Optimization of moist and oven-dried bacterial cellulose production for functional properties

Abstract

Bacterial cellulose (BC) is a natural polymer with properties suitable for tissue engineering and possible applications in scaffold production. However, current procedures have limitations in obtaining BC pellicles with the desired structural, physical, and mechanical properties. Thus, this study analyzed the optimal culture conditions of BC membranes and 2 types of processing: draining and oven-drying. The aim was to obtain BC membranes with properties suitable for a wound dressing material. Two studies were carried out. In the preliminary study the medium (100 mL) was inoculated with varying volumes (1; 2; 3; 4; and 5 mL) and incubated statically for different periods (3; 6; 9; 12; and 18 days), using a full factorial experimental design. Thickness, uniformity, weight, and yield were evaluated. In the optimization study, a Box–Behnken design was used. Two independent variables were used: inoculum volume (X1: 1; 3; and 5 mL) and fermentation period (X2: 6; 12; and 18 d) to determine the target response variables: thickness, swelling ratio, drug release, fiber diameter, Tensile strength, and Young's Modulus for both dry and moist BC membranes. The mathematical modelling of the effect of the 2 independent variables was accomplished by response surface methodology (RSM). The obtained models were validated with new experimental values, and confirmed for all tested properties, except Young Modulus of oven-dried BC. Thus, the optimal properties in terms of a scaffold material of the moist BC were obtained with an inoculum volume of 5% (v/v) and 16 d of fermentation. While, for the oven-dried membranes a 4% (v/v) and 14 d of fermentation.

Bacterial nanocellulose membranes as potential chronic wound dressing: influence of alternative culture media on nanofiber diameter - a brief review

“…Figure 3 shows the alternative culture media used for BNC production. It is possible to note the predominance of kombucha-like culture media (5 papers, 62.5%), which 40% were supplemented with corn syrup (DIMA et al, 2017) or calcium carbonate and yeast extracts (BODEA et al, 2021).…”

“…Similarly, Bodea and collaborators (2021) supplemented the kombucha-like medium with calcium carbonate, despite the reason was not informed in their paper. It was found that the inoculum and fermentation time did not influence the homogeneity of obtained BNC membranes, as well as a two-step effective purification process for BNC (BODEA et al, 2021). Also, nanofibers' average diameter was between 40.6-51.33 nm and the CrI was, unfortunately, not measured.…”

“…Moreover, to optimize the BNC production, some statistical methods such as Design of Experiments (DOE) can also be used, and these methods can positively affect BNC properties, resulting in reproducible nanofiber diameters and CrI (BODEA et al, 2021;ERBAS KIZILTAS;KIZILTAS;GARDNER, 2015). Based on that, CrI and nanofiber diameter might be used as response variables in addition to BNC production yield.…”

Improving the Water Absorption Properties of Bacterial Cellulose by In-Situ and Ex-Situ Modifications for Use in CMC-Graft-Sodium Acrylate Superabsorbent

“…The dense cellulose network led to less water accumulation between fibers, resulting in a 7.83% -26.53% decrease in the BC-CMC initial wet weight compared to the wet weight of BC. According to a study by Bodea et al, the first drying of BC brings the fibers closer together, which leads to a more compact structure [45]. Absorbed water in BC limits the interactions between fibers with the competitive hydrogen-water-cellulose bonds.…”

“…Absorbed water in BC limits the interactions between fibers with the competitive hydrogen-water-cellulose bonds. Water in the BC pellicle is crucial to achieving some mechanical properties since water can serve as a plasticizer [45,46]. Despite the decrease in the initial wet weight of the CMC-BC composite compared to the BC, its rehydration increased by 102.30% (Fig.…”