Functionalization of Bacterial Cellulose Filaments for Knitting Responsive Textiles

New biocomposites based on thermoplastic starch and bacterial cellulose

Cellulose is one of the most abundant polymers on the earth's surface and is often used as the main raw material in various industries. Bacterial Cellulose (BC) is an organic compound produced by certain types of bacteria with various variations and combinations of substrates, including coconut water, rice soaking water, tomatoes, and a mixture of tomato-rice water, coconut-tomato water, and coconut water-rice water. This study aims to determine the optimization of BC formation in various variations and combinations of substrates with organoleptic and physical tests on each sample. This study used experimental methods on each substrate and analyzed descriptively qualitatively. The formula for making BC was 50 mL of each substrate, 5 grams of sugar, 2 grams of ZA (ammonium sulfate), 2 grams of glacial acetic acid, and 2 mL of starter (Acetobacter xylinum). The results of this study obtained organoleptic BC by 90% of panelists liked it, and 10% of panelists disliked it. Meanwhile, the best optimization of BC production obtained the highest thickness and yield on the coconut-rice water substrate treatment of 2.3 cm and 80% yield, the highest water content on the coconut water, coconut-tomato water, and coconut-rice water substrate treatments, respectively, each of 97% and the highest fiber content in rice water, tomato water, and tomato-rice water substrates were 3% each.

Mannose constitutes a principal component in numerous biomass hemicelluloses; however, its utilization by the cellulose-producing bacterium Komagataeibacter xylinus is inefficient. Consequently, during biorefinery and the transformation of biomass rich in mannose for the production of the high-value biological product, bacterial cellulose (BC), the biomass components cannot be fully utilized, leading to resource wastage. Moreover, inappropriate discharge of the fermentation effluent may also result in environmental pollution. This study addressed the underutilization of mannose in spent coffee grounds (SCGs) by introducing a fusion vector expressing mannokinase and phosphomannose isomerase into K. xylinus ATCC 23770, thereby enhancing mannose utilization in this strain model. SCG was pretreated with concentrated sulfuric acid to disrupt crystalline structures, followed by enzymatic hydrolysis to extract saccharides. When culturing in SCG hydrolysate, BC pellicle-derived inoculum achieved 1.2-fold higher BC yield than broth inoculum, attributed to BC matrix protection. The engineered strain K. xylinus CGMCC 31806 demonstrated superior mannose assimilation, yielding 1.5-fold more BC than wild type in simulated SCG medium. In authentic SCG medium without extra nitrogen addition, BC production reached 3.80 g/L, a 1.2- to 2.5-fold increase. The obtained BC exhibited enhanced mechanical properties with 40-84% higher tensile strength and 20-75% increased Young's modulus. This study validates a dual strategy combining agro-waste valorization and targeted strain modification, establishing a collaborative optimization framework linking biomass feedstocks, microbial engineering, and bioprocessing for cost-effective BC production. Future research would utilize existing commercial high-yield strains to replicate the expression strategy of this fusion protein, in order to achieve truly efficient industrial production.IMPORTANCEThe inefficient utilization of mannose, a major hemicellulose component prevalent in biomass by Komagataeibacter xylinus represents a significant bottleneck in the sustainable, cost-effective bioproduction of bacterial cellulose (BC). This underutilization would lead to wasted resources and potential environmental pollution from fermentation effluents. The study directly addresses this critical challenge by pioneering a synergistic "Feedstock-Strain-Process" integration strategy in advancing BC industrialization. We demonstrate the significant impact of engineering K. xylinus for enhanced mannose assimilation coupled with optimized biorefinery of agro-industrial waste, taking mannose-rich spent coffee grounds, as the representative raw material. This integrated approach not only valorizes abundant agricultural waste streams significantly boosting BC yields under nutrient-limited conditions but also generates BC with superior mechanical properties. The study establishes an actionable blueprint for advancing BC industrialization through collaborative optimization of biomass feedstocks, targeted microbial engineering, and process innovation, aligning with the goals of the circular bioeconomy and sustainable material production.

