الفهرس 
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Abstract
Bacterial cellulose (BC) has the best properties other than that produced from plants, it is very important biopolymers which can be used in many applications, in medical, pharmaceutical, textiles, paper, industries, water treatment and many other applications. In this study, Four bacterial isolats were obtained from guava as a rotten fruits on HS medium and tested for cellulose production. Two isolates were selected as high cellulose producing bacteria and completely identified by 16S ribosomal DNA sequencing, showing similarity about 99.8-100% to Komagataeibacter intermedius. Komagataeibacter intermedius on Seed medium gave high BC production being 17.82±0.76 g/L more than that produced on DSM, HS, GAM, SAM, GEM or COM medium. Komagataeibacter intermedius MO produced higher productivity of BC on Seed medium containing glucose and glycerol as carbon sources being 18.25± 0.30 g/L. Glucose concentration at 15 g/l gave the best production being 17.97±0.09 g/L. The organic nitrogen sources gave the bacterial growth and cellulose production by the test strain higher than that produced from inorganic nitrogen sources, which produced 20.00±2.00 g/L by using Seed medium containing yeast extract as an organic nitrogen source. The optimimum conditions of BC production including pH 7 and temperature 30ºC. Experiments showed that using of agitated culture at 150 rpm led to decreasing cellulose productivity by this strain to be 5.6±0.22 g/L.
In economic point of view, using cheap medium for production of bacterial cellulose is very good such as protein- based medium (Whey). In case of using the substitution with 50% of glucose as carbon source or yeast as nitrogen source were investigated to increase the yield of BC.
It was cleared that the highest productivity of BC were 22.73±0.64 and 21.11±0.58g/L that corresponding to 50% whey + 50% glucose and Seed medium, respectively. The structure of BC produced from the Komagataeibacter intermedius MO strain was studied by means of Fourier transform- infrared spectrum (FT-IR) and X-ray diffraction, Thermogravimetric analysis (TGA), Scanning electron microscopy (SEM) as well as mechanical properities . XRD analysis represented that the case of 50% Whey -50%Y medium was the best case which gave highest crystallinity index (75.7%) corresponding to other cases.
FTIR Spectra showed that absence of glucose and yeast from the medium led to production of BC with a lower hydrogen bond and degree of crystallization, the case of 50% Whey -50%Y medium also showed the higher crystallinity index (2.29) and this result was proved the data of Cr.I. obtained from XRD analysis, while FTIR showed that this case gave low MHBS (1.55), the protein -based medium (Whey) gave the highest MHBS(2.33) more than Seed medium (2.18).
Thermogravimetric analysis (TGA) results cleared that absence of glucose and yeast from the medium led to formation of BC with high ash content. It was noticed that the Ea of the BC based on protein-based medium substituted with 50% of yeast was correlated to its crystallinity which observed its maximum values with lowest ash content.
The tensile strength, deflection and young’s modulus (mechanical properties) were estimated for all BC samples, and studies showed that the greatest improvement in strength property of the BC using 50% Whey -50%Y medium that showed 30.0 MPa tensile strength and highest Cr. I. (75.7%) with highest elasticity.
Examination the morphology of BC pellicle by scanning electron microscopy (SEM) showed that BC samples had different morphology versus medium. Modified seed medium by replacing 50% of Y by whey exhibited cellulose structure between the cellulose fiber obtained by seed and whey medium. Moreover, bundles of fiber aggregated together and aligned in one direction that showed more ordered fibers. The surface morphology is in agreement with XRD results.
According to SEM, the Width of BC Fibers shifted to the nanoscale through the complete or partial replacement of the seed by whey medium.
Due to the best characterization of BC based on protein-based medium substituted with 50% of yeast, it was recommended for the medical application specially in tympanic membrane perforation which may the most common ear problem, the results represented that bacterial cellulose graft myringoplasty would be a good, simple, rapid and safe surgery that could be done under local anesthesia in outpatient clinic with short time of surgery.
Keywords: Bacterial cellulose, Komagataeibacter intermedius 2503MO, Production, Whey, Scan Electron Microscope (SEM), Fourier Transform Infrared (FT-IR), X-ray Diffraction (XRD), Medical Application.