Statistical optimization and characterization of a biocellulose produced by local Egyptian isolate Komagataeibacter hansenii AS.5.

Abstract

Optimization of the culture parameters used for biocellulose (BC) production by a previously isolated bacterial strain (Komagataeibacter hansenii AS.5) was carried out. The effect of nine culture parameters on BC production was evaluated by implementing the Plackett-Burman design, and the results revealed that, the most significant variables affecting BC production were MgSO4, ethanol, pH and yeast extract. A three-level and four-factor Box-Behnken design was applied to determine the optimum level of each significant variable. According to the results of the Plackett-Burman and Box-Behnken designs, the following medium composition and parameters were calculated to be optimum (g/l): glucose 25, yeast extract 13, MgSO40.15, KH2PO4 2, ethanol 7.18\u202fml/l, pH\u202f5.5, inoclume size 7%, cultivation temperature 20\u202f°C and incubation time 9\u202fdays. Characterization of purified BC was performed to determine the network morphology by scanning electron microscopy, crystallinity by X-ray diffraction, chemical structure and functional groups by Fourier-transform infrared spectroscopy, thermal stability by thermogravimetric analysis and mechanical properties such as Young s modulus, tensile strength and elongation at beak % of BC.