Bacterial cellulose has drawn the attention for its unique properties and applications including;... more Bacterial cellulose has drawn the attention for its unique properties and applications including; medicine, pharmacy, food, agricultural, textile and electronics. The present study focused on the production of bacterial cellulose nanofibrils (BCNF) from black tea as cost effective alternative medium in addition to study the effect of gamma radiation on BCNF properties. A symbiotic culture of bacteria and yeast (SCOBY) were isolated from commercial Kombucha beverage and used for production of BCNF on Hestrin- Schramm (HS), black tea (BT) and modified BT media. BCNF was purified (0.5 N NaOH) and quantified by dry weight, yield and productivity determination. Characterization and effect of gamma radiation (5–25 kGy) on BCNF were studied using Scanning Electron Microscope (SEM), Fourier transform infrared (FTIR) and X-Ray Diffraction (XRD). Bacterial and yeast isolates were identified as Acinetobacter lowffii and Candida krusei (synonymous: Pichia kudriavzevii), respectively. The highes...
Climate Change Impacts on Agriculture and Food Security in Egypt, 2020
The global climate change can influence agricultural productivity by altering the plant-microbe i... more The global climate change can influence agricultural productivity by altering the plant-microbe interactions. Plant-associated fungi play important roles in these interactions by regulating nutrient transformation in soils, nutrient availability for plants and plant health and growth. The abiotic stressors that increase with the changing climate result in significant alterations in these processes. These alterations are either as a response to the changing biology of the plant or due to the direct effect of the stressors on the fungi. In this chapter we retrospect the current knowledge on the plant-associated fungi and discuss the effects of the changing climate on their interactions with their hosts. The goal of this review is to emphasize the need for more research on plant-fungal interactions that can increase the resilience of crops to climate change.
The slow electron transfer between microbial outer membrane and electrode surface is considered o... more The slow electron transfer between microbial outer membrane and electrode surface is considered one of the limitations of Microbial Fuel Cell (MFC) performance. The aim of the present work is to assess the role of palladium α-lipoic acid nanocomplex compound (PLAC) in promoting bacteriaanode interfacial electron transfer, by studying the dielectric properties of Shewanella oneidensis WW-1 cell membrane and its contribution to biofilm formation on the anode. The results showed that adding PLAC increased bacterial cell membrane permeability and outer cell surface charge. Exopolysaccharides (EPS) and surface-bound proteins increased 2.27 and 1.14 fold, respectively upon adding 0.25% v/v PLAC. Dynamic Light Scattering (DLS) showed uniform distribution of Shewanella-PLAC biocomposite size while Zeta potential and Fourier Transform Infrared (FTIR) Spectroscopy results suggest that PLAC diffused inside the cells. Transmission Electron Microscope (TEM) images reveal Exopolysaccharide (EPS) mat around the cells when PLAC was added to the cells, also confirmed by the FTIR spectrum. Scanning Electron Microscope and Atomic Force Microscope (AFM) confirmed the thickness of biofilm in the presence of PLAC. The average voltage reached 492 mV (external resistance 1 KΩ) over 35 days using 0.25% v/v PLAC as compared to a few hours in MFCs lacking PLAC. The results suggest that the addition of PLAC assisted in interfacial direct electron transfer through enhancing biofilm formation, moreover, its hydrophilic/lipophilic nature facilitated the electron shuttling process from within the bacterial cell to the electrode surface suggesting the involvement of mediated electron transfer as well.
A biosurfactant producing Gram positive bacterium isolated from anodic biofilm of textile wastewa... more A biosurfactant producing Gram positive bacterium isolated from anodic biofilm of textile wastewater fed MFC was identified as Bacillus sp. MFC (Accession number: MT322244). Scanning Electron Microscopy of the bacterium showed appendages, the bacterium forms biofilm on Congo red agar medium. The obtained results showed that the addition of 5 mg/l endogenous biosurfactant to the bacterial cells resulted in 19-fold increase in bacterial surface-bound exopolysaccharides (EPS) and 1.94-fold increase in biofilm. However, when the bio-surfactant concentration increased to 20 and 40 mg/l, EPS and biofilm decreased and the cells lost their colony forming ability. The dielectric properties of the bacterial cells showed increase in conductivity and relative permittivity with increasing biosurfactant concentrations. The shape of the voltammogram currents peak, their location and Electrochemical impedance spectroscopy (EIS) suggest the involvement of biofilm as direct electron transfer pathway. The average voltage obtained was 0.65 V as compared to 0.45 V for the control MFC. Decolourization was tested for Congo red in a double chamber Microbial Fuel Cell (MFC), the results showed 2-fold increase in decolourization when biosurfactant is added post biofilm formation. The results confirm that Bacillus sp. MFC possess electrogenic properties and that adding low concentrations of endogenous biosurfactant to 24 h biofilm accelerates electron transfer by inducing perforations in the cell wall and increasing EPS as an electron transfer transient medium. Therefore, MFC performance can be enhanced.
