Prof. Dr. Osama Darwesh | National Research Centre (original) (raw)

Papers by Prof. Dr. Osama Darwesh

Industrial Crops and Products, Feb 29, 2024

Waste Disposal & Sustainable Energy

Polyester/cotton (PET/C) blended fabric wastes are produced daily in huge amounts, which constitu... more Polyester/cotton (PET/C) blended fabric wastes are produced daily in huge amounts, which constitutes an economic loss and an environmental threat if it is not reused appropriately. Modern textile waste recycling technologies put much effort into developing fabric materials with unique properties, such as bioactivity or new optical goods based on modern technologies, especially nano-biotechnology. In this study, zinc oxide nanoparticles (ZnO-NPs) were biosynthesized using the aqueous extract of Dunaliella sp. and immobilized on PET/C waste fabrics after enzymatically activated with cellulases. The produced Dunaliella-ZnO-NPs (10–20 nm with a spherical shape) were characterized by High-resolution transmission electron microscopy (HRTEM), Fourier-transform infrared spectroscopy (FTIR), X-Ray diffraction analysis (XRD), and Scanning electron microscopy-energy dispersive X-ray analyzer (SEM-EDAX), and some functional groups, such as CH, CO, NH, and CN (due to the presence of carboxyl, pr...

Scientific Reports

In Egypt, sunflower charcoal-rot caused by Macrophomina phaseolina and maize late-wilt caused by ... more In Egypt, sunflower charcoal-rot caused by Macrophomina phaseolina and maize late-wilt caused by Magnaporthiopsis maydis are the most prevalent, and can lead to huge yield losses of both crops under epidemic conditions. In this study, the potential use of vermitea and wood vinegar for management of both diseases was investigated. Data revealed that, among the 17 bacterial strains obtained from vermitea, three strains named VCB-2, VCB-7 and VCB-11 were chosen for having the greatest in vitro inhibitory effect against M. phaseolina and M. maydis, with fungal inhibition values of 54.2; 61.7, 65.2; 74.0 and 57.1; 87.0% against both pathogens, respectively. These strains were identified as Bacillus amyloliquefaciens, Serratia marcescens and Bacillus velezensis, respectively. Wood vinegar significantly reduced the colony diameter of M. phaseolina and M. maydis in in vitro trials conducted on potato dextrose agar medium amended with the desired concentrations of 0.5, 1.0, 1.5, 2.0, and 2.5...

Egyptian Journal of Chemistry, Aug 29, 2021

Environmental application of nanomaterials to treat air, soil and wastewater pollutants has sever... more Environmental application of nanomaterials to treat air, soil and wastewater pollutants has several advantages due to the unique properties of the nanoparticles. In the literature, there are many positive reports of effective treatment processes for different environmental pollutants based on nanotechnology. However, successful laboratory-scale experiments do not imply that there are no challenges and concerns for the environmental application of nanomaterials on a large scale. Here, in this review, we briefly discuss the sources and types of environmental pollutants, the problems associated with their existence, and the conventional and nanotechnological methods of addressing them. The challenges facing the environmental application of nanotechnology in the field of removing pollutants were also discussed, in addition to suggestions and recommendations to address these challenges.

