Doaa Abdel Rahman Mahmoud Hassanin
@nrc.sci.eg
Pharmaceutical and Drug Industries Institute , Chemistry of Natural & Microbial Products Department
National Research Centre
EDUCATION
B.Sc. (1993)
Department of Botany, Faculty of Science, Cairo University, Egypt
M.Sc. (October, 1999)
Department of Microbiology, Faculty of Science, Cairo University, Egypt
The title of the thesis was" Studies on microbial proteases especially those digesting fibrin blood clots"
Ph. D (August, 2003)
Department of Microbiology, Faculty of Science, Ain Shams University, Egypt
The title of the thesis was" Studies on bacterial levansucrase”
RESEARCH, TEACHING, or OTHER INTERESTS
Microbiology, Biotechnology, Environmental Science, Biochemistry
Scopus Publications
Scopus Publications
Doaa A. R. Mahmoud
Springer International Publishing
Doaa Mahmoud and mohammad Farag
Egypts Presidential Specialized Council for Education and Scientific Research
Integrating sustainability in life became an urgent necessity. Currently tea sectors play important role in adopting new technologies in order to reduce tea wastes .Collection of these wastes for production of ethanol will contribute to the improvement of life and the environment. Simple technique was proposed for saccharification of spent tea leaves either by cellulase or fermentation with baker's yeast. Scanning electron microscope analysis showed certain modification for the morphology of both green and black tea leaves. Brunauer Emmett Teller analysis confirmed the increment in surface area of both tea leaves. X- Ray Diffraction analysis proved the amorphous nature of their cellulose with little crystallinity. This nature eases their saccharification because cellulose is usually susceptible to degradation in its amorphous form. The percentage of produced ethanol was 74.4% from spent green tea leaves and 80.7% from spent black tea leaves after 24 h at mild temperature. The habit of drinking tea in Egypt shed the light on a promising approach relies on the production of ethanol from tea wastes especially spent tea leaves.
Doaa Mahmoud
Egypts Presidential Specialized Council for Education and Scientific Research
Eco-friendly technique for invertase immobilization has been created. It is very simple and does not need a preparation of highly pure enzyme or an expensive carrier. The technique relies on mixing pretreated sawdust with baker's yeast in a closed system and comparing it with that in an open system. The technique introduces a practical and new insight into the role of carbon dioxide in modification of sawdust's surface and invertase immobilization. It also provides vital insights on the role of immobilization technique on the stability and activity of the enzyme. The storage stability of the immobilized invertase retained 93% of its activity after storage of 2 years at 4 oC. Although Invertase has been largely immobilized on different cellulosic materials, but the novelty of this study is the enzymatic synthesis of oligosaccharide by cold-adapted invertase at 20 oC.
A. A. Ahmed, A. A. Ali, Doaa A. R. Mahmoud, and A. M. El-Fiqi
Wiley
60P₂O₅-20CaO-(20-x) Na₂O-xAg₂O and 60P₂O₅-30CaO-(10-x) Na₂O-xAg₂O glasses, x = 0, 0.5,1, and 2 mol % were prepared using normal glass melting technique. The antibacterial activity of pressed disks of powdered glass (undoped and silver-doped glass) was investigated against S.aureus, P.aeruginosa, and E.coli micro-organisms using agar disk-diffusion assays at 37 °C for 24 h. The antibacterial activity was deduced from the inhibition zone diameter (IZD), zone of no bacterial growth, measured under the stated experimental conditions. The antibacterial activity increases with the increase in IZD and vice versa. Dissolution of glass in water at 37 °C, pH changes of water during glass dissolution, and concentrations of silver ions released from silver-doped glasses into water during their dissolution were determined. An increase in the concentration of silver ions released from silver-doped glasses into water was observed with increasing time of glass dissolution and with increasing Ag₂O content. The tested silver-free and silver-doped glasses demonstrated different antibacterial activity against the tested micro-organisms. For silver-free glasses, an increase in IZD was observed with the increase in the glass dissolution rate and with the decrease in pH of water. Also, the IZD showed an increase with increasing Ag₂O content of silver-doped glasses.
