacterial growth in presence of antibiotics. The correlation between changes in these physico-chemical parameters and growth of bacteria was statistically evaluated using linear and non-linear regression models. Finally, the calculated MIC values in new proposed method were compared with the MIC derived from macrodilution test. The results represent significant association between the changes in EPD and pH values and growth of the tested bacteria during the exponential phase of bacterial growth. It has been assumed that the proliferation of bacteria can cause the significant changes in EPD values. The MIC values in both conventional and new method were consistent to each other. In conclusion, cost and time effective antimicrobial susceptibility test can be developed based on monitoring the changes in EPD values. The new proposed strategy also can be used in high throughput screening of biocompounds for their antimicrobial activity in a relatively shorter time (6-8 h) in comparison with the conventional methods. [ABSTRACT FROM AUTHOR]

Polyunsaturated fatty acids (PUFAs) are essential to human health and can be produced by enzymatic esterification. Actinomadura sediminis UTMC 2870 isolated from oil-contaminated soil contained a lipase that was stable at varying pH and in various solvents, salts, and chemicals. This lipase exhibited high efficiency for omega-3 (n-3), and its production was optimized using a response surface method. Acylglycerols (AGs) rich in n-3 were produced by extraction of the free fatty acids (FFAs) from flaxseed oil, concentration of PUFAs, and enzymatic esterification by the Celite-immobilized lipase. The resulting product contained 50% (w/w) PUFAs, including 42% (w/w) α-linolenic and 9.7% (w/w) linoleic acid. The n-6/n-3 ratio in the product was 0.24, which differed markedly from the high values for this ratio in seed oils. Therefore, the A. sediminis lipase appears to be a good candidate enzyme for ester synthesis and especially for production of n-3–rich AGs for food industries. [ABSTRACT FROM AUTHOR]

Polysaccharides could be used as biodegradable and biocompatible polymers for scaffolds and carriers matrix. Numerous algal, fungi and herbal polysaccharides can attenuate degradation of skin matrix by the inhibition of elastase, collagenase and matrix metalloproteinases (MMPs). In this study, we investigate anti-elastase and anti-collagenase potential of Lactobacilli exopolysaccharides (LEPS) on normal human fibroblast. Among 60 Lactobacilli isolated from herbal plants and dairy products, selected LEPS showed high anti-collagenase (up to 100%), anti-elastase (up to 87%) and antioxidant activity (up to 60%). Most of them had no cytotoxicity effect on fibroblast, and some of them promote cell proliferation (up to 10%). In scratch assay, all the investigated EPSs stimulated wound healing process in fibroblast (up to 99%). MMP1, MMP2, MMP3, MMP9 and MMP10 were down-regulated significantly and TIMP1 and TIMP2 were up-regulated slightly in LEPS of B9-1 from L. casei with high anti-collagenase and anti-elastase activity; however, no meaningful alteration was observed in MMPs expression level for LEPS of P35 from L. plantarum with low anti-collagenase and anti-elastase activity. By consideration of high anti-collagenase, anti-elastase, antioxidant activity and wound healing of LEPS, they could be considered as good candidate of skin anti-aging agents for tissue engineering and skin regeneration scaffolds. [ABSTRACT FROM AUTHOR]

Nisin is a safe, approved and commercial bacteriocin that is produced by Lactococcus lactis subsp. lactis. Since lactate accumulation in fermentation medium reduces L. lactis growth and nisin production, Yarrowia lipolytica , a lactate consuming yeast and L. lactis subsp. lactis , were simultaneously cultured in a molasses based medium. Y. lipolytica is not able to consume sucrose as carbon source, but rather consumes lactate and hence decrease lactic acid titer by 10% in the medium. Lactic acid consumption, 15% increased pH value and stimulated L. lactis growth. In the mixed culture, nisin production and L. lactis growth were 50% and 49% higher than that of pure culture, respectively. Also the results showed that specific growth rate of L. lactis increased 4 times more than that of the pure culture. [ABSTRACT FROM AUTHOR]