Biocatalysis and agricultural biotechnology, Mar 1, 2019

Considering the hygienic quality of infant-food is of great important, especially it is the prima... more Considering the hygienic quality of infant-food is of great important, especially it is the primary source of kids nutrition. Bacillus cereus has been recognized as a serious food-borne pathogen, causing outbreaks due to the produced enterotoxins including cytotoxin K (CytK), non-hemolytic enterotoxin (Nhe) and hemolysin BL (Hbl). In this study, two bacterial isolates, carrying the virulence encoding genes cytK, nheC, and hblA, were obtained from infant-foods. Using 16S rDNA sequence analysis, they were identified as Bacillus cereus MH031700 and MH031701. Then, they were tested for the antagonistic effect of some lactic acid bacterial strains. Results showed that cell free supernatant from Lactobacillus rhamnosus B-445 exhibited the highest antagonistic activity. In addition, this strain have reduced the growth of the toxicogenic Bacillus spp in mixed cultures. In further experiments, proliferation of B. cereus strains was evaluated in presence/absence of microencapsulated or spraydried L. rhamnosus B-445 in formulated infant-food mixtures. Microencapsulated cells exhibited higher effeciency for growth inhibition than spray dried cells. Incorporating microencapsulated or spray dried L. rhamnosus B-445 not only inhibited the proliferation of B. cereus strains that existed in infant-foods but also it reduced their count from ∼ Log 3.0 to ∼ Log 2.0 after 2 and 3 h at room temperature (25°C), respectively. Similar results were achieved at low temperature (7.0 ± 2.0°C) but after 4 and 8 h, respectively. Our results showed the potential efficiency of L. rhamnosus B-445 in suppressing toxicogenic B. cereus strains by its supplementation into infantfoods.

The investigation was designed to determine the antiviral, antimicrobial and schistosomicidal, ef... more The investigation was designed to determine the antiviral, antimicrobial and schistosomicidal, effects of the leaf essential oil of Eucalyptus camaldulensis. Rotavirus Wa strain, Coxsackievirus B4, and herpes virus type 1 were affected by essential oil with percentage of reduction 50%, 53.3%, and 90% respectively. On the other hand, no effect was found at all on adenovirus type 7. Regarding antimicrobial effect, essential oil has high effects against gram positive and negative bacteria with inhibition zones ranged from 9.3 to 12.5 Mm. The same effect was observed on yeast (21% inhibition) and fungi (10% inhibition). The Scanning Electron Microscope observation showed that IC 90 of essential oil produced sever damage in schistosoma worm's typography. Therefore, the essential oils from E. camaldulensis are active candidates and could be used as RNA antivirus, antimicrobial and shistosomicidal agents in new drugs preparation for therapy of infectious diseases.

Applied sciences, Dec 11, 2020

The color of food is a critical factor influencing its general acceptance. Owing to the effects o... more The color of food is a critical factor influencing its general acceptance. Owing to the effects of chemical colorants on health, current research is directly aimed at producing natural and healthy food colorants from microbial sources. A pigment-producing fungal isolate, obtained from soil samples and selected based on its rapidity and efficiency in producing red pigments, was identified as Monascus ruber OMNRC45. The culture conditions were optimized to enhance pigment production under submerged fermentation. The optimal temperature and pH for the highest red pigment yield were 30 • C and 6.5, respectively. The optimum carbon and nitrogen sources were rice and peptone, respectively. The usefulness of the pigment produced as a food colorant was evaluated by testing for contamination by the harmful mycotoxin citrinin and assessing its biosafety in mice. In addition, sensory evaluation tests were performed to evaluate the overall acceptance of the pigment as a food colorant. The results showed that M. ruber OMNRC45 was able to rapidly and effectively produce dense natural red pigment under the conditions of submerged fermentation without citrinin production. The findings of the sensory and biosafety assessments indicated the biosafety and applicability of the red Monascus pigment as a food colorant.

Biocatalysis and agricultural biotechnology, Mar 1, 2019

Selenium nanoparticles (SeNPs) as environmental friendly agent were applied for induces enhanceme... more Selenium nanoparticles (SeNPs) as environmental friendly agent were applied for induces enhancement in the growth of three different groundnut (Arachis hypogaea L.) cultivars (NC, Gregory and Giza 6). The tested cultivars are different at biochemical and physiological levels. Foliar application of SeNPs (0, 20 and 40 ppm) was applied during vegetative stage. Foliar application of SeNPs (0, 20 and 40 ppm) was applied during vegetative stage. Effect of SeNPs on growth depends upon the used concentration of selenium nanoparticles and groundnut cultivar. Application of SeNPs improved growth of Gerogory cv. and Giza 6 cv., respectively, while the growth parameters of NC cv. were relatively negative affected by SeNPs treatments. The effects of SeNPs on growth of groundnut cultivars were linked with physiological and biochemical plant properties i.e. the changes in photosynthetic pigments, lipid peroxidation, antioxidants enzymes (catalase, peroxidase and ascorbic acid peroxidase), total phenols, total flavonoids and total soluble sugars. Generally, nano selenium act as stimulator and/or stressor enhanced the antioxidant defense systems in tested groundnut cultivars leads to the improvement of plant tolerance under sandy soil conditions.

