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Communication

Biofabricating Three-Dimensional Bacterial Cellulose Composites Using Waste-Derived Scaffolds

1
Advanced Ceramics, Universität Bremen, 28359 Bremen, Germany
2
School of Product Design, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand
3
MAPEX—Center for Materials and Processes, University of Bremen, 28334 Bremen, Germany
4
Biomolecular Interaction Centre, University of Canterbury, Christchurch 8140, New Zealand
*
Author to whom correspondence should be addressed.
Current address: School of Architecture & Product Design, University of Limerick, V94 T9PX Limerick, Ireland
Appl. Sci. 2025, 15(12), 6396; https://doi.org/10.3390/app15126396
Submission received: 15 April 2025 / Revised: 29 May 2025 / Accepted: 29 May 2025 / Published: 6 June 2025

Abstract

:
Microorganisms metabolising low-value carbon sources can produce a diverse range of bio-based and biodegradable materials compatible with circular economy principles. One such material is bacterial cellulose (BC), which can be obtained in high purity through the fermentation of sweetened tea by a Symbiotic Culture of Bacteria and Yeast (SCOBY). In recent years, there has been a growing research interest in SCOBYs as a promising solution for sustainable material design. In this work, we have explored a novel method to grow SCOBYs vertically using a waste-based scaffold system. Waste sheep wool and cotton fabric were soaked in a SCOBY infusion to serve as scaffolds, carrying the infusion and facilitating vertical growth through capillary forces. Remarkably, vertical membrane growth up to 5 cm above the liquid–air interface (LAI) was observed after just one week. Membranes with different microstructures were found in sheep wool and cotton, randomly oriented between the scaffold fibre, resulting in a high surface area. This study demonstrated that vertical growth in scaffolds is possible, proving the concept of a new method of growing composite materials with potential high-value applications in biomedicine, energy storage, or filtration.

1. Introduction

Today, the world faces significant challenges that demand quick and sustainable solutions. Key challenges include resource shortages due to overexploitation [1] and waste of valuable resources that end up in landfills [2]. There is an urgent need to develop innovative materials that are sustainable and use some of the valuable materials that end up in landfills.
It has been shown that the metabolism of microorganisms and fungi can be harnessed to convert various carbon sources including waste into innovative materials; one such material is Bacterial Cellulose (BC) [3,4,5,6]. BC, a material stronger than steel at the nanoscale [7], stands out as, compared to plant cellulose, BC is purer, mechanically stronger due to its highly polymerised and crystalline structure, and requires less processing, making it more cost-effective and versatile for a wide range of applications [8]. It has been reported that nanocellulose also has resistance to environmental moisture and can enhance water resistance of films, making it a suitable candidate for usage in food packaging [9,10].
A promising approach to producing BC involves is using Symbiotic Cultures of Bacteria and Yeast (SCOBYs), constituting a diverse consortium of microorganisms, particularly acetic acid bacteria and osmophilic yeast.
Traditionally, SCOBYs are associated with kombucha production, a fermented tea beverage originating from China [11]. During fermentation, yeast metabolises sucrose into glucose, fructose, and ethanol, while acetic acid bacteria convert glucose into organic acids, leading to the formation of a nanostructured cellulose biofilm [12,13,14]. Bacterial cellulose synthesis involves the polymerisation of D-glucopyranose units via β-1,4-glycosidic bonds, resulting in macromolecules with degrees of polymerisation ranging from 4000 to 10,000. These polymer chains self-assemble into fibrils via hydrogen bonds, which further organise into ribbons with a length of about 80 nm and a diameter of 4 nm [15]. Due to hydrogen bonding, these ribbons form densely packed fibres, which reach crystallinities between 84–90%. These fibres have lengths in the micrometre range and diameters in the nanometre range, with a length/diameter ratio of about 500. Interfibrillar entanglement and β-1,4-glycosidic bonds form a highly porous and cross-linked network, resulting in a hydrogel with a minimum water content of 98% [7,15,16].
Research into SCOBYs has exponentially increased over the last 20 years, as indicated by the Scopus analysis of publications containing the keywords “SCOBY” or “kombucha”. This rising research interest in SCOBYs mirrors the popularity of healthy, unprocessed, probiotic foods [12,17]. The main research application fields include the optimisation of beverage production, enhancing health benefits, developing new food recipes and supplements, food packaging, composites with nanocellulose, medical composites incorporating metal ions, biomedical materials, 3D tissue engineering, textiles, sustainable leather alternatives, filtration systems, cosmetics, smart materials, sensors, and electrically active materials or conductors as reviewed in detail by Aung et al. [18] and Dutta et al. [11]. Additionally, new applications are being investigated, such as self-cooling materials [19], joule heating elements [20], random lasers with ZnO bionanocomposite foam [21], and aerogels [22].
As is often the case in materials science, research outpaces actual commercial implementation. Despite the growing interest and research in BC, available products made from BC, and more precisely SCOBYs, consist of design prototypes and do-it-yourself projects (see Figure 1). The focus appears to be creating/using these materials as leather or textile alternatives. However, while research into leather alternatives developed from BC is widespread, much less investigation is being performed on grown composite materials.
Most such composites involve the horizontal growth of SCOBY into thin sheets, but these frequently exhibit delamination and inhomogeneity. A way to solve this issue is to reinforce BC with fabrics during SCOBY growth; horizontal reinforcement of SCOBY has been examined by [29,30].
Despite this growing interest in SCOBYs, there has been little research into the vertical growth of the SCOBY within a fibre scaffold. In this work, we present our work addressing the gap in research in SCOBY material by investigating the vertical growth approach of SCOBY composites using scaffolds.
Using the vertical growth approach could mitigate some common issues with grown SCOBY composites like delamination and would enable innovative design opportunities in terms of shape and dimensions, potentially opening new application fields. The main aim of this work is to examine the feasibility of vertical growth of SCOBYs to create composites using local waste streams. We considered local waste in the Canterbury region, and two specific waste streams were selected for this study: sheep wool and cotton fabric.

