Biosynthesis and characterization of bacteria cellulose–chitosan film

Structure and properties of cellulose film produced by Acetobacto xylinum were modified by the supplement of low-molecular-weight chitosan into the culture medium. With the addition of 0.75% (w/v) chitosan, the films of BC-chitosan (BCC) of MW 30,000 and BCC of MW 80,000 were homogeneous with a significantly denser fibril structure, smaller pore diameter and higher surface area in comparison to those of BC films. The pore sizes of the dried films of BC, BCC of MW 30,000 and BCC of MW 80,000 were 224, 151 and 132 Å, respectively. The FTIR spectra indicated the intermolecular interaction between BC and chitosan. The mechanical properties and the water absorption capacity of films were significantly improved by 1.4–1.6 and 1.3–1.4-folds, respectively. However, the addition of chitosan of low-molecular-weight in the dilute concentration as in this study showed no significant influence on some properties of the films such as water vapor transmission rates, average crystallinity index and anti-microbial ability.