Biotechnology Reports, Dec 1, 2019

Knowledge about the risks of the nanoparticles application on the plant development and human hea... more Knowledge about the risks of the nanoparticles application on the plant development and human health is still limited. Different concentrations of nano-selenium (0, 20 and 40 ppm) were applied to three different Egyptian groundnut (Arachis hypogaea l.) cultivars; (NC, Gregory and Giza 6) under sandy soil conditions at vegetative growth stage to investigate their effects on yield components, protein profile, fatty acids composition, total antioxidant content and cytotoxicity of yielded seeds. The results indicate that the tested Nano-Selenium (Nano-Se) concentrations improved yield components and seeds oil. However, Nano-Se altered protein signatures as well as fatty acids composition by increasing unsaturated fatty acids and/or decreasing saturated fatty acids as compared with control, the cytotoxicity assessments proved safety of the yield for human health.

Biocatalysis and agricultural biotechnology, 2019

Environmental applications of selective lignin-degrading fungi and enzymes are of great interest ... more Environmental applications of selective lignin-degrading fungi and enzymes are of great interest as alternate technologies for paper industry (biopulping), biofuels, organic fertilizers, animal feeds. For this reason, the current study aimed to isolate selective delignifying fungi to convert the abundant lignocellulosic agricultural wastes into value-added products. From five lignocellulolytic fungi isolated from agricultural soil rich with partial decayed wooden trimmings, one isolate was selected due to its selectivity towards lignin degradation. The selected non-cellulolytic fungus isolate was identified according to morphological and molecular techniques as Aspergillus flavus EGYPTA5 with accession number MH425453. This fungal strain has been proven to cause an efficient and selective degradation of lignin in agricultural lignocellulosic wastes without affecting cellulose content. Lignin peroxidases, laccase, polyphenol oxidase, nitrate reductase and cellulase enzymes from investigating strain were assayed in the current research. All the tested enzymes except cellulase were produced with various activity degrees. Lignin peroxidases were the most active enzyme produced under experimental conditions (reached to 2.45 U/ml). Physical and chemical analysis of lignocellulosic agricultural wastes as well as FTIR analysis confirmed that A. flavus EGYPTA5 could be used as an alternative technology for biotreatment of lignin-rich cellulosic wastes to degrade lignin without affecting cellulose fibers. The isolated fungus and/or its specific-lignolytic enzymes could be applied in various environmental and industrial applications.

International journal of pharma and bio sciences, Oct 17, 2016

Harvesting of microalgae Scenedesmus sp. (strain A1) using the natural polymer chitosan was inves... more Harvesting of microalgae Scenedesmus sp. (strain A1) using the natural polymer chitosan was investigated. Different chitosan concentrations, i.e., 10, 20, 40, 60 and 80 ppm were used in the pH range 6 to 10 and cultural cell densities values equivalent to 1, 2 and 3 abs680. Without the addition of chitosan, the increase in pH of the culture led to limited cell sedimentation. The addition of chitosan to the cultures at concentrations ranged from 10 to 80 ppm caused bio-flocculation followed by noticeable sedimentation of the trailed microalgae. The harvesting efficiency of Scenedesmus sp. using chitosan is very sensitive to the pH of the algal culture and pH 7 and 8 were the most suitable ones. In culture with OD680=1, 80 ppm chitosan is able to achieve 74% flocculation efficiency at pH 8, while 40 ppm chitosan caused 60.1% flocculation when pH value adjusted at 7. It could be concluded that, the cultural cell density determines the optimal chitosan dosage required for flocculation, the highest sedimentation percentage using 40 ppm chitosan could be achieved under pH 7 and OD3 (82.1%). In addition, in acidic and neutral cultures, the flocculation efficiency (FE) tends to be higher in case of dense cultures.