2. Materials and Methods

2.1. Scoby Culture

Black tea was prepared using two tea bags (5 g) per litre of water (Bell Tea, Jacobs Douwe Egberts NZ, Auckland, New Zealand) by stirring the mixture at 100 °C for 10 min. A total of 100 g/L of household sugar (Bonsucro®, Auckland, New Zealand) was added under magnetic stirring at 200 rpm until completely dissolved. After the liquid cooled to room temperature (21 ± 2 °C), 100 mL/L inoculum of a homegrown SCOBY prepared using similar conditions was added and gently mixed. The mixture was then incubated in ambient conditions at 21 ± 2 °C and a relative humidity of approximately 50% for 14 days as a starter culture.

2.2. Growing Using Scaffolds

The dipping-in approach was used to examine if BC forms in vertical fibrous scaffolds. In this approach, scaffolds were vertically hung in a 50 mL tube (Falcon®, Corning, NY, USA) with only the bottom part of the scaffold dipped in the inoculated SCOBY and incubated at room temperature (see Figure 2).
To create the scaffolds, textile samples (sheep wool felt and cotton fabric) were cut into 10 × 2.5 cm strips, sewn on the top edge using cotton yarn, leaving the thread edges (see Figure 2B) to suspend the scaffolds in 50 mL Falcon tubes with a tape (see Figure 2C). The cotton fibre fabric was sourced from the material collection at the School of Product Design, University of Canterbury, New Zealand, and waste sheep wool felt was obtained from discarded packaging waste (Woolpack by Planet Protector, Auckland, New Zealand). The cotton fabric was a plain weave with a thickness of 0.689 mm, a roughened surface, a density of 0.248 g/cm3, and a fibre diameter of 16.13 µm. The sheep wool felt has a thickness of 8.003 mm, a density of 0.048 g/cm3, and a fibre diameter of 34.65 µm. With an absorption capacity of 436.31% for water and 441.06% for kombucha infusion in cotton and 426.09% for water and 405.38% for kombucha infusion in wool felt, no significant difference in absorption capacity was observed between the two materials. These samples will be referred to as DipCo and DipShe, indicating the reinforcement (Co = cotton; She = sheep wool) and a number indicating the week of incubation. Scaffolds were autoclaved in a front-loading benchtop autoclave (3870ELD-C, 85 L, Thermo Fisher Scientific Inc., Waltham, MA, USA) at 120 °C for 15 min prior to addition of infusion inoculate.
All fermentation processes were carried out under sterile conditions in a laminar flow hood. A total of 7.5 mL of the infusion was added to the cotton samples and shaken until they were soaked with liquid completely. The Falcon tubes were filled to the top and left for 5 min to ensure complete wetting of the sheep wool samples placed in them. The tubes were stored vertically in racks with the lids on top but unsealed for measurements in the period of time from 1 to 6 weeks. After three weeks, 5 mL sweetened tea prepared as the starter culture (5 g/L tea, 100 g/L sugar) was added to each sample and the Falcon tubes were turned around to ensure the whole fabric was wet. This step allowed the reinforcement materials to reabsorb moisture, ensuring uniform hydration while also revealing the effects of shear forces and liquid movement on growth. All samples were weighed dry before and after the fermentation using a precision balance (FZ-500i, 520 g × 0.001 g, A&D Co., Tokyo, Japan) to analyse the extent of SCOBY growth. The growth was assumed to be the difference between these values. The yield y was calculated using the growth of SCOBY related to the volume of inoculum used:
y = m g r o w t h V i n o c u l u m
The fibre-to-matrix ratio was calculated using the following:
f m = m d r y w e i g h t   f a b r i c m g r o w t h 100 %
The yield was tested for normal distribution with RStudio (