Effects of bacterial cellulose/thyme essential oil emulsion coating on the shelf life of chilled chicken meat.

BACKGROUND: Bacterial cellulose (BC) is a fiber substance produced by microbial fermentation. It is widely used in the food preservation industry because of its extremely pure texture, high crystallinity and high biocompatibility. In the present study, bacterial cellulose/thyme essential oil (BC/TEO-E) with antibacterial and fresh-keeping functions was prepared by ultrasonic treatment of modified bacterial cellulose for encapsulation of thyme essential oil, which effectively inhibited the spoilage of chilled chicken. RESULTS: The purified BC, produced by Acetobacter xylinum ATCC 53524, was ultrasonically treated wih different times (0, 30, 60 and 90 min). Transmission electron microscopy, scanning electron microscopy, Fourier transformed infrared spectroscopy, X-ray diffraction, differential scanning calorimetry and zeta potential were used to characterize the structure of BC after ultrasound, showing that BC, treated for 30 min, had the optimal fiber structure, crystallinity (85.8%), thermal stability (347.77 °C) and solution stability (-26.63 ± 1.96 mV). BC/TEO-E was prepared by a homogenizer for the preservation of chilled chicken. Optical microscopy indicated that the BC/TEO-E prepared by 0.5% BC had optimal dispersion and stability, and even no delamination was observed in the emulsion. Compared with other groups (control, 0.5% BC and Tween-E), the total number of colonies and coliforms in chilled chicken treated with 0.5% BC/TEO-E was the lowest during the whole storage period (12 days), indicating that it can effectively inhibit bacterial growth. In addition, total volatile base nitrogen (TVB-N), thiobarbituric acid reactive substances, pH and drip loss results showed that 0.5% BC/TEO-E could effectively inhibit the spoilage of chilled chicken compared to the other treatment groups. CONCLUSION: All of the results acquired in the present study indicate that BC/TEO-E has a potential application in chilled chicken preservation. © 2024 Society of Chemical Industry.

Enhanced bacterial cellulose production in Gluconacetobacter xylinus by overexpression of two genes (bscC and bcsD) and a modified static culture.

Bacterial cellulose (BC), a nanostructured material, is renowned for its excellent properties. However, its production by bacteria is costly due to low medium utilization and conversion rates. To enhance the yield of BC, this study aimed to increase BC yield through genetic modification, specifically by overexpressing bcsC and bcsD in Gluconacetobacter xylinus, and by developing a modified culture method to reduce medium viscosity by adding water during fermentation. As a result, BC yields of 5.4, 6.2, and 6.8 g/L were achieved from strains overexpressing genes bcsC, bcsD, and bcsCD, significantly surpassing the yield of 2.2 g/L from wild-type (WT) strains. In the modified culture, the BC yields of all four strains increased by >1 g/L with the addition of 20 mL of water during fermentation. Upon comparing the properties of BC, minimal differences were observed between the WT and pbcsC strains, as well as between the static and modified cultures. In contrast, BC produced by strains overexpressing bcsD had a denser microstructural network and exhibited demonstrated higher tensile strength and elongation-to-break. Compared to WT, BC from bcsD overexpressed strains also displayed enhanced crystallinity, higher degree of polymerization and improved thermal stability.

Improvement in bacterial cellulose production by co-culturing Bacillus cereus and Komagataeibacter xylinus.

Bacterial cellulose (BC) is a bio-produced nanostructure material widely used in biomedical, food, and paper-manufacturing industries. However, low production efficiency and high-cost have limited its industrial applications. This study aimed to examine the level of improvement in BC production by co-culturing Bacillus cereus and Komagataeibacter xylinus. The BC yield in corn stover enzymatic hydrolysate was found to be obviously enhanced from 1.2 to 4.4 g/L after the aforementioned co-culturing. The evidence indicated that acetoin (AC) and 2,3-butanediol (2,3-BD) produced by B. cereus were the key factors dominating BC increment. The mechanism underlying BC increment was that AC and 2,3-BD increased the specific activity of AC dehydrogenase and the contents of adenosine triphosphate (ATP) and acetyl coenzyme A (acetyl-CoA), thus promoting the growth and energy level of K. xylinus. Meanwhile, the immobilization of BC could also facilitate oxygen acquisition in B. cereus under static conditions. This study was novel in reporting that the co-culture could effectively enhance BC production from the lignocellulosic enzymatic hydrolysate.