International Journal of Biological Macromolecules, Mar 1, 2021

Wastewater contaminated with dyes is discharged by huge amount daily, and involved many hazardous... more Wastewater contaminated with dyes is discharged by huge amount daily, and involved many hazardous materials. Thus, this study focused on introducing low cost, ecofriendly and available removal agent (lignin-based adsorbent). Three adsorbents, APKL-4, APKL-5 and APKL-6 were obtained using gradient acid precipitation technology and used for methylene blue (MB) removal. The samples were characterized by SEM, FT-IR and zeta potential analyzer. The results indicated that the three adsorbents exhibit significantly different adsorption behavior due to the structural differences caused by fractionation. The APKL-5 and APKL-6 have fewer hydrophilic groups in their molecules and thus have more adsorption active sites to load MB molecules. A pore structure inside of APKL-5 molecules is form in acid fractionation, which allows it to carry more MB molecules. The adsorption capacity of APKL-5 increased 3.8 times (from 345 to 1310 mg g-1) in the alkaline solution which showing excellent pH responsiveness. This paper presents a new promising approach for preparing high efficiency, low cost and eco-friendly adsorbents and builds a foundation for developing further applications of lignin-based adsorbents.

Current Bioactive Compounds, Jun 12, 2018

Heliyon, Mar 1, 2019

Lignocellulosic fibers, which obtained from Citrus trees trimmings, were modified with Aspergillu... more Lignocellulosic fibers, which obtained from Citrus trees trimmings, were modified with Aspergillus flavus (EGYPTA5) enzymes. The non-modified and the modified lignocellulosic fibers were used with low density polyethylene (LDPE) by melt blending brabender method at 170 C with different ratio (5, 10 and 20 wt%) to obtain wood plastic composites (WPC). The prepared samples were characterized using Fourier-transformed infrared (FT-IR), Scan Electron Microscope (SEM), and Water vapor transmission rate (WVTR) as well as, the mechanical, thermal, biodegradability and swelling properties were examined. The fabricated WPC displayed good mechanical and thermal properties compare with pure LDPE. Also, the WVTR was enhanced by the addition of modified lignocellulosic fibers

Colloids and Surfaces B: Biointerfaces, May 1, 2018

Highlights  Cu-BTC MOF was directly in-grown within synthetic fabrics by using simple technique ... more Highlights  Cu-BTC MOF was directly in-grown within synthetic fabrics by using simple technique  Contents of MOF and Cu were 97.14-127.33 mg/g and 30.5940.10 mg/g, respectively  Cu-BTC/fabric was exhibited good biological activities against different microbes  The MIC for the residual MOF powder was 60-70 mg/mL, for the different microbes  At using 10 mg/mL, no eco-toxicity was detected for Cu-BTC/fabric hybrid

Aquaculture Research, Apr 24, 2022

Environmental Science and Pollution Research, Oct 3, 2022

Currently, bionanotechnologies are attracting great interest due to their promising results and p... more Currently, bionanotechnologies are attracting great interest due to their promising results and potential benefits on many aspects of life. In this study, the objectives was to biosynthesis CuO-NPs using cell-free extract(s) of copper-resistant fungi and use them in bioremediation of textile industry wastewater. Out of 18 copper-resistant fungal isolates, the novel fungus strain Fusarium oxysporum OSF18 was selected for this purpose. This strain showed a high efficiency in extracellular reducing copper ions to their nano-form. The myco-synthesized CuO-NPs were characterized using UV-Vis spectroscopy, HRTEM, FTIR, and XRD and were found to be spherical nanocrystals with the size range of 21-47 nm. The bio-synthesized CuO-NPs showed promising antimicrobial activity as well as high efficiency in removing heavy metals and textile dye from industrial wastewater. The myco-synthesized CuO-NPs immobilized in alginate beads exhibited superior microbial disinfection (99.995%), heavy metals removal (93, 55, and 30 % for Pb, Cr, and Ni, respectively), and dye decolorization (90%). Such results represent a promising step to produce an eco-friendly, cost-effective, and easy-to handle tool for the bioremediation of textile industry wastewater.