Journal of Nuclear Technology in Applied Sciences, 2020
Black scurf disease caused by Rhizoctonia solani is a main yield limiting factor for potato tuber... more Black scurf disease caused by Rhizoctonia solani is a main yield limiting factor for potato tuber production as it leads to plant death. Using chemical treatment is not economic, therefore, the present study aimed to isolate naturally occurring antagonistic bacteria that could control R. solani. Bacillus sp. was selected among of 84 isolates secured from rhizosphere of healthy potato plant based on its ability to suppress the growth of the pathogen R. solani. Phylogenetic analysis of this strain based on 16S rRNA gene sequences showed highest similarity (99%) with Bacillus sp.; it was deposited in the GenBank under the accession number of MK030136. The strain culture filtrate containing protease, diffusible antibiotic, hydrogen cyanide and siderophore was capable of inhibiting growth of the pathogen up to 15 days compared to 7 and 10 days for other Bacillus isolates. It also produces indole acetic acid which promoted plant growth. Morphological and structural changes that took place as a result of Bacillus sp. and R. solani interaction were evaluated using light, scanning and transmission electron microscopies. The results showed that Bacillus sp. caused loss of structural integrity, abnormal coiling, shriveling and lysis of the R. solani hyphae, in addition to complete cytoplasm and internal organelles depletion. The Bacillus sp. under study was immobilized on nanoclay to form a bionanocomposite, which was stable and exhibited the biocontrol efficiency along 8 months storage. Both in vitro and greenhouse experiments showed high inhibition Physico-Chemical and Organolyptical Characteristics Of Cake Fortified By Irradiated Broccoli (Brassica Oleracea L.Var Italica) Powder (15) ABSTRACT KEYWORDS
The global climate change can influence agricultural productivity by altering the plant-microbe i... more The global climate change can influence agricultural productivity by altering the plant-microbe interactions. Plant-associated fungi play important roles in these interactions by regulating nutrient transformation in soils, nutrient availability for plants and plant health and growth. The abiotic stressors that increase with the changing climate result in significant alterations in these processes. These alterations are either as a response to the changing biology of the plant or due to the direct effect of the stressors on the fungi. In this chapter we retrospect the current knowledge on the plant-associated fungi and discuss the effects of the changing climate on their interactions with their hosts. The goal of this review is to emphasize the need for more research on plant-fungal interactions that can increase the resilience of crops to climate change.
Bacterial cellulose has drawn the attention for its unique properties and applications including;... more Bacterial cellulose has drawn the attention for its unique properties and applications including; medicine, pharmacy, food, agricultural, textile and electronics. The present study focused on the production of bacterial cellulose nanofibrils (BCNF) from black tea as cost effective alternative medium in addition to study the effect of gamma radiation on BCNF properties. A symbiotic culture of bacteria and yeast (SCOBY) were isolated from commercial Kombucha beverage and used for production of BCNF on Hestrin- Schramm (HS), black tea (BT) and modified BT media. BCNF was purified (0.5 N NaOH) and quantified by dry weight, yield and productivity determination. Characterization and effect of gamma radiation (5–25 kGy) on BCNF were studied using Scanning Electron Microscope (SEM), Fourier transform infrared (FTIR) and X-Ray Diffraction (XRD). Bacterial and yeast isolates were identified as Acinetobacter lowffii and Candida krusei (synonymous: Pichia kudriavzevii), respectively. The highes...
Climate Change Impacts on Agriculture and Food Security in Egypt, 2020
The global climate change can influence agricultural productivity by altering the plant-microbe i... more The global climate change can influence agricultural productivity by altering the plant-microbe interactions. Plant-associated fungi play important roles in these interactions by regulating nutrient transformation in soils, nutrient availability for plants and plant health and growth. The abiotic stressors that increase with the changing climate result in significant alterations in these processes. These alterations are either as a response to the changing biology of the plant or due to the direct effect of the stressors on the fungi. In this chapter we retrospect the current knowledge on the plant-associated fungi and discuss the effects of the changing climate on their interactions with their hosts. The goal of this review is to emphasize the need for more research on plant-fungal interactions that can increase the resilience of crops to climate change.
