Bacterial Cellulose and Pullulan from Simple and Low Cost Production Media

Bio-synthesis of bacterial cellulose from ramie textile waste for high-efficiency Cu(II) adsorption

The current study aims at the high-value utilization of ramie textile waste and explores a bio-synthetic pathway to convert waste ramie fibers into bacterial cellulose (BC). Ramie fibers were treated with commercial cellulase (C2730) and the hydrolysate was used as a base medium (RFH) for BC synthesis by fermentation. The enzymatic hydrolysis parameters were optimized by response surface methodology, yielding an optimal temperature of 40 °C, 64 h, and an enzyme dosage of 5.7%. Under these optimized conditions, the resultant yield of reducing sugars was 31.24 ± 0.37 g/L. And then the Novacetimonas hansenii HX1 strain isolated from kombucha was used for fermentation production of BC. The study found that adding yeast extract into RFH can significantly increase BC production, and 7.2 g/L BC can be produced within 7 days. The physical and chemical properties of BC were then analyzed, including Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Thermogravimetric analysis (TGA), confirming its type Iα cellulose structure and good thermal stability. In particular, BC shows efficient adsorption capacity for Cu(II) ions in aqueous solution, with the highest adsorption efficiency reaching 95.62%. This research not only provides a new way to recycle textile waste, but also lays the foundation for the application of BC in the field of environmental remediation.

Response surface methodology and artificial neural network based media optimization for pullulan production in Aureobasidium pullulans

The selection and optimization of carbon and nitrogen sources are essential for enhancing pullulan production in Aureobasidium pullulans. In this study, combinations of carbon (sucrose, fructose, glucose) and nitrogen sources ((NH4)2SO4, urea, NaNO3) were screened, where sucrose and NaNO3 offered the highest pullulan yield (9.33 g L-1). Plackett-Burman design of experiment identified KH2PO4, NaCl, and sucrose as significant factors, which were further optimized using a central composite design. A hyperparameter-optimized artificial neural network (ANN) model with a 3-6-2-1 architecture demonstrated superior predictive accuracy (R2: 0.96) and generalizability (R2CV: 0.74) over a reduced quadratic model (R2: 0.82). The predicted pullulan yield (31.9 g L-1) under ANN model optimized conditions (sucrose: 79.9 g L-1, KH2PO4: 0.25 g L-1, NaCl: 4.3 g L-1) closely matched with the observed yield (30.17 g L-1), while quadratic model showed a significant deviation (39.7 g L-1 vs. 21.0 g L-1), highlighting the reliability of the ANN model.

Bacterial Nanocellulose Hydrogel: A Promising Alternative Material for the Fabrication of Engineered Vascular Grafts

Blood vessels are crucial in the human body, providing essential nutrients to all tissues while facilitating waste removal. As the incidence of cardiovascular disease rises, the demand for efficient treatments increases concurrently. Currently, the predominant interventions for cardiovascular disease are autografts and allografts. Although effective, they present limitations including high costs and inconsistent success rates. Recently, synthetic vascular grafts, made from artificial materials, have emerged as promising alternatives to traditional methods. Among these materials, bacterial cellulose hydrogel exhibits significant potential for tissue engineering applications, particularly in developing nanoscale platforms that regulate cell behavior and promote tissue regeneration, attributed to its notable physicochemical and biocompatible properties. This study reviews recent progress in fabricating engineered vascular grafts using bacterial nanocellulose, demonstrating the efficacy of bacterial cellulose hydrogel as a biomaterial for synthetic vascular grafts, specifically for stimulating angiogenesis and neovascularization.

Advanced "Green" Prebiotic Composite of Bacterial Cellulose/Pullulan Based on Synthetic Biology-Powered Microbial Coculture Strategy

Bacterial cellulose (BC) is a biopolymer produced by different microorganisms, but in biotechnological practice, Komagataeibacter xylinus is used. The micro- and nanofibrillar structure of BC, which forms many different-sized pores, creates prerequisites for the introduction of other polymers into it, including those synthesized by other microorganisms. The study aims to develop a cocultivation system of BC and prebiotic producers to obtain BC-based composite material with prebiotic activity. In this study, pullulan (PUL) was found to stimulate the growth of the probiotic strain Lactobacillus rhamnosus GG better than the other microbial polysaccharides gellan and xanthan. BC/PUL biocomposite with prebiotic properties was obtained by cocultivation of Komagataeibacter xylinus and Aureobasidium pullulans, BC and PUL producers respectively, on molasses medium. The inclusion of PUL in BC is proved gravimetrically by scanning electron microscopy and by Fourier transformed infrared spectroscopy. Cocultivation demonstrated a composite effect on the aggregation and binding of BC fibers, which led to a significant improvement in mechanical properties. The developed approach for "grafting" of prebiotic activity on BC allows preparation of environmentally friendly composites of better quality.

Bacterial cellulose and its potential for biomedical applications

Bacterial cellulose (BC) is an important polysaccharide synthesized by some bacterial species under specific culture conditions, which presents several remarkable features such as microporosity, high water holding capacity, good mechanical properties and good biocompatibility, making it a potential biomaterial for medical applications. Since its discovery, BC has been used for wound dressing, drug delivery, artificial blood vessels, bone tissue engineering, and so forth. Additionally, BC can be simply manipulated to form its derivatives or composites with enhanced physicochemical and functional properties. Several polymers, carbon-based nanomaterials, and metal nanoparticles (NPs) have been introduced into BC by ex situ and in situ methods to design hybrid materials with enhanced functional properties. This review provides comprehensive knowledge and highlights recent advances in BC production strategies, its structural features, various in situ and ex situ modification techniques, and its potential for biomedical applications.