A.A. Ahmed, A.A. Ali, Doaa A.R. Mahmoud, and A.M. El-Fiqi
Elsevier BV
Doaa A. R. Mahmoud and Magda A. El Bendary
Springer Science and Business Media LLC
M. A. Esawy, D. A. R. Mahmoud, and A. F. A. Fattah
FapUNIFESP (SciELO)
Bacillus subtilis NRC33a levansucrase was immobilised on different carriers using different immobilisation methods including physical adsorption, covalent binding, ionic binding and entrapment. The immobilised enzyme prepared by covalent binding on chitosan through 3% gluteraldehyde had the highest immobilization yield (81.51%). Therefore, it was used as a typical example for Bacillus subtilis NRC33a immobilised levansucrase and its properties were investigated. The time of the reaction and substrate concentration revealed that the activity of the immobilised enzyme was relatively lower than the free enzyme. The immobilised levansucrase showed a slight increase in activity compared with the free enzyme above 35°C. The activation energies were 6.62 and 9.27 kcal mol-1 for free and immobilised enzyme respectively. Although the thermal stability of the immobilised levansucrase was significantly improved in comparison to the free form, the deactivation energy of the immobilised enzyme was lower than that of the free enzyme. The half life of the immobilised and free levansucrase was also determined. The effect of different pH values reported that at acidic pH the activity of the immobilised levansucrase was higher than that of the free enzyme. The study of pH stability of free and immobilised levansucrase showed that the immobilisation process protected the enzyme from alkaline and severe acidic media. The effect of various metal ions showed that the free levansucrase was more sensitive to the inhibitory effect of the investigated substances. Immobilised levansucrase retained 51.13% after 14 repeated uses.
Ahmed F. Abdel-Fattah, Doaa A. R. Mahmoud, and Mona A. T. Esawy
Springer Science and Business Media LLC
Publications
Book Chapter:
1-Forest Life under Control of Microbial Life Chapter 8
By Doaa A. R. Mahmoud
Agricultural and Biological Sciences » "New Advances and Contributions to Forestry Research", book edited by Andrew Akwasi Oteng-Amoako, ISBN 978-953-51-0529-9, Published: April 27, 2012 under CC BY 3.0 license DOI: 10.5772/35193
2-Mechanism of Microbial Biodegradation: Secrets of Biodegradation Chapter 6-1 By Doaa A. R. Mahmoud
Handbook of Biodegradable Materials Life edited by Gomaa A. M. Ali, & Abdel Salam H. Makhlouf, First Online: 27 August 2022 Springer Nature DOI: 10.1007/978-3-030-83783-9_24-1
Scientific Publications:
1-Production of Levansucrase from Bacillus subtilis NRC 33a and Enzymic Synthesis of Levan and Fructo-Oligosaccharides
Ahmed F.Abdel-Fattah, Doaa A.R. Mahmoud, Mona A.T. Esawy
Current Microbiology (2005),
2-Isolation of poly glutami Acid Flocculant Producing Bacteria from Extreme Egyptian Environments
Doaa A.R. Mahmoud
Journal of Applied Science Research 2(9):608-612 (2006)
3-Novel Physical Property for Levan as a Harmless Flocculating Agent
Doaa A. R. Mahmoud
Egypt. J. Biotechnology. Vol. 23(2006):320-328
4-Screening of New Bacterial Strains Producing Polyglutamic Acid Biopolymer Flocculant
Doaa A. R. Mahmoud
Egypt. J. Biotechnology. Vol. 23(2006):127-134
5-Immobilization of Invertase by a New Economical Method Using Wood Sawdust
Doaa A.R. Mahmoud
Australian Journal of Basic and Applied Sciences Vol.4
GRANT DETAILS
Projects as Principal Investigator:
1- Principal Investigator of National Project Supported by Science and Technology Developing Fund entitled "Improvement of Sugar Industry Process by using New Cold Active Dextranase"(2010 until 2014)
Projects as a member:
1-Member in a project of National technology alliances financially supported by ASRT (Academy of Scientific Research and Technology) Entitled: "Integrated pharmaceutical technology research and development"(From January 2020 to 2023)
2-Member in a project of Science and Technology Development Fund(STDF).Cairo-Egypt entitled" Synthesis and characterization of 3D bioactive glass (phosphate, borate or silicate glass)/Polymer (poly lactic acid) scaffold for bone engineering to serve as a controlled local delivery system for antibiotics (8030121). (2009-2011).