Cellulose biosynthesis using simple sugars available in residual cacao mucilage exudate.

Worldwide only 8% of the biomass from harvested cacao fruits is used, as cacao beans, in chocolate-based products. Cacao mucilage exudate (CME), a nutrient-rich fluid, is usually lost during cacao beans fermentation. CME's composition and availability suggest a potential carbon source for cellulose production. CME and the Hestrin and Schramm medium were used, and compared, as growth media for bacterial cellulose (BC) production with Gluconacetobacter xylinus. CME can be used to produce BC. However, the high sugar content, low pH, and limited nitrogen sources in CME hinder G. xylinus growth affecting cellulose yields. BC production increased from 0.55 ± 0.16 g L-1 up to 13.13 ± 1.09 g L-1 after CME dilution and addition of a nitrogen source. BC production was scaled up from 30 mL to 15 L, using lab-scale experiments conditions, with no significant changes in yields and production rates, suggesting a robust process with industrial possibilities.

Implantation of air-dried bacterial nanocellulose conduits in a small-caliber vascular prosthesis rabbit model.

There are no small-caliber (<6 mm) vascular prostheses so far commercially available around the globe. Bacterial nanocellulose (BNC) is considered a promising material for small-caliber artificial blood vessel applications. Although BNC hydrogel-like (BNC-Gel) materials possess a 3D network structure, facilitating nutrient exchange when used as vascular prostheses, they are difficult to suture during surgery due to their softness. Furthermore, a water content greater than 99% prevents the material from convenient methods of preservation and transport. Air-drying the BNC (BNC-Dry) would solve these problems. The comparative morphology, mechanical properties, hemocompatibility, and cytocompatibility of the BNC-Gel and BNC-Dry conduits of 3 mm in diameter were recorded in the present study, the results indicating that the mechanical properties, hemocompatibility, and cytocompatibility of BNC-Dry conduits were superior to conduits of BNC-Gel. Forty-six days after replacement of the carotid artery in New Zealand white rabbits, the BNC-Dry conduits remained patent. Composite blood vessels composed of cellulose and autologous tissue were harvested for immunohistochemistry and immunofluorescence staining. Sections demonstrated that the outer walls of the conduits were wrapped with autologous tissue. Contractile smooth muscle cells (SMCs) were observed on the outer surface of the conduit, similar to that observed in natural blood vessels. BNC-Dry conduits exhibited excellent performance and possessed properties convenient for surgical applications as small-diameter blood vessels.

Biotech nanocellulose: A review on progress in product design and today's state of technical and medical applications.

Biotech nanocellulose (bacterial nanocellulose, BNC) is a high potential natural polymer. Moreover, it is the only cellulose type that can be produced biotechnologically using microorganisms resulting in hydrogels with high purity, high mechanical strength and an interconnecting micropore system. Recently, the subject of intensive research is to influence this biosynthesis to create function-determining properties. This review reports on the progress in product design and today's state of technical and medical applications. A novel, dynamic, template-based technology, called Mobile Matrix Reservoir Technology (MMR Tech), is highlighted. Thereby, shape, dimensions, surface properties, and nanonetwork structures can be designed in a process-controlled manner. The formed multilayer materials open up new applications in medicine and technology. Especially medical materials for cardiovascular and visceral surgery, and drug delivery systems are developed. The effective production of layer-structured composites and coatings are important for potential applications in the electronics, paper, food and packaging technologies.