Industrial Crops and Products, Feb 29, 2024

Waste Disposal & Sustainable Energy

Polyester/cotton (PET/C) blended fabric wastes are produced daily in huge amounts, which constitu... more Polyester/cotton (PET/C) blended fabric wastes are produced daily in huge amounts, which constitutes an economic loss and an environmental threat if it is not reused appropriately. Modern textile waste recycling technologies put much effort into developing fabric materials with unique properties, such as bioactivity or new optical goods based on modern technologies, especially nano-biotechnology. In this study, zinc oxide nanoparticles (ZnO-NPs) were biosynthesized using the aqueous extract of Dunaliella sp. and immobilized on PET/C waste fabrics after enzymatically activated with cellulases. The produced Dunaliella-ZnO-NPs (10–20 nm with a spherical shape) were characterized by High-resolution transmission electron microscopy (HRTEM), Fourier-transform infrared spectroscopy (FTIR), X-Ray diffraction analysis (XRD), and Scanning electron microscopy-energy dispersive X-ray analyzer (SEM-EDAX), and some functional groups, such as CH, CO, NH, and CN (due to the presence of carboxyl, pr...

Scientific Reports

In Egypt, sunflower charcoal-rot caused by Macrophomina phaseolina and maize late-wilt caused by ... more In Egypt, sunflower charcoal-rot caused by Macrophomina phaseolina and maize late-wilt caused by Magnaporthiopsis maydis are the most prevalent, and can lead to huge yield losses of both crops under epidemic conditions. In this study, the potential use of vermitea and wood vinegar for management of both diseases was investigated. Data revealed that, among the 17 bacterial strains obtained from vermitea, three strains named VCB-2, VCB-7 and VCB-11 were chosen for having the greatest in vitro inhibitory effect against M. phaseolina and M. maydis, with fungal inhibition values of 54.2; 61.7, 65.2; 74.0 and 57.1; 87.0% against both pathogens, respectively. These strains were identified as Bacillus amyloliquefaciens, Serratia marcescens and Bacillus velezensis, respectively. Wood vinegar significantly reduced the colony diameter of M. phaseolina and M. maydis in in vitro trials conducted on potato dextrose agar medium amended with the desired concentrations of 0.5, 1.0, 1.5, 2.0, and 2.5...

Egyptian Journal of Chemistry, Aug 29, 2021

Environmental application of nanomaterials to treat air, soil and wastewater pollutants has sever... more Environmental application of nanomaterials to treat air, soil and wastewater pollutants has several advantages due to the unique properties of the nanoparticles. In the literature, there are many positive reports of effective treatment processes for different environmental pollutants based on nanotechnology. However, successful laboratory-scale experiments do not imply that there are no challenges and concerns for the environmental application of nanomaterials on a large scale. Here, in this review, we briefly discuss the sources and types of environmental pollutants, the problems associated with their existence, and the conventional and nanotechnological methods of addressing them. The challenges facing the environmental application of nanotechnology in the field of removing pollutants were also discussed, in addition to suggestions and recommendations to address these challenges.

Biocatalysis and agricultural biotechnology, Mar 1, 2019

Considering the hygienic quality of infant-food is of great important, especially it is the prima... more Considering the hygienic quality of infant-food is of great important, especially it is the primary source of kids nutrition. Bacillus cereus has been recognized as a serious food-borne pathogen, causing outbreaks due to the produced enterotoxins including cytotoxin K (CytK), non-hemolytic enterotoxin (Nhe) and hemolysin BL (Hbl). In this study, two bacterial isolates, carrying the virulence encoding genes cytK, nheC, and hblA, were obtained from infant-foods. Using 16S rDNA sequence analysis, they were identified as Bacillus cereus MH031700 and MH031701. Then, they were tested for the antagonistic effect of some lactic acid bacterial strains. Results showed that cell free supernatant from Lactobacillus rhamnosus B-445 exhibited the highest antagonistic activity. In addition, this strain have reduced the growth of the toxicogenic Bacillus spp in mixed cultures. In further experiments, proliferation of B. cereus strains was evaluated in presence/absence of microencapsulated or spraydried L. rhamnosus B-445 in formulated infant-food mixtures. Microencapsulated cells exhibited higher effeciency for growth inhibition than spray dried cells. Incorporating microencapsulated or spray dried L. rhamnosus B-445 not only inhibited the proliferation of B. cereus strains that existed in infant-foods but also it reduced their count from ∼ Log 3.0 to ∼ Log 2.0 after 2 and 3 h at room temperature (25°C), respectively. Similar results were achieved at low temperature (7.0 ± 2.0°C) but after 4 and 8 h, respectively. Our results showed the potential efficiency of L. rhamnosus B-445 in suppressing toxicogenic B. cereus strains by its supplementation into infantfoods.