3-Member in a project of the Natio Research entitled "Synthesis of 3D scaffold for bone regeneration and cartilage reconstruction that can serve as a controlled local delivery system for anticancer drugs or antibiotics to treat bone cancer and osteomyelitis"(2008)
4-Member in a project of National Research entitled "Local production of lipase enzyme and its application in textile industry by innovative techniques"(2008).
5-Participated in a project of National Research Center was financially supported by Sugar Company and Integrated Industries. Cairo-Egypt entitled "Studies and Production of Dextran Ferment ally".
RESEARCH OUTPUTS (PATENTS, SOFTWARE, PUBLICATIONS, PRODUCTS)
Patents:
1-Patent entitled:" Production, immobilization, and purification of Invertase on wood sawdust" Awarded with a number (24840) at the Ministry of Scientific Research (Academy of Scientific Research & Technology) patent office. Cairo- Egypt. (19-4-2010)
2-Patent entitled: "Method for Immobilization of Invertase on Cellulosic Wastes by the Effect of CO2" Awarded with a number (28122) at the Ministry of Scientific Research (Academy of Scientific Research & Technology) patent office. Cairo- Egypt. (2-4-2017)
3-Patent entitled: "Production of Fructose by Using Palm Fiber" Registered with number (1285) 31-7-2011 at the Ministry of Scientific Research (Academy of Scientific Research & Technology) patent office. Cairo- Egypt.
1-2022: Dr. Yahya Abdullatif Award in cellulose, paper, and wood, from the National Research Center. Cairo-Egypt (Financial award of 5000 LE)
2-2018: Excellence Award from the National Research Center for a patent. Cairo-Egypt (Financial award of 25000 LE)
3-2017: Excellence Award from the Academy of Scientific Research for participating in the Fourth Cairo International Innovation Exhibition (Culture and Knowledge Hub). Cairo-Egypt (Financial award of 5000 LE)
4-2017: Silver Medal of the 9th International Invention Fair in Middle East (IFME) organized by Kuwait Science Club Kuwait
5-2015: Golden Medal of the1st World Invention Innovation Contest (WiC) organized by Korean Invention News (KINEWS)
6-2015: Golden Medal of the Exhibition of Egypt Invent
CONSULTANCY
Added as a reviewer in the reviewer list of the following Journals:
1- Letters in Applied Microbiology
2- Journal of Applied Microbiology
3- International Research Journal of Agricultural Science
4-African Journal of Microbiology Research
5- African Journal of Biotechnology
6-Electronic Journal of Biotechnology
Industry, Institute, or Organisation Collaboration
International Projects:
1- Member of a German project with financial support from KWS Saat AG Einbeck (Germany) in which bacteria and fungi associated with sugar beet were analyzed by independent cultivation-based techniques. The project was implemented at the University of Rostock - Germany (2003-2004).
2- A member of an Italian-Egyptian partnership project financially supported by ICGEP (International Center for Genetic Engineering and Biotechnology titled: “Surface Stabilization of Saponin Hydrolase on Agricultural Residues: New Biostimulants for Soybean Hydrolysis” (January 2015 until March 2016)
INDUSTRY EXPERIENCE
Improvement of the sugar industry by cold active dextranase
Production of industrial invertase and inverted syrup
STARTUP
Honey Corner Startup Company
SOCIAL, ECONOMIC, or ACADEMIC BENEFITS
Community Assessments:
1- 2022: Grand Award Judge Certificate from Society for Science Washington for participation in Regeneron International Science and Engineering Fair (Regeneron ISEF 2022)
2-2016: Shield from General Assembly National Institute, Canal language school for effort and outstanding support to raise the status of the educational process. Egypt
3- 2014: Appreciation certificate from World Union of Poets for media coverage "Towards Humanization of the World" at the headquarters of the Arab League in Cairo
4- 2013: Appreciation certificate for outstanding role in the press shows of Maadi Canal Schools. Egypt
5-2012: Appreciation certificate for contributing significantly to the betterment of society and giving support to Maadi Canal Schools. Egypt
Biographical record in Who is Who in the World 2013(inclusion which is limited to those individuals who have demonstrated outstanding achievement in their own fields of endeavor and who have, thereby, contributed significantly to the betterment of contemporary society). USA