DETERMINATION OF THE PHYSIOCHEMICAL PROPERTIES OF BACTERIAL CELLULOSE PRODUCED BY LOCAL ISOLATES OF ACETOBACTER XYLINUM.

The recent study aimed to isolates Acetobacter xylinum from local home vinegar samples processed of apple, dates and grape. From the total fifty; Twenty-one isolates observed on the surface of HS-agar medium, only four isolates showed transparent zone around the colony on GYC agar plates. The isolates (B1, B2, B3 and B4) were examined for bacterial cellulose production in HS broth medium. The dry weight of crude cellulose produced by each isolates was measured and ranged from 0.36 - 0.42 gm. The pH value of bacterial cellulose were (6.2 - 6.9), approximately equal and nearly to the neutral values with comparison with plant cellulose. The thickness of bacterial cellulose membrane is a key parameter in preparing film, the initial thickness of the wet BC membrane was measured as 32 micrometers and after drying the computed thickness of BC membrane decreased to 0.4 micrometers. The average tensile strength value and the average elongation at break value of the dried BC films were 34.5 MPa and 5.2% respectively. The micrograph of BC shows three dimensional porous network structure formed by ribbon fibrils, randomness of fiber distribution without any specific orientation. The SEM micrograph obtained for the purified Bacterial Cellulose (BC) shown a very similar structure with the commercial Plant Cellulose (PC). Furthermore, the fibrils were densely packed ; the aggregated BC showed flat and were smoother surface compared to the PC. X-ray diffraction analysis is used to study the physical properties of both BC and PC samples such as morphology, the degree of crystallinity, crystal size and to categorize cellulose as type Ior I. 2 range 5o to 40o is usually adequate to cover the most important area of the XRD pattern. The pattern for BC revealed four main peaks were at 2 = 14.53, 16.78, 22.79 and 34.67, corresponding to the crystallographic peak plane of (110), (110) (200) and (004), respectively. The X-ray diffractograms of purified BC sample showed their amorphous nature. The distinguishing broad peaks at 3452.58 cm-1 for BC and 3356.14 cm-1 for PC indicates OH is stretching intra molecular H-bond for cellulose1. Sharp peaks appeared CH stretching at 2924.09 cm-1 in BC and 2900.94 cm- 1 in The pattern for BC revealed four main peaks were at 2 = 14.53, 16.78, 22.79 and 34.67, corresponding to the crystallographic peak plane of (110), (110) (200) and (004), respectively. The X-ray diffracts grams of purified BC sample showed their amorphous nature. The FTIR spectrum shown the distinguishing broad peaks at 3452.58 cm-1 for BC and 3356.14 cm-1 for PC indicate OH is stretching intermolecular H-bond for cellulose 1. Sharp peaks appeared CH stretching at 2924.09 cm-1 in BC and 2900.94 cm-1 in PC. Overall, these data suggested that the BC and PC samples were the typical profile of the cellulose I crystalline structure and is typical of cellulose isolated from other fiber sources. The present results proved that BC and PC have a similar chemical bond and functional groups. [ABSTRACT FROM AUTHOR]