Introduction: Nep1 is a natural bio-herbicide protein which has an effective necrosis stimulant in dicotyledonous weeds. This protein was first purified in 1995 form fermentation broth of Fusarium oxysporum. Materials and methods: In this study, the nep1gene was isolated form F. oxysporum, after removal of signal peptide from the beginning of the gene; final pET16b-nep1 construct was cloned and transformed into E. coli BL21 (DE3). The recombinant Nep1 was produced in E. coli. Recombinant protein was purified, diluted and prepared for biological assay on weed. Results: Two ml of recombinant Nep1 with 60 μg/ml final concentrations was sprayed on Convolvulus arvensis. Our results showed necrosis and chlorosis symptoms were started on the plant leaves after 2 days, also significant necrosis on the leaves of C. arvensis was seen after 5 days. No necrosis lesion was seen in the negative control plants that sprayed only with buffer and denatured recombinant Nep1 in 100 °C for 15 min. Discussion and conclusion: Our results introduced recombinant Nep1 as a biological potent agent for biocontrol of C. arvensis. [ABSTRACT FROM AUTHOR]

Background and Objective: Due to the evolution of multidrug-resistant strains, screening of natural resources, especially actinomycetes, for new therapeutic agents discovery has become the interests of researchers. In this study, molecular, chemical and biological screening of soil actinomycetes was carried out in order to search for peptide-producing actinomycetes. Materials and Methods: 60 actinomycetes were isolated from soils of Iran. The isolates were subjected to molecular screening for detection NRPS (non-ribosomal peptide synthetases) gene. Phylogenic identification of NRPS containing isolates was performed. Chemical screening of the crude extracts was performed using chlorine o-dianisidine as peptide detector reagent and bioactivity of peptide producing strains was determined by antimicrobial bioassay. High pressure liquid chromatography- mass spectrometry (HPLC-MS) with UV-visible spectroscopy was performed for detection of the metabolite diversity in selected strain. Results: Amplified NRPS adenylation gene (700 bp) was detected among 30 strains. Phylogenic identification of these isolates showed presence of rare actinomycetes genera among the isolates and 10 out of 30 strains were subjected to chemical screening. Nocardia sp. UTMC 751 showed antimicrobial activity against bacterial and fungal test pathogens. HPLC-MS and UV-visible spectroscopy results from the crude extract showed that this strain has probably the ability to produce new metabolites. Conclusion: By application of a combined approach, including molecular, chemical and bioactivity analysis, a promising strain of Nocardia sp. UTMC 751 was obtained. This strain had significant activity against Staphylococcus aureus and Pseudomonas aeruginosa. Strain Nocardia sp. UTMC 751 produce five unknown and most probably new metabolites with molecular weights of 274.2, 390.3, 415.3, 598.4 and 772.5. This strain had showed 99% similarity to Nocardia ignorata DSM 44496 T. [ABSTRACT FROM AUTHOR]

Plant growth promoting (PGP) bacteria are involved in various interactions known to affect plant fitness and soil quality, thereby increasing the productivity of agriculture and stability of soil. Although the potential of actinobacteria in antibiotic production is well-investigated, their capacity to enhance plant growth is not fully surveyed. Due to the following justifications, PGP actinobacteria (PGPA) can be considered as a more promising taxonomical group of PGP bacteria: (1) high numbers of actinobacteria per gram of soil and their filamentous nature, (2) genome dedicated to the secondary metabolite production (~5 to 10 %) is distinctively more than that of other bacteria and (3) number of plant growth promoter genera reported from actinobacteria is 1.3 times higher than that of other bacteria. Mechanisms by which PGPA contribute to the plant growth by association are: (a) enhancing nutrients availability, (b) regulation of plant metabolism, (c) decreasing environmental stress, (d) control of phytopathogens and (e) improvement of soil texture. Taxonomical and chemical diversity of PGPA and their biotechnological application along with their associated challenges are summarized in this paper. [ABSTRACT FROM AUTHOR]