Sustainable, superhydrophobic membranes based on bacterial cellulose for gravity-driven oil/water separation.

Bacterial cellulose (BC) is a substrate material with high purity and robust mechanical strength, but due to its small pore size and relatively expensive price, it is restricted as an oil-/water separation membrane. In this study, cheaper plant cellulose needle-leaf bleached kraft pulp (NBKP) was added to BC to increase the pore size of the composite membrane, and a superhydrophobic/superoleophilic membrane was prepared for oil-/water separation. The modified membrane surface displayed a petal-like micro-structure and a water contact angle (WCA) of 162.3°, while the oil contact angle was decreased to 0°. What's more, the membrane exhibited excellent oil-/water separation under gravity, recyclability, and a separation efficiency (>95 %), and it was both pH and salt resistant. The membrane also remained durably hydrophobic after 10 separation cycles. And the separation methodology is expected to be highly energy-efficient.

In Vitro Study of a Stentless Aortic Bioprosthesis Made of Bacterial Cellulose.

PURPOSE: The paper present findings from an in vitro experimental study of a stentless human aortic bioprosthesis (HAB) made of bacterial cellulose (BC). Three variants of the basic model were designed and tested to identify the valve prosthesis with the best performance parameters. The modified models were made of BC, and the basic model of pericardium. METHODS: Each model (named V1, V2 and V3) was implanted into a 90 mm porcine aorta. Effective Orifice Area (EOA), rapid valve opening time (RVOT) and rapid valve closing time (RVCT) were determined. The flow resistance of each bioprosthesis model during the simulated heart systole, i.e. for the mean differential pressure (ΔP) at the time of full valve opening was measured. All experimental specimens were exposed to a mean blood pressure (MBP) of 90.5 ± 2.3 mmHg. RESULTS: The V3 model demonstrated the best performance. The index defining the maximum opening of the bioprosthesis during systole for models V1, V2 and V3 was 2.67 ± 0.59, 2.04 ± 0.23 and 2.85 ± 0.59 cm2, respectively. The mean flow rate through the V3 valve was 5.7 ± 1, 6.9 ± 0.7 and 8.9 ± 1.4 l/min for stroke volume (SV) of 65, 90 and 110 mL, respectively. The phase of immediate opening and closure for models V1, V2 and V3 was 8, 7 and 5% of the cycle duration, respectively. The mean flow resistance of the models was: 4.07 ± 2.1, 4.28 ± 2.51 and 5.6 ± 2.32 mmHg. CONCLUSIONS: The V3 model of the aortic valve prosthesis is the most effective. In vivo tests using BC as a structural material for this model are recommended. The response time of the V3 model to changed work conditions is comparable to that of a healthy human heart. The model functions as an aortic valve prosthesis in in vitro conditions.

Synthesis and SERS application of gold and iron oxide functionalized bacterial cellulose nanocrystals (Au@Fe3O4@BCNCs).

Bacterial cellulose nanocrystals (BCNCs) are biocompatible cellulose nanomaterials that can host guest nanoparticles to form hybrid nanocomposites with a wide range of applications. Herein, we report the synthesis of a hybrid nanocomposite that consists of plasmonic gold nanoparticles (AuNPs) and superparamagnetic iron oxide (Fe3O4) nanoparticles supported on BCNCs. As a proof of concept, the hybrid nanocomposites were employed to isolate and detect malachite green isothiocyanate (MGITC) via magnetic separation and surface-enhanced Raman scattering (SERS). Different initial gold precursor (Au3+) concentrations altered the size and morphology of the AuNPs formed on the nanocomposites. The use of 5 and 10 mM Au3+ led to a heterogenous mix of spherical and nanoplate AuNPs with increased SERS enhancements, as compared to the more uniform AuNPs formed using 1 mM Au3+. Rapid and sensitive detection of MGITC at concentrations as low as 10-10 M was achieved. The SERS intensity of the normalized Raman peak at 1175 cm-1 exhibited a log-linear relationship for MGITC concentrations between 2 × 10-10 and 2 × 10-5 M for Au@Fe3O4@BCNCs. These results suggest the potential of these hybrid nanocomposites for application in a broad range of analyte detection strategies.