The investigation was designed to determine the antiviral, antimicrobial and schistosomicidal, ef... more The investigation was designed to determine the antiviral, antimicrobial and schistosomicidal, effects of the leaf essential oil of Eucalyptus camaldulensis. Rotavirus Wa strain, Coxsackievirus B4, and herpes virus type 1 were affected by essential oil with percentage of reduction 50%, 53.3%, and 90% respectively. On the other hand, no effect was found at all on adenovirus type 7. Regarding antimicrobial effect, essential oil has high effects against gram positive and negative bacteria with inhibition zones ranged from 9.3 to 12.5 Mm. The same effect was observed on yeast (21% inhibition) and fungi (10% inhibition). The Scanning Electron Microscope observation showed that IC 90 of essential oil produced sever damage in schistosoma worm's typography. Therefore, the essential oils from E. camaldulensis are active candidates and could be used as RNA antivirus, antimicrobial and shistosomicidal agents in new drugs preparation for therapy of infectious diseases.

Applied sciences, Dec 11, 2020

The color of food is a critical factor influencing its general acceptance. Owing to the effects o... more The color of food is a critical factor influencing its general acceptance. Owing to the effects of chemical colorants on health, current research is directly aimed at producing natural and healthy food colorants from microbial sources. A pigment-producing fungal isolate, obtained from soil samples and selected based on its rapidity and efficiency in producing red pigments, was identified as Monascus ruber OMNRC45. The culture conditions were optimized to enhance pigment production under submerged fermentation. The optimal temperature and pH for the highest red pigment yield were 30 • C and 6.5, respectively. The optimum carbon and nitrogen sources were rice and peptone, respectively. The usefulness of the pigment produced as a food colorant was evaluated by testing for contamination by the harmful mycotoxin citrinin and assessing its biosafety in mice. In addition, sensory evaluation tests were performed to evaluate the overall acceptance of the pigment as a food colorant. The results showed that M. ruber OMNRC45 was able to rapidly and effectively produce dense natural red pigment under the conditions of submerged fermentation without citrinin production. The findings of the sensory and biosafety assessments indicated the biosafety and applicability of the red Monascus pigment as a food colorant.

Biocatalysis and agricultural biotechnology, Mar 1, 2019

Selenium nanoparticles (SeNPs) as environmental friendly agent were applied for induces enhanceme... more Selenium nanoparticles (SeNPs) as environmental friendly agent were applied for induces enhancement in the growth of three different groundnut (Arachis hypogaea L.) cultivars (NC, Gregory and Giza 6). The tested cultivars are different at biochemical and physiological levels. Foliar application of SeNPs (0, 20 and 40 ppm) was applied during vegetative stage. Foliar application of SeNPs (0, 20 and 40 ppm) was applied during vegetative stage. Effect of SeNPs on growth depends upon the used concentration of selenium nanoparticles and groundnut cultivar. Application of SeNPs improved growth of Gerogory cv. and Giza 6 cv., respectively, while the growth parameters of NC cv. were relatively negative affected by SeNPs treatments. The effects of SeNPs on growth of groundnut cultivars were linked with physiological and biochemical plant properties i.e. the changes in photosynthetic pigments, lipid peroxidation, antioxidants enzymes (catalase, peroxidase and ascorbic acid peroxidase), total phenols, total flavonoids and total soluble sugars. Generally, nano selenium act as stimulator and/or stressor enhanced the antioxidant defense systems in tested groundnut cultivars leads to the improvement of plant tolerance under sandy soil conditions.