More than 70 species of halotolerant and halophilic actinomycetes belonging to at least 24 genera have been validly described. Halophilic actinomycetes are a less explored source of actinomycetes for discovery of novel bioactive secondary metabolites. Degradation of aliphatic and aromatic organic compounds, detoxification of pollutants, production of new enzymes and other metabolites such as antibiotics, compatible solutes and polymers are other potential industrial applications of halophilic and halotolerant actinomycetes. Especially new bioactive secondary metabolites that are derived from only a small fraction of the investigated halophilic actinomycetes, mainly from marine habitats, have revealed the huge capacity of this physiological group in production of new bioactive chemical entities. Combined high metabolic capacities of actinomycetes and unique features related to extremophilic nature of the halophilic actinomycetes have conferred on them an influential role for future biotechnological applications. [ABSTRACT FROM AUTHOR]

Actinomycetes isolated from Iran soil habitats were tested for the capacity to produce compounds which can protect neurons from cell death generated by oxidative stress in NT2 neurons. Confirmation of our initial hit was accomplished via the determination of amyloid β level using the enzyme-linked immunosorbent assay test. The most interesting amyloid β formation inhibitor discovered in our study was a secondary metabolite which was produced by strain HM45. This bioactive strain was identified as a strain of Streptomyces antibioticus DSM 40234 using polyphasic approach. The strain HM45 was deposited in Deutsche Sammlung von Mikroorganismen und Zellkulturen as S. antibioticus DSM 41955 and University of Tehran Microorganisms Sollection as S. antibioticus UTMC 00105. This work is the first report on efficiency of an actinomycete metabolite in prohibition of neurons death caused by amyloid β formation. [ABSTRACT FROM AUTHOR]

Biofertilizers based on plant growth-promoting actinobacteria are used as potential alternatives to chemical fertilizers for sustainable agricultural systems. However, successful application of PGPA to agricultural land is challenging. The present study was an attempt to develop and evaluate the effect of a low-cost biofertilizer named NCTS (nanoclay-treated-Streptomyces) based on Streptomyces sp. UTMC 3136 spores amalgamated in a hybrid material of nanoclay Na-montmorillonite K10-glycerol-water substrate. In addition, the effect of NCTS on sunflower growth was investigated. In vivo tests showed a statistically significant increase in the agronomic characteristics of sunflowers treated with NCTS. Characterization of NCTS by FTIR, Raman spectroscopy, and scanning electron microscopy testified to the structural alignment and good adhesion of NCTS components. The viability of NCTS was 100% after 72 h of storage at 4 °C. Overall, the present study attempted to validate the efficacy of the formulation of Streptomyces sp. UTMC 3136 in nanoclay for growth improvement of sunflower. It was the first study to show the administration of PGPA in combination with nanomaterials as a growth enhancing biofertilization agent for sunflower. [ABSTRACT FROM AUTHOR]

In the two-component system of NisRK from Lactococcus lactis, the production of nisin is affected by transmembrane NisK and activation of intracellular NisR. The transcription of nisin structural genes can be induced by derivatives of nisin. NisR activation leads to the activation of nisA/Z transcription, which encodes the nisin maturation machinery, nisin regulation and activation of the nisFEG operon to confer immunity. The aim of this study was to express the Lactococcus lactis histidine phosphokinase NisK and response regulator NisR in E. coli, and to perform activity assays and in silico analysis. In silico methods were applied to study the properties and structures of the NisK and NisR proteins, including prediction of physicochemical characteristics, secondary and tertiary structure, stability and ligand-receptor interactions.pET32a and pET28a vectors containing synthetic nisK and nisR genes were transformed into E. coli followed by IPTG induction. SDS-PAGE and western blotting methods were applied to confirm the presence and identity of the amplified proteins. Following purification, the proteins were dialyzed and then prepared for activity assay. The CAI index showed that the genes was compatible with the E. coli host and that the proteins have effective expression. Also, the mRNA prediction results suggest that there is enough mRNA stability for efficient translation in the new host. NisK and NisR recombinant proteins were expressed in E. coli with half - lives of around 10 h and were confirmed with molecular weights of 27 kDa and 69 kDa, respectively, by SDS-PAGE and western blotting. The secondary structure of the recombinant proteins as predicted by circular dichroism spectroscopy was similar to the in silico protein structures. Activity assay of recombinant NisK was performed by measuring the amount of consumed ATP according to the light produced by luciferase. Because NisK and NisR have a direct impact on each other, they have an essential role in increasing the production of nisin and they can be used in different research fields. Our results demonstrated that recombinant proteins NisK and NisR preserved their structure and function after expression. [ABSTRACT FROM AUTHOR]