Glioblastoma cell adhesion properties through bacterial cellulose nanocrystals in polycaprolactone/gelatin electrospun nanofibers.

Glioblastoma (GBM), the most common and extremely lethal type of brain tumor, is resistant to treatment and shows high recurrence rates. In the last decades, it is indicated that standard two-dimensional (2D) cell culture is inadequate to improve new therapeutic strategies and drug development. Hence, well-mimicked three-dimensional (3D) tumor platforms are needed to bridge the gap between in vitro and in vivo cancer models. In this study, bacterial cellulose nano-crystal (BCNC) containing polycaprolactone (PCL) /gelatin (Gel) nanofibrous composite scaffolds were successfully fabricated by electrospinning for mimicking the extracellular matrix of GBM tumor. The fiber diameters in the nanofibrous matrix were increased with an increased concentration of BCNC. Moreover, fiber morphology changed from the smooth formation to the beaded formation by increasing the concentration of the BCNC suspension. In-vitro biocompatibilities of nanofibrous scaffolds were tested with U251 MG glioblastoma cells and improved cell adhesion and proliferation was compared with PCL/Gel. PCL/Gel/BCNC were found suitable for enhancing axon growth and elongation supporting communication between tumor cells and the microenvironment, triggering the process of tumor recurrence. Based on these results, PCL/Gel/BCNC composite scaffolds are a good candidate for biomimetic GBM tumor platform.

Development of three-dimensional bacterial cellulose/chitosan scaffolds: Analysis of cell-scaffold interaction for potential application in the diagnosis of ovarian cancer.

Bacterial cellulose (BC) has emerged as a biomaterial for diverse biomedical applications owing to its unique structural, physico-chemical, mechanical, and biological features. Its porous geometry and three-dimensional fibrous structure allow the impregnation of various materials into its matrix. The current study was aimed to fabricate 3D scaffolds of bacterial cellulose and chitosan (BC-Chi) through a one-step ex situ solution impregnation strategy and analyze the scaffold interaction with the ovarian cancer cell lines (A2780). Field emission scanning electron microscopy (FE-SEM) showed successful impregnation of chitosan into the BC matrix. Phase-contrast and confocal microscopy analyses revealed that human ovarian cancer cell lines (A2780) were adhered not only to the surface but deeply infiltrated into the matrix of BC-Chi scaffold. WST-1 assay, histology analysis, and cytoskeleton and nuclear staining showed high viability, proliferation, and infiltration of A2780 cell lines into the scaffold. The RT-PCR analysis revealed a decreased mRNA level of Notch receptors, indicating a strong cell-scaffold interaction. The improved biocompatibility, non-toxicity, and 3D structure of fabricated BC-Chi scaffold justify its potential applications diagnosis of ovarian cancer in vivo.

In situ preparation of bacterial cellulose with antimicrobial properties from bioconversion of mulberry leaves.

It's long been understood that antimicrobial properties are one of the most important function in the field of biomedicine. In this thesis, we introduce a new technique to functionalize bacterial cellulose (BC) with antimicrobial properties by in situ method. We design a series of experiments on hydrolyzing mulberry leaves and exploring the methods of fermenting and purifying to obtain a BC complex with antimicrobial properties. Meanwhile, the anti-bacterial performances of MH-BC (fermented by the mulberry leaves acid hydrolysate fermentation medium) were evaluated with Escherichia coli and Staphylococcus aureus, and the experimental results showed that the MH-BC have excellent anti-bacterial activities. Considering the excellent biocompatibility of MH-BC towards hMSCs, we expect that this antibacterial functional BC composite will find potential applications in biomedicine and regenerative medicine.

