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Economic, social and environmental factors have led many industries to find new and attractive ways of waste management. Clean biotechnology is an integrated platform for the conversion of wastes into valuable and less toxic end products. Bacterial cellulose (BC) has a long history of its use as an important biomaterial for various applications. However, the potential for its industrialization and commercialization at large scale is still a challenge due to high fermentation cost, low productivity and expensive culture media. To overcome this problem, low-cost substrates and large waste biomass byproducts of various industries have been evaluated for BC production. Of these, tons of wastes produced from the agro, food, brewery and sugar industries, lignocellulosic biorefineries, textile and pulp mills are ideal raw materials for BC production. Recently, various studies have reported the wastes from these industries as a source of various nutrient for the low cost production of BC. This review is centered on BC production from low cost substrates with a major focus on the wastes from agro, food, brewery, sugar industries, lignocellulosic biorefineries, textile and pulp mills. Moreover, recent research trends and commercial media available for BC production are also discussed. This review also discuss briefly the properties and applications of BC. This article would likely draw the attention of researchers towards utilization of industrial wastes as potential alternate media for the production of BC.

Bacterial cellulose (BC) is a pure form of cellulose and has some superior properties such as an ultrafine fiber network, high water-holding capacity and ease of fabrication into a desired shape. It has been widely studied for applications in tissue engineering, wound dressing, artificial skin and protein delivery. In the current study, BC matrices (12 mm diameter) were prepared and evaluated for in vitro release using famotidine and tizanidine as model drugs. The successful drug loading and uniform distribution into the matrices were confirmed through scanning electron microscopy and X-ray diffractrometry. Fourier transform infrared spectroscopy and thermogravimetric analysis revealed the chemical and thermal stability of the BC-drug composites, respectively. The percent drug loading of various matrices was in the range of 18.10–67.64%. Similarly, the friability test results were in the range of 0.69–0.83 and 0.14–0.89% for 20 and 40 mg/ml famotidine (low water soluble) loaded matrices, respectively, while no weight loss was observed in friability tests for formulations loaded with 6 mg/ml tizanidine (highly water soluble) because of the low dose and drug concentration. In vitro dissolution studies showed more than 80% drug release in the initial 15 min for all formulations, conforming to immediate release criteria. Comparison studies were carried out using famotidine and tizanidine commercial tablets. The results of current research work revealed that BC matrices have the potential for applications in single polymer-based oral drug delivery.

Bacterial cellulose (BC) was investigated for the first time for the preparation of capsule shells for immediate and sustained release of drugs. The prepared capsule shells were characterized using X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectroscopy. The BC capsule shells were studied for drug release using an USP type-I dissolution apparatus. Irrespective of the drying method and the thickness of the BC sheet, the capsule shells displayed an immediate drug release profile. Moreover, the addition of release-retardant cellulosic polymers sustained the drug release having first-order kinetics for hydroxypropylmethylcellulose and carboxymethyl cellulose sodium with R 2 values of 0.9995 and 0.9954, respectively. Furthermore, these capsules shells remained buoyant in 0.1 N HCl (pH 1.2) solution up to 12 h. This study showed that BC is a promising alternative to gelatin capsules with both immediate and sustained drug release properties depending upon the compositions of the encapsulated materials.

Physicochemical properties of materials can be amended by altering their physical structure through different processing conditions. The present study was conducted to investigate the post-synthesis structural variations and physico-mechanical properties of bacterial cellulose (BC) sheets prepared using different drying methods. Wet BC sheets of the same origin were freeze dried (BC-FD), dried at room temperature (25 °C) (BC-DRT), and dried at elevated temperature (50 °C) (BC-DHT). FE-SEM micrographs revealed that BC-DRT and BC-DHT had a more tightly packed and compact structure than the loosely held fibrils of BC-FD. XRD analysis revealed the relative crystallinity of the BC sample to be 64.60, 59.16, and 47.20 % for BC-DHT, BC-DRT and BC-FD, respectively. The water holding capacity (WHC) of the BC-FD was higher than that of the other two samples. Four consecutive drying and rewetting cycles demonstrated that the WHC of all samples decreased with each cycle. The WHC of BC-DRT and BC-DHT was reduced to almost 0 after the first drying cycle, but the BC-FD samples were able to regain some of their WHC. The tensile strength and elongation modulus were in the order of BC-DHT > BC-DRT > BC-FD. Overall, the results of this study revealed that the post-synthetic processing conditions had a strong effect on the structure and physico-mechanical properties of BC.

This study was conducted to develop nanocomposite films of bacterial cellulose (BC) and montmorillonite (MMT) with potent antibacterial activity and potential therapeutic value in wound healing and tissue regeneration. Different composites were prepared through impregnation of BC sheets with 2 and 4 % suspensions of MMT, Na-MMT, Ca-MMT and Cu-MMT. These modified MMTs were prepared through cation exchange strategy. The antibacterial activities of the composites were then assessed against Escherichia coli and Staphylococcus aureus through the disc diffusion assay and colony forming unit (CFU) count methods. BC-Cu-MMT composites prepared with 2 and 4 % MMT displayed clear zones of inhibition against E. coli (20 and 22 mm, respectively) and S. aureus (19 and 20.5 mm, respectively). The untainted BC, BC-MMT, BC-Na-MMT and BC-Ca-MMT did not show clear inhibitory zones against the tested organisms. The reduction in CFU observed following treatment with BC-MMTs (BC-MMT, BC-Na-MMT, BC-Ca-MMT and BC-Cu-MMT) prepared using 2 % MMTs suspension was 7.39, 14.8, 19.2 and 77.9 % for E. coli and 6.8, 13.7, 17.4 and 74.1 %, for S. aureus, respectively. When treated with BC-MMT, BC-Na-MMT, BC-Ca-MMT and BC-Cu-MMT prepared with 4 % MMTs suspension, the reduction in CFU increased to 10.58, 18.37, 24.62 and 85.01 % for E. coli and 9.44, 15.73, 20.40 and 79.79 % for S. aureus, respectively. The outcome of this study will facilitate the development of BC sheets as wound dressings and regeneration materials with antibacterial properties for therapeutic applications without any side effects.