Abstract: Biosurfactants are structurally a diverse group of surface‐active molecules widely used for various purposes in industry. In this study, among 120 fungal isolates, M‐06 was selected as a superior biosurfactant producer, based on different standard methods, and was identified as Mucor circinelloides on the basis of its nucleotide sequence of the internal transcribed spacer (ITS) gene. M. circinelloides reduced the surface tension to 26 mN/m and its EI24 index was determined to be 66.6%. The produced biosurfactant exhibited a high degree of stability at a high temperature (121°C), salinity (40 g/L), and acidic pH (2–8). The fermentation broth's ability to recover oil from contaminated sand was 2 and 1.8 times higher than those of water and Tween 80, respectively. The ability of biosurfactant to emulsify crude oil in the sea and fresh water was 64.9 and 48% respectively. This strain could remove 87.6% of crude oil in the Minimal Salt Medium (MSM) crude oil as the sole carbon source. The results from a primary chemical characterization of crude biosurfactant suggest that it is of a glycolipid nature. The strain and its biosurfactant could be used as a potent candidate in bioremediation of oil‐contaminated water, soil, and for oil recovery processes. [ABSTRACT FROM AUTHOR]

Biosurfactants are biocompatible surface active agents which many microorganisms produce. This study investigated the production of biosurfactants by Mucor circinelloides. The effects of different factors on biosurfactant production, including carbon sources and concentrations, nitrogen sources and iron (II) concentration, were studied and the optimum condition determined. Finally, the strain's ability to remove the crude oil and its relationship with biosurfactant production was evaluated. The results showed that M. circinelloides could reduce the surface tension of the culture medium to 26.6 mN/m and create a clear zone of 12.9 cm diameter in an oil-spreading test. The maximum surface tension reduction was recorded 3 days after incubation. The optimum condition for biosurfactant production was achieved in the presence of 8% waste frying oil as a carbon source, 2 g/L yeast extract as a nitrogen source and 0.01 mM FeSO4. M. circinelloides could consume 8% waste frying oil in 5 days of incubation and 87.6% crude oil in 12 days of incubation. A direct correlation was observed between oil degradation and surface tension reduction in the first 3 days of fungal growth. The results showed that the waste frying oil could be recommended as an inexpensive oily waste substance for biosurfactant production and M. circinelloides could have the potential to treat waste frying oil. According to the results, the produced crude biosurfactant or fungal strain could be directly used for the mycoremediation of crude oil contamination in oil fields. [ABSTRACT FROM AUTHOR]

Environmental pollution caused by petroleum compounds has become a global concern. The aim of this study was to evaluate the indigenous fungal isolates in Iran for biodegradation of crude oil pollutants. In order to isolate fungal strains, the soil samples were enriched in minimal salts medium (MSM) with 1% crude oil and then the crude oil degradation was measured by total petroleum hydrocarbon (TPH) assay. The degradation of hydrocarbons compounds was also analysed by FT-IR and HPLC, and the activity of peroxidase enzyme and biosurfactant production were also measured. We isolated 40 fungal strains and selected the isolate G-05 with 70% degradation ability of petroleum hydrocarbons as a premium isolate after 15 days. Residual crude oil analysis with FT-IR spectrophotometry and HPLC showed that G-05 is able to degrade 90 and 100% of aliphatic compounds and some polycyclic aromatic hydrocarbons (PAH), respectively. Evaluation of enzymatic activity showed that this isolate can produce 4 U L of Laccase enzyme for oil removal; it is capable of producing biosurfactant and reducing the surface tension of the medium to 25.95 ± 0.1 m Nm. This strain was identified as a member of Trematophoma genus and the obtained results showed that this strain is a highly potent strain in bioremediation of soils contaminated by crude oil. Graphical Abstract: [ABSTRACT FROM AUTHOR]