Bacterial cellulose has high strength and crystallinity, and as such has been suggested as a strategically-useful material that could form the reinforcement phase in composites. In addition to any property improvement, if a biodegradable matrix is reinforced with bacterial cellulose, the entire system should be biodegradable. However, bacterial cellulose is not easily dispersed and thus has not been widely used in such composites. Investigations into the production of bacterial cellulose composites where the cellulose reinforcement component is evenly dispersed is therefore of benefit. Bacterial cellulose can be produced in high quantities by the bacterium Gluconacetobacter xylinus in various media and under various reaction conditions, however altering the growth conditions has been shown to change the yield and properties of the resulting cellulose. Poly-3-hydroxybutyrate (PHB) is a bioplastic that has been hypothesised as a material that could replace traditional plastics, however it is very stiff and brittle. It is possible that its use in a composite with an effective reinforcing phase could improve these properties. Therefore this material was selected as a matrix material to be blended with bacterial cellulose. The examination of growth conditions in this work led to a methodology by which high amounts of cellulose with high crystallinity could be obtained. In addition, methods were determined by which to achieve modified cellulose fibrils. These modifications included cellulose fibrils produced with PHB physically attached to the surface. Solution blending and melt blending techniques were investigated as ways of producing PHB/bacterial cellulose composites. Solution blending was found to produce composites with well dispersed bacterial cellulose, however melt blending was found to degrade samples. It was found that solution blends using cellulose in a ground powder form did not achieve improved properties; however a composite with cellulose in its fibrillar form achieved improved tensile strength and modulus. PHB/bacterial cellulose composites with cellulose in its fibrillar form were produced by dispersing the cellulose fibrils by sonication. Sonication was investigated as a method of harvesting and dispersing bacterial cellulose fibrils in various solvents, including chloroform which could directly dissolve PHB, however only small weights of individual fibrils were obtained in this way. The composite with improved mechanical properties contained 2 wt% cellulose; however it was found that these improvements were observed only if the cellulose was retained in a hydrated never-dried state. Investigations into the biodegradability of PHB and a PHB/bacterial cellulose composite revealed that the composite degraded at a greater rate than neat PHB. This indicates that a bacterial cellulose reinforcement phase is able to assist a PHB matrix to degrade at a faster rate when submerged in compost. It is apparent that techniques can be developed to use bacterial cellulose successfully to confer strength to composites when used as a reinforcing material, as well as increasing the rate of biodegradation of a PHB matrix. Composites of these materials should therefore be considered in the design of biodegradable materials.

Bacterial cellulose (BC) is a non-toxic, high-purity, and biocompatible polymer that is abundant in various bacteria and does not contain lignin, hemicellulose and pectin found in plant cellulose. High concentrations of carbon sources can limit yields of BC. One potential solution to enhance BC production is the use of elicitors like plant extracts; however, the use of plant extracts such as Aloe vera leaf extract remains limited. Therefore, the current study aimed to investigate the effects of Aloe vera leaves on BC properties, glucose consumption, and synthesis rate by Komagataeibacter xylinus to increase BC volumetric production. Aloe vera extract was incorporated into the culture medium (given the conditions used), and BC was analyzed after 5 to 7 days of fermentation. The fermentation process at 30°C showed that increasing Aloe vera extract volume to 30% (v/v) improved glucose consumption, resulting in 3.35 g/L of BC accumulated in culture flasks. Adding different amounts of Aloe vera leaf extracts to the bacteria culture altered the morphology of the BC film and trapped Aloe vera extract inside the BC fibers. The treatment with 30% (v/v) Aloe vera leaf extract also resulted in a less homogeneous Aloe-BC morphological surface structure. The X-ray diffractometer (XRD) crystallinity index of control BC improved from 83.70% to 93.70% compared to the 30% Aloe-BC. According to the IR spectral analysis, the presence of amine groups in dried BC samples is confirmed by the detected absorption in the 1536-1635 cm⁻¹ range, which indicates N–H bending vibrations. In conclusion, including Aloe vera leaf increased glucose intake, enhanced BC biomass, and altered the shape of the BC.