Fabrication of bacterial cellulose-collagen composite scaffolds and their osteogenic effect on human mesenchymal stem cells.

Scaffold plays a critical role in stem cell differentiation and tissue regeneration. Composite scaffolds composed of bacterial cellulose (BC) and collagen (Col) in different ratios (1:1, 3:1, 5:1) were fabricated in this study. The composite scaffolds exhibit a well-organized interconnected porous structure, significantly better physical stability than Col scaffold, and more water uptake up to 400%. They were also favorable with cell attachment and growth. After osteogenic induction of umbilical cord blood derived mesenchymal stem cells (UCB-MSCs) for 3 weeks, we found more up-regulated osteogenic markers (collagen type 1, osteocalcin, bone sialoprotein) and significantly elevated proteins and calcium deposition, particularly with BC/Col (5:1) scaffold. When PKH-26 pre-labelled MSC-loaded scaffolds were subcutaneously transplanted in a mouse model, they showed many PKH-26-labelled cells and positive signals of α-smooth muscle actin, for neovascularization in the BC/Col (5:1). The current work demonstrates that our BC/Col composites may be promising as a bone tissue-engineered scaffold.

Assessment of the usefulness of bacterial cellulose produced by Gluconacetobacter xylinus E25 as a new biological implant.

Bionanocellulose (BNC) is a clear polymer produced by the bacterium Gluconacetobacter xylinus. In our current study, "Research on the use of bacterial nanocellulose (BNC) in regenerative medicine as a function of the biological implants in cardiac and vascular surgery", we carried out material analysis, biochemical analysis, in vitro tests and in vivo animal model testing. In stage 1 of the project, we carried out physical and biological tests of BNC. This allowed us to modify subsequent samples of bacterial bionanocellulose. Finally, we obtained a sample that was accepted for testing on an animal model. That sample we define BNC1. Patches of BNC1 were then implanted into pigs' vessel walls. During the surgical procedures, we evaluated the technical aspects of sewing in the bioimplant, paying special attention to bleeding control and tightness of the suture line and the BNC1 bioimplant itself. We carried out studies evaluating the reaction of an animal body to an implantation of BNC1 into the circulatory system, including the general and local inflammatory reaction to the bioimplant. These studies allowed us to document the potential usefulness of BNC as a biological implant of the circulatory system and allowed for additional modifications of the BNC to improve the properties of this new implantable biological material.

Bacterial cellulose production by Acetobacter xylinum ATCC 23767 using tobacco waste extract as culture medium.

In this study, bacterial cellulose (BC) was synthesized by Acetobacter xylinum ATCC 23767 using tobacco waste extract (TWE) as a carbon source. Nicotine was found to be an inhibitory factor for BC synthesis, but it can be removed at pH 9.0 by steam distillation. After removing nicotine, the BC production was 2.27 g/L in TWE prepared with solid-liquid (S-L) ratio at 1:10. To further enhance the BC production, two fermentation stages were performed over 16 days by re-adjusting the pH to 6.5 at 7 days, after the first fermentation stage was completed. Using this two-stage fermentation, the BC production could reach 5.2 g/L. Structural and thermal analysis by FE-SEM, FT-IR, XRD and TGA showed the properties of BC obtained from TWE were similar to that from Hestrin-Schramm (HS) medium. Considering the huge disposal tobacco waste in China, the present study provides an alternative methodology to synthesize BC.

An in vivo biocompatibility study of surgical meshes made from bacterial cellulose modified with chitosan.