Recently, there has been a growing demand to develop portable devices for the fast detection of contaminants in food safety, healthcare, and environmental fields. Herein, two biosensing methods were designed by the use of nicotinamide adenine dinucleotide phosphate (NAD(P)H)-dependent TetX2 enzyme activity and thionine as an excellent electrochemical and colorimetric mediator/probe to monitor tetracycline (TC) in milk. The nanoporous glassy carbon electrode (NPGCE) modified with polythionine was first prepared by electrochemically and then TetX2 was immobilized onto the NPGCE using polyethyleneimine. The prepared biosensor provided a high electrocatalytic response toward NAD(P)H by significantly reducing its overpotential. The proposed biosensor exhibited a detection limit of 40 nM with a linear range of 0.1-0.8 µM for TC determination. Besides, the thionine probe was used to develop a novel colorimetric assay using a simple enzymatic color reaction within a few minutes. The limit of detection for TC was experimentally achieved as 60 nM, which was lower than the safety levels established by the World Health Organization (225 nM). The correlation between change in the color of the solution and the concentration of TC was used for quality control of milk samples, as confirmed by the standard high-performance liquid chromatography method. The results show the great potential of the proposed assays as portable instruments for on-site TC measurements. [ABSTRACT FROM AUTHOR]

Abstract: Two new N-methylated cyclopeptides, persipeptide A (1) and B (2), have been isolated from Streptomyces sp. UTMC1154. Their structures were established using 1D and 2D NMR experiments. 2D TOCSY experiments were applied to identify the amino acid residues, while HMBC correlations were used to determine their sequence. According to Marfey’s method, all amino acids had the l-configuration. The two cyclic peptides had the same ring size and amino acid composition, but differed in their sequence; they did not show activity against the tested bacteria, fungi and algae. Molecular identification experiments placed the strain in the genus Streptomyces closely related to Streptomyces coerulescens DSM40146T (99.45%) and Streptomyces varsoviensis DSM40346T (99.25%). [Copyright &y& Elsevier]

[Display omitted] • L. lactis NCDO 2118 metabolic model can precisely predict bacterium physiology. • GABA biosynthesis can provide more energy for bacterium due to consumption of cytosolic protons. • Higher glutamate uptake rates result in higher GABA production. • Model guided analysis revealed succinate biosynthesis pathway of L. lactis. • In silico elimination of glycine and arginine exchange reactions elevate succinate production rate by 137.9 %. Non-dairy Lactococcus lactis subsp. lactis NCDO 2118 is well known for its Gamma-aminobutyric acid (GABA) producing capability. In this study, genome-scale metabolic model of Lactococcus lactis subsp. lactis NCDO 2118 covering 62 pathways and consisting of 1084 genes, 965 reactions, and 864 metabolites was reconstructed. The validation process was performed using various types of physiological data. Validated model could predict growth rates on different defined media similar to the experimental data. Also, flux distribution through metabolic pathways was simulated by the resultant model, which was similar to experimental flux distribution data. The final model named i OA1084. After model validation, GABA production under normal and high glutamate uptake rates was investigated using flux balance analysis (FBA). i OA1084 predicts that an increase in glutamate uptake rate results in a high GABA production rate, which is a proton consuming reaction. This depletion of cytosolic proton might result in changing ATP synthase reaction from ATP consumption to ATP production. Also, i OA1084 showed an enhanced succinate production rate in aerobic conditions. Further in silico analysis showed that bacterium might use a different pathway from the citric acid cycle to produce succinate. i OA1084 suggested that knocking out of arginine and glycine exchange reactions could result in more succinate production. [ABSTRACT FROM AUTHOR]