Biotechnology Reports, Dec 1, 2019

Knowledge about the risks of the nanoparticles application on the plant development and human hea... more Knowledge about the risks of the nanoparticles application on the plant development and human health is still limited. Different concentrations of nano-selenium (0, 20 and 40 ppm) were applied to three different Egyptian groundnut (Arachis hypogaea l.) cultivars; (NC, Gregory and Giza 6) under sandy soil conditions at vegetative growth stage to investigate their effects on yield components, protein profile, fatty acids composition, total antioxidant content and cytotoxicity of yielded seeds. The results indicate that the tested Nano-Selenium (Nano-Se) concentrations improved yield components and seeds oil. However, Nano-Se altered protein signatures as well as fatty acids composition by increasing unsaturated fatty acids and/or decreasing saturated fatty acids as compared with control, the cytotoxicity assessments proved safety of the yield for human health.

Biocatalysis and agricultural biotechnology, 2019

Environmental applications of selective lignin-degrading fungi and enzymes are of great interest ... more Environmental applications of selective lignin-degrading fungi and enzymes are of great interest as alternate technologies for paper industry (biopulping), biofuels, organic fertilizers, animal feeds. For this reason, the current study aimed to isolate selective delignifying fungi to convert the abundant lignocellulosic agricultural wastes into value-added products. From five lignocellulolytic fungi isolated from agricultural soil rich with partial decayed wooden trimmings, one isolate was selected due to its selectivity towards lignin degradation. The selected non-cellulolytic fungus isolate was identified according to morphological and molecular techniques as Aspergillus flavus EGYPTA5 with accession number MH425453. This fungal strain has been proven to cause an efficient and selective degradation of lignin in agricultural lignocellulosic wastes without affecting cellulose content. Lignin peroxidases, laccase, polyphenol oxidase, nitrate reductase and cellulase enzymes from investigating strain were assayed in the current research. All the tested enzymes except cellulase were produced with various activity degrees. Lignin peroxidases were the most active enzyme produced under experimental conditions (reached to 2.45 U/ml). Physical and chemical analysis of lignocellulosic agricultural wastes as well as FTIR analysis confirmed that A. flavus EGYPTA5 could be used as an alternative technology for biotreatment of lignin-rich cellulosic wastes to degrade lignin without affecting cellulose fibers. The isolated fungus and/or its specific-lignolytic enzymes could be applied in various environmental and industrial applications.

International journal of pharma and bio sciences, Oct 17, 2016

Harvesting of microalgae Scenedesmus sp. (strain A1) using the natural polymer chitosan was inves... more Harvesting of microalgae Scenedesmus sp. (strain A1) using the natural polymer chitosan was investigated. Different chitosan concentrations, i.e., 10, 20, 40, 60 and 80 ppm were used in the pH range 6 to 10 and cultural cell densities values equivalent to 1, 2 and 3 abs680. Without the addition of chitosan, the increase in pH of the culture led to limited cell sedimentation. The addition of chitosan to the cultures at concentrations ranged from 10 to 80 ppm caused bio-flocculation followed by noticeable sedimentation of the trailed microalgae. The harvesting efficiency of Scenedesmus sp. using chitosan is very sensitive to the pH of the algal culture and pH 7 and 8 were the most suitable ones. In culture with OD680=1, 80 ppm chitosan is able to achieve 74% flocculation efficiency at pH 8, while 40 ppm chitosan caused 60.1% flocculation when pH value adjusted at 7. It could be concluded that, the cultural cell density determines the optimal chitosan dosage required for flocculation, the highest sedimentation percentage using 40 ppm chitosan could be achieved under pH 7 and OD3 (82.1%). In addition, in acidic and neutral cultures, the flocculation efficiency (FE) tends to be higher in case of dense cultures.