Bacterial cellulose modified with chitosan (MBC) is an innovative biomaterial used in regenerative medicine which may potentially improve treatment outcomes mesh for hernia repair surgery by facilitating better absorption in native tissue with less risk of mesh-related infections. The aim of the present study was to evaluate the biocompatibility of mesh based on MBC, and determine whether immunological reactions occur due to hypersensitivity to the implants. Forty five Imp:WIST rats were randomly assigned to be implanted with one of three mesh types: simple polypropylene mesh (n = 15), mesh modified by bacterial cellulose only (n = 15) and MBC mesh (n = 15) and evaluated after one and three months following intramuscular implantation. For MBC mesh, basic toxicological studies, i.e. Acute Dermal Irritation, Intradermal Reactivity and Acute Sensitization (GPMT), were also carried out on 9 Imp:BN albino rabbits and 15 Imp:D-H guinea pigs. The lowest immune response and the highest degree of fibroplasia were observed for MBC mesh both after one and three months after implantation. Toxicological studies classified the tested MBC mesh as a barely perceptible irritant with no signs of sensitization or allergic reactions observed during the studies. The findings indicate that MBC mesh does not irritate, does not sensitize and does not cause hypersensitivity in the implant site, and therefore presents a low risk of provoking such reactions in humans.

Drug release and antioxidant/antibacterial activities of silymarin-zein nanoparticle/bacterial cellulose nanofiber composite films.

Bacterial cellulose (BC) is a biopolymer composed of nanofibers which has excellent film-forming ability. However, BC do not have antibacterial or antioxidant activity, thus limiting the applicability of BC for food and biomedical applications. In this study, flavonoid silymarin (SMN) and zein were assembled into spherical SMN-Zein nanoparticles that could be effectively adsorbed onto BC nanofibers. SMN-Zein nanoparticles greatly changed the wettability and swelling property of BC films due to the formation of nanoparticles/nanofibers nanocomposites. SMN-Zein nanoparticles enhanced the release of sparingly soluble silymarin from the nanocomposite films. The active films showed more effective antioxidant and antibacterial activities as compared with pure BC films and thus were able to protect salmon muscle from deterioration and lipid oxidation. These findings suggest that the nanoparticle/nanofiber composites may offer a suitable platform for modification of BC films with improved drug release properties and biological activities.

Desarrollo de cobertura y su evaluación en el tratamiento de las heridas crónicas / Desenvolvimento de cobertura e sua avaliação no tratamento de feridas crônicas / Development of coverage and its evaluation in the treatment of chronic wounds

Objective. To describe the development of the bacterial cellulose coating with anti-inflammatory Ibuprofen (BC/Ibu) and to evaluate the cicatrization process with its use in patients with chronic wounds of venous and diabetic etiology. Methods. Longitudinal descriptive study. The cellulose membrane, cultivated with bacteria Gluconacetobacter xylinus and with incorporation of Ibuprofen, was used in the treatment of patients with chronic wounds in public health services in a Brazilian municipality. The ideal coverage characteristics were evaluated through physical, chemical and cell proliferation tests. Results. The sample consisted of 14 patients (10 women and 4 men), 8 with venous ulcer, 5 with diabetic foot and one with mixed wound. There was reduction of area and pain in 9 lesions; total healing of 3 wounds; and debridement of the devitalized tissue in 5 wounds with increased area. The use of the membrane was important in the reduction of pain, exudation and ease in the accomplishment of the curative. Conclusion. BC/Ibu favored the cicatrization process of patients with chronic vasculogenic wounds.(AU)

Objetivo. Describir el desarrollo de la cobertura de celulosa bacteriana con antiinflamatorio Ibuprofeno (CB/Ibu) y evaluar el proceso de cicatrización en la utilización en pacientes con heridas crónicas de etiología venosa y diabética. Métodos. Estudio descriptivo longitudinal. La membrana de celulosa, cultivada con bacterias Gluconacetobacter xylinus y con incorporación del Ibuprofeno se utilizó en el tratamiento de pacientes con heridas crónicas en servicios de atención pública de un municipio brasileño. Se evaluaron características de cobertura ideal mediante pruebas físicas, químicas y de proliferación celular. Resultados. La muestra fue constituida por 14 pacientes (10 mujeres y 4 hombres): 8 con úlcera venosa, 5 con pie diabético y uno con herida mixta. Se redujo el área y el dolor en 9 lesiones; la cicatrización total de 3 heridas; y el debridamiento del tejido desvitalizado en 5 heridas con aumento del área. El uso de la membrana de celulosa disminuyó el dolor de la exudación y facilitó la realización del vendaje. Conclusión. La CB/Ibu favoreció el proceso de cicatrización de los pacientes con heridas crónicas vasculogénicas.(AU)