• SBA-15 was doped by oleic acid as highly selective and efficient hydrophobic support. • SBA-15@oleate@lipase was developed based on interfacial activation mechanism. • The maximum immobilization yield (80%) was attained at 200 µg ml−1 of the protein. • Biodiesel production with 85%±3.2 conversion was performed by the heterogeneous biocatalyst. • The heterogeneous biocatalyst showed a high capability to produce methyl palmitoleate. Rising world demand coupled with diminishing supply of fossil fuels and petroleum products have led to look for alternative renewable and clean fuels such as biodiesel. The production of biodiesel can be facilitated with suitable biocatalysts. In the present study, a mesoporous silica of SBA-15 modified with oleic acid and a solvent tolerant lipase from Actinomadura sediminis (SBA-15@oleate@lipase) was designed as the heterogeneous biocatalyst with maximum activity by a protein loading of 32.0 mg per gram of the support. The maximum immobilization efficiency (68%) and yield (80%) were also obtained at 200 µg ml−1 of the protein with reaction time of 60 min. The enzymatic trans-esterification reaction was catalyzed for converting oil of the cyanobacterium Synechococcus elongatus into biodiesel with an 85% ± 3.2 yield under optimized conditions. The designed heterogeneous biocatalyst revealed a high efficiency towards palmitoleic acid (C16:1) in the microalgal oil that is one of the best fatty acids to produce a high-quality biodiesel. This work also highlights the simultaneous combination of purification and immobilization of the bacterial lipase by interfacial activation mechanism, to the synthesis of a solid biocatalyst for production of a cyanobacterium-based biodiesel. [ABSTRACT FROM AUTHOR]

Co-v-culture (co-cultivations of physically separated microbes that only interact through the air) systems were designed to investigate the effects of microbial volatile organic compounds (mVOCs) from about 20 different microbes, on a medicinal fungus, Ganoderma lucidum. For more accuracy in co-cultivations, a novel synchronized cultivation approach was tested for culturing G. lucidum. The hyphal growth of G. lucidum and the content of its ganoderic acids (GAs) were measured. In almost all of the co-v-cultures, there was an inhibiting effect on hyphal growth and a promoting effect on GAs contents. In inducing GAs production, Bacillus cereus PTCC 1247 and Pseudomonas aeruginosa UTMC 1404 were the most effective ones, as, compared to control cultures, GAs content increased 2.8 fold. Comparing different co-v-cultivations demonstrated that the concentrations of mVOCs, oxygen, and carbon dioxide were the main players in co-v-cultures. No correlation was found between hyphal growth and GAs production. Strains of the same species imposed totally different effects on hyphal growth or GAs production. This study has investigated the effects of mVOCs on G. lucidum for the first time. Moreover, it suggests that co-v-cultivation may be a promising biotechnological approach to improve the production in G. lucidum. [ABSTRACT FROM AUTHOR]

In a new approach, a copper(II) tetraaza macrocyclic complex (CuTAM) was covalently bonded on modified multi-walled carbon nanotubes (MWCNTs). To achieve this purpose, MWCNTs were converted to MWCNT-COCl and then reacted to NH groups of TAM ligand. The prepared material was characterized by Fourier Transform Infrared (FT-IR), X-ray diffraction (XRD), Raman spectroscopy, thermal gravimetric analysis (TGA), and FESEM (field emission scanning electron microscopy). FT-IR and TGA demonstrated the presence of the organic moieties, and XRD proved that the structure of MWCNTs remained intact during the three modification steps. An increase in the I D / I G ratio in Raman spectra confirmed the surface modifications. Finally, the samples were subjected to an antibacterial assessment to compare their biological activity. The antibacterial test showed that the grafted complex on the surface of the nanotube (MWCNT-CO-CuTAM) has higher antibacterial activity against Bacillus subtilis ATCC 6633 than the MWCNT-COOH and CuTAM with 1000 and 2000 μg/mL. [ABSTRACT FROM AUTHOR]