International Journal of Biological Macromolecules, Mar 1, 2021

Wastewater contaminated with dyes is discharged by huge amount daily, and involved many hazardous... more Wastewater contaminated with dyes is discharged by huge amount daily, and involved many hazardous materials. Thus, this study focused on introducing low cost, ecofriendly and available removal agent (lignin-based adsorbent). Three adsorbents, APKL-4, APKL-5 and APKL-6 were obtained using gradient acid precipitation technology and used for methylene blue (MB) removal. The samples were characterized by SEM, FT-IR and zeta potential analyzer. The results indicated that the three adsorbents exhibit significantly different adsorption behavior due to the structural differences caused by fractionation. The APKL-5 and APKL-6 have fewer hydrophilic groups in their molecules and thus have more adsorption active sites to load MB molecules. A pore structure inside of APKL-5 molecules is form in acid fractionation, which allows it to carry more MB molecules. The adsorption capacity of APKL-5 increased 3.8 times (from 345 to 1310 mg g-1) in the alkaline solution which showing excellent pH responsiveness. This paper presents a new promising approach for preparing high efficiency, low cost and eco-friendly adsorbents and builds a foundation for developing further applications of lignin-based adsorbents.

Current Bioactive Compounds, Jun 12, 2018

Heliyon, Mar 1, 2019

Lignocellulosic fibers, which obtained from Citrus trees trimmings, were modified with Aspergillu... more Lignocellulosic fibers, which obtained from Citrus trees trimmings, were modified with Aspergillus flavus (EGYPTA5) enzymes. The non-modified and the modified lignocellulosic fibers were used with low density polyethylene (LDPE) by melt blending brabender method at 170 C with different ratio (5, 10 and 20 wt%) to obtain wood plastic composites (WPC). The prepared samples were characterized using Fourier-transformed infrared (FT-IR), Scan Electron Microscope (SEM), and Water vapor transmission rate (WVTR) as well as, the mechanical, thermal, biodegradability and swelling properties were examined. The fabricated WPC displayed good mechanical and thermal properties compare with pure LDPE. Also, the WVTR was enhanced by the addition of modified lignocellulosic fibers

Colloids and Surfaces B: Biointerfaces, May 1, 2018

Highlights  Cu-BTC MOF was directly in-grown within synthetic fabrics by using simple technique ... more Highlights  Cu-BTC MOF was directly in-grown within synthetic fabrics by using simple technique  Contents of MOF and Cu were 97.14-127.33 mg/g and 30.5940.10 mg/g, respectively  Cu-BTC/fabric was exhibited good biological activities against different microbes  The MIC for the residual MOF powder was 60-70 mg/mL, for the different microbes  At using 10 mg/mL, no eco-toxicity was detected for Cu-BTC/fabric hybrid

Aquaculture Research, Apr 24, 2022

Environmental Science and Pollution Research, Oct 3, 2022

Currently, bionanotechnologies are attracting great interest due to their promising results and p... more Currently, bionanotechnologies are attracting great interest due to their promising results and potential benefits on many aspects of life. In this study, the objectives was to biosynthesis CuO-NPs using cell-free extract(s) of copper-resistant fungi and use them in bioremediation of textile industry wastewater. Out of 18 copper-resistant fungal isolates, the novel fungus strain Fusarium oxysporum OSF18 was selected for this purpose. This strain showed a high efficiency in extracellular reducing copper ions to their nano-form. The myco-synthesized CuO-NPs were characterized using UV-Vis spectroscopy, HRTEM, FTIR, and XRD and were found to be spherical nanocrystals with the size range of 21-47 nm. The bio-synthesized CuO-NPs showed promising antimicrobial activity as well as high efficiency in removing heavy metals and textile dye from industrial wastewater. The myco-synthesized CuO-NPs immobilized in alginate beads exhibited superior microbial disinfection (99.995%), heavy metals removal (93, 55, and 30 % for Pb, Cr, and Ni, respectively), and dye decolorization (90%). Such results represent a promising step to produce an eco-friendly, cost-effective, and easy-to handle tool for the bioremediation of textile industry wastewater.