Objetivo. Descrever o desenvolvimento da cobertura de celulose bacteriana com anti-inflamatório Ibuprofeno (CB/Ibu) e avaliar o processo de cicatrização com a sua utilização em pacientes com feridas crônicas de etiologia venosa e diabética. Métodos. Estudo descritivo longitudinal. A membrana de celulose, cultivada com bactérias Gluconacetobacter xylinus e com incorporação do Ibuprofeno, foi utilizada no tratamento de pacientes com feridas crônicas em serviços de atendimento público de um município brasileiro. Foram avaliadas as características de cobertura ideal mediante testes físicos, químicos e de proliferação celular. Resultados. A amostra foi constituída por 14 pacientes (10 mulheres e 4 homens), sendo 8 com úlcera venosa, 5 com pé diabético e um com ferida mista. Houve redução da área e da dor em 9 lesões; cicatrização total de 3 feridas; e o debridamento do tecido desvitalizado em 5 feridas com aumento da área. O uso da membrana além da diminuição da dor, da exsudação e facilidade na realização do curativo. Conclusão. A CB/Ibu favoreceu o processo cicatrização dos pacientes com feridas crônicas vasculogênicas. (AU)

Efficient bioconversion from acid hydrolysate of waste oleaginous yeast biomass after microbial oil extraction to bacterial cellulose by Komagataeibacter xylinus.

Biomass acid hydrolysate of oleaginous yeast Trichosporon cutaneum after microbial oil extraction was applied as substrate for bacterial cellulose (BC) production by Komagataeibacter xylinus (also named as Gluconacetobacter xylinus previously) for the first time. BC was synthesized in static culture for 10 days, and the maximum BC yield (2.9 g/L) was got at the 4th day of fermentation. Most carbon sources in the substrate (glucose, mannose, formic acid, acetic acid) can be utilized by K. xylinus. The highest chemical oxygen demand (COD) removal (40.7 ± 3.0%) was obtained at the 6th day of fermentation, and then the COD increased possibly due to the degradation of BC. The highest BC yield on COD consumption was 38.7 ± 4.0% (w/w), suggesting that this is one efficient bioconversion for BC production. The BC structure was affected little by the substrate by comparison with that generated in classical HS medium using field-emission scanning electron microscope (FE-SEM), Fourier transform infrared, and X-ray diffraction. Overall, this technology can both solve the issue of waste oleaginous yeast biomass and produce valuable biopolymer (BC).

Correlation between type of alkali rinsing, cytotoxicity of bio-nanocellulose and presence of metabolites within cellulose membranes.

The study aimed at evaluation of various types of alkali rinsing with regard to their efficacy in terms of removal, not only of bacteria but also bacterial metabolites, from cellulose matrices formed by three Komagataeibacter xylinus strains. Moreover, we tested the type of alkali rinsing on membrane cytotoxicity in vitro in fibroblast and osteoblast cells and we compared matrices' ability to induce oxidative stress in macrophages. We identified 11 metabolites of bacterial origin that remained in cellulose after rinsing. Moreover, our results indicated that the type of alkali rinsing should be adjusted to specific K. xylinus strains that are used as cellulose producers to obtain safe biomaterials in the context of low cytotoxicity and macrophage induction. The findings have translational importance and may be of direct significance to cellulose dressing manufacturers.