Civil Engineering Reference
In-Depth Information
and bioactive compounds carriers [126]. For instance, Kirdponpattara and Phisalaphong
[126] fabricated a BC/alginate sponge by freeze drying and used it as a yeast carrier for
ethanol fermentation. h e results of a 15 cycle repeated batch operation indicated that
the system with immobilized yeast culture in the BC/alginate nanocomposite showed
superior long-term stability for ethanol fermentation with an average production of
1.9 g.L
-1
and an immobilized yield of 86% (Figure 2.15). h ese promising outcomes
were attributed to the water uptake ability and properly interconnected pore structure
of the nanocomposite that contribute to overcome limiting mass transfer.
A class of nanocomposites i lms based entirely on microbial polysaccharides, BC
and pullulan were developed [127] by casting water-based suspensions of pullulan and
BC. All nanocomposites displayed improved thermal stability and mechanical proper-
ties, compared to the neat pullulan i lm, as supported by signii cant increases in the
degradation temperature (up to 40ºC) and on both Young modulus and tensile strength
(up to 100 and 50% for i lms not plasticized with glycerol), respectively. In addition,
all i lms were highly translucent and could i nd application as organic electronics, dry
food packaging and in biomedical applications.
Collagen, silk i broin, i brin and gelatin, have also been explored for the develop-
ment of novel protein/BC biocomposites for biomedical applications. One of the i rst
works in this domain aimed at improve the promising features of BC as wound dressing
by incorporating collagen type I into the BC membrane during
in situ
formation [128].
h is nanocomposite material was able to reduce expressively the amount of selected
proteases and interleukins typically present in nonhealing exudates and possessed a
distinct antioxidant capacity as well. Luo
et al.
[129] also described the biosynthesis
of a collagen/BC nanocomposite by adding collagen to the culture medium and stud-
ied its morphology and structure. h is collagen/BC nanocomposite showed a more
Figure 2.15
SEM images of cross-section and surface of native BC/alginate carrier 0 h (A and C) and
at er 72h batch fermentation (C and D). Reproduced with permission from [126].