In this study 97 soil samples from different soil ecosystems were collected. The initial screening was performed on modified glycerol arginine agar (MGAA) to isolate common actinomycetes and on modified MGA-SE (MMGA-SE) to isolate rare actinomycetes. Sixty-seven isolates potentially producing extracellular phytate-degrading activity were identified. The potential to dephosphorylate phytate was confirmed in liquid culture for 46.3 % of the isolates. 12 strains were selected for a direct determination of their phytate-degrading capacity. The results highlighted that the selected isolates produced extracellular phytate-degrading activity; however their capacity in InsP degradation was different. In addition the fermentation medium had an effect on the extent of phytate degradation. Some enzymatic properties of the phytases from isolate No. 43 and isolate No. 63 were determined after obtaining phytase-enriched samples. The enzymes had maximum phytate-degrading capability at 55 °C and pH 5 (isolate No. 43) and 37 °C and pH 7 (isolates No. 63), respectively. Due to their properties, the phytase of isolate No. 43 behaves like a histidine acid phytase, whereas the phytase of No. 63 showed similar enzymatic properties to the phytase of lily. To our knowledge, the results from this study demonstrated for the first time that actinomycetes produce extracellular phytate-degrading activity. By 16SrRNA sequencing, the more closely studied phytase producers were identified a s Streptomyces sp. Isolate No. 43 showed 98 % identity to Streptomyces alboniger and S. venezuelae, while isolate No. 63 exhibited 98 % sequence identity to S. ambofaciens and S. lienomycini. [ABSTRACT FROM AUTHOR]

In this study, indigenous cyanogenic bacterial strains were isolated on nutrient, minimal salt, and soil extract media at various culture conditions from two distinct landfills of e-waste, Iran. Based on their cyanide formation profiles, five most potent isolates were selected for optimization and to this end, the influence of the most effective factors on cyanide production including pH, glycine concentration and temperature were assessed using one-factor at a time method (OFAT). Initial pH of 7, glycine concentration of 2 g/L and temperature of 30 °C were obtained as optimal conditions for most of the isolates. Additionally, two bioleaching processes were applied for each bacteria to detect the effect of optimal conditions on bioleaching and to assay their potential in the mobilization of copper. Under optimal conditions and pulp density of 1 g/L, copper recoveries were recorded as 96.73%, 82.49%, 81.17%, 41.72%, and 31.52% by S22, N13, N37, N23, and N41 respectively during 10 days which is approximately 1.5–5 times higher than the recovery obtained without optimization. During the optimization and the bioleaching process, the pH fluctuation of the flasks was monitored which validated the activity of the microorganisms. Image 1 • 16 cyanogenic bacterial strains were isolated from two e-waste landfill soil samples. • Most effective factors on cyanide production were optimized for 5 potent isolates. • For most isolates pH 7, glycine addition 2 g/L and temperature 30 °C were optimal. • The Cu recovery was enhanced up to 1.5–5 times higher under optimal conditions. • Copper was recovered more than 96% using indigenous cyanogenic isolates. [ABSTRACT FROM AUTHOR]

• Cellulose produced by Gluconoacetobacter xylinum does not have antibacterial properties. • CQD-TiO 2 nanoparticles have antibacterial properties against Staphylococcus aureus bacteria. • BC/CQD-TiO 2 nanocomposite can be used as an antibacterial wound healing bandage. • Scratch test indicated that the BC/CQD-TiO 2 was effective in wound healing. Antibacterial dressing can prevent the occurrence of many infections of wounds. Bacterial cellulose (BC) has the ability to carry and transfer the medicine to achieve a wound healing bandage. In this study, Carbon Quantum Dots-Titanium dioxide (CQD-TiO 2) nanoparticles (NP) were added to BC as antibacterial agents. FTIR Spectroscopy illuminated that NPs were well-bonded to BC. Interestingly, MIC test proved that BC/CQD-TiO 2 nanostructure (NS) has anti-bacterial properties against Staphylococcus aureus. The findings indicated that, CQD-TiO 2 NPs have stronger antibacterial properties with better tensile strength compared to CQD NPs, in a concentration-dependent manner. Toxicity of CQD-TiO 2 NPs on human L929 fibroblast cells was also evaluated. Most importantly, the results of the scratch test indicated that the NS was effective in wound healing in L929 cells. The approach in this study may provide an alternative to make an antibacterial wound dressing to achieve an effective drug-based bandage. [ABSTRACT FROM AUTHOR]