Preparation and characterization of reinforced papers using nano bacterial cellulose

Utilization of acetate buffer to improve bacterial cellulose production by Gluconacetobacter xylinus

Bacterial cellulose and bacterial cellulose-vaccarin membranes for wound healing

Impregnation of silver nanoparticles into bacterial cellulose for antimicrobial wound dressing

Some bacterial strains such as Komagataeibacter xylinus are able to produce cellulose as an extracellular matrix. In comparison to wood-based cellulose, bacterial cellulose (BC) holds interesting properties such as biodegradability, high purity, water-holding capacity, and superior mechanical and structural properties. Aiming toward improvement in BC production titer and tailored alterations to the BC film, we engineered K. xylinus to overexpress partial and complete bacterial cellulose synthase operon that encodes activities for BC production. The changes in cell growth, end metabolite, and BC production titers from the engineered strains were compared with the wild-type K. xylinus. Although there were no significant differences between the growth of wild-type and engineered strains, the engineered K. xylinus strains demonstrated faster BC production, generating 2-4-fold higher production titer (the highest observed titer was obtained with K. xylinus-bcsABCD strain producing 4.3 ± 0.46 g/L BC in 4 days). The mechanical and structural characteristics of cellulose produced from the wild-type and engineered K. xylinus strains were analyzed with a stylus profilometer, in-house built tensile strength measurement system, a scanning electron microscope, and an X-ray diffractometer. Results from the profilometer indicated that the engineered K. xylinus strains produced thicker BC films (wild type, 5.1 μm, and engineered K. xylinus strains, 6.2-10.2 μm). Scanning electron microscope revealed no principal differences in the structure of the different type BC films. The crystallinity index of all films was high (from 88.6 to 97.5%). All BC films showed significant piezoelectric response (5.0-20 pC/N), indicating BC as a promising sensor material.

Engineering PTS-based glucose metabolism for efficient biosynthesis of bacterial cellulose by Komagataeibacter xylinus

Bacterial cellulose (BC) is high purity and several current potential uses in industries. Liquid byproduct of sweet corn canning process (SC) contains fermentable sugars which could be utilized to get higher economic benefits. Therefore, this research aimed to produce BC from SC by Gluconacetobacter xylinus under static condition and use it to improve mechanical properties of natural rubber. The ratio of SC to coconut juice for cellulose production was studied. The result revealed that production yield, water holding capacity and tensile strength of BC produced from the medium containing coconut juice to SC at a ratio of 75:25 (w/w) supplemented with 1% acetic acid, 1% ammonium sulfate and 5% sucrose (w/w) was not significant different from BC obtained from a coconut juice medium. The FTIR spectra of BC showed the characteristics of cellulose. The morphology of BC exhibited high fibril network. BC is showed reinforcement in natural rubber composites due to enhance the stress value, whereas reduce the strain value.

Production of bacterial cellulose membranes in a modified airlift bioreactor by Gluconacetobacter xylinus

Effects of different hydrocolloids on the production of bacterial cellulose by Acetobacter xylinum using Hestrin–Schramm medium under anaerobic condition

Antarctic microorganisms have developed extraordinary strategies for adaptation. They have also demonstrated the ability to produce various biopolymers in response to environmental stress. The demand for biopolymers is constantly increasing and is expected to grow further. Among emerging biomaterials, bacterial cellulose (BC) is generating significant interest due to its unique characteristics that distinguish it from plant-based cellulose. BC exhibits higher purity, water-holding capacity, and tensile strength compared to its plant-based counterpart. Furthermore, BC can be obtained through environmentally friendly protocols. Several bacterial strains have already been identified as cellulose producers, including Komagataeibacter xylinus. In this study, a marine bacterial strain named Pseudomonas sp. ef1, isolated from a consortium associated with the Antarctic ciliate Euplotes focardii, was tested for cellulose production. We found that this Antarctic Pseudomonas can produce BC in conditions that appear unique to this bacterial strain. Furthermore, the final BC product is structurally different from that obtained from the well-known BC producer Komagataeibacter xylinus. Additionally, a putative cellulose synthase was identified from the Pseudomonas sp. ef1 genome, exhibiting unique characteristics that may account for the unique BC production capability of this Antarctic marine Pseudomonas. The versatility of BC opens numerous applications, including in papermaking, food, pharmaceutical, and biomedical sectors.