The slow electron transfer between microbial outer membrane and electrode surface is considered o... more The slow electron transfer between microbial outer membrane and electrode surface is considered one of the limitations of Microbial Fuel Cell (MFC) performance. The aim of the present work is to assess the role of palladium α-lipoic acid nanocomplex compound (PLAC) in promoting bacteriaanode interfacial electron transfer, by studying the dielectric properties of Shewanella oneidensis WW-1 cell membrane and its contribution to biofilm formation on the anode. The results showed that adding PLAC increased bacterial cell membrane permeability and outer cell surface charge. Exopolysaccharides (EPS) and surface-bound proteins increased 2.27 and 1.14 fold, respectively upon adding 0.25% v/v PLAC. Dynamic Light Scattering (DLS) showed uniform distribution of Shewanella-PLAC biocomposite size while Zeta potential and Fourier Transform Infrared (FTIR) Spectroscopy results suggest that PLAC diffused inside the cells. Transmission Electron Microscope (TEM) images reveal Exopolysaccharide (EPS) mat around the cells when PLAC was added to the cells, also confirmed by the FTIR spectrum. Scanning Electron Microscope and Atomic Force Microscope (AFM) confirmed the thickness of biofilm in the presence of PLAC. The average voltage reached 492 mV (external resistance 1 KΩ) over 35 days using 0.25% v/v PLAC as compared to a few hours in MFCs lacking PLAC. The results suggest that the addition of PLAC assisted in interfacial direct electron transfer through enhancing biofilm formation, moreover, its hydrophilic/lipophilic nature facilitated the electron shuttling process from within the bacterial cell to the electrode surface suggesting the involvement of mediated electron transfer as well.
A biosurfactant producing Gram positive bacterium isolated from anodic biofilm of textile wastewa... more A biosurfactant producing Gram positive bacterium isolated from anodic biofilm of textile wastewater fed MFC was identified as Bacillus sp. MFC (Accession number: MT322244). Scanning Electron Microscopy of the bacterium showed appendages, the bacterium forms biofilm on Congo red agar medium. The obtained results showed that the addition of 5 mg/l endogenous biosurfactant to the bacterial cells resulted in 19-fold increase in bacterial surface-bound exopolysaccharides (EPS) and 1.94-fold increase in biofilm. However, when the bio-surfactant concentration increased to 20 and 40 mg/l, EPS and biofilm decreased and the cells lost their colony forming ability. The dielectric properties of the bacterial cells showed increase in conductivity and relative permittivity with increasing biosurfactant concentrations. The shape of the voltammogram currents peak, their location and Electrochemical impedance spectroscopy (EIS) suggest the involvement of biofilm as direct electron transfer pathway. The average voltage obtained was 0.65 V as compared to 0.45 V for the control MFC. Decolourization was tested for Congo red in a double chamber Microbial Fuel Cell (MFC), the results showed 2-fold increase in decolourization when biosurfactant is added post biofilm formation. The results confirm that Bacillus sp. MFC possess electrogenic properties and that adding low concentrations of endogenous biosurfactant to 24 h biofilm accelerates electron transfer by inducing perforations in the cell wall and increasing EPS as an electron transfer transient medium. Therefore, MFC performance can be enhanced.
Journal of Nuclear Technology in Applied Sciences, 2020
Black scurf disease caused by Rhizoctonia solani is a main yield limiting factor for potato tuber... more Black scurf disease caused by Rhizoctonia solani is a main yield limiting factor for potato tuber production as it leads to plant death. Using chemical treatment is not economic, therefore, the present study aimed to isolate naturally occurring antagonistic bacteria that could control R. solani. Bacillus sp. was selected among of 84 isolates secured from rhizosphere of healthy potato plant based on its ability to suppress the growth of the pathogen R. solani. Phylogenetic analysis of this strain based on 16S rRNA gene sequences showed highest similarity (99%) with Bacillus sp.; it was deposited in the GenBank under the accession number of MK030136. The strain culture filtrate containing protease, diffusible antibiotic, hydrogen cyanide and siderophore was capable of inhibiting growth of the pathogen up to 15 days compared to 7 and 10 days for other Bacillus isolates. It also produces indole acetic acid which promoted plant growth. Morphological and structural changes that took place as a result of Bacillus sp. and R. solani interaction were evaluated using light, scanning and transmission electron microscopies. The results showed that Bacillus sp. caused loss of structural integrity, abnormal coiling, shriveling and lysis of the R. solani hyphae, in addition to complete cytoplasm and internal organelles depletion. The Bacillus sp. under study was immobilized on nanoclay to form a bionanocomposite, which was stable and exhibited the biocontrol efficiency along 8 months storage. Both in vitro and greenhouse experiments showed high inhibition Physico-Chemical and Organolyptical Characteristics Of Cake Fortified By Irradiated Broccoli (Brassica Oleracea L.Var Italica) Powder (15) ABSTRACT KEYWORDS
The global climate change can influence agricultural productivity by altering the plant-microbe i... more The global climate change can influence agricultural productivity by altering the plant-microbe interactions. Plant-associated fungi play important roles in these interactions by regulating nutrient transformation in soils, nutrient availability for plants and plant health and growth. The abiotic stressors that increase with the changing climate result in significant alterations in these processes. These alterations are either as a response to the changing biology of the plant or due to the direct effect of the stressors on the fungi. In this chapter we retrospect the current knowledge on the plant-associated fungi and discuss the effects of the changing climate on their interactions with their hosts. The goal of this review is to emphasize the need for more research on plant-fungal interactions that can increase the resilience of crops to climate change.
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Papers by Heba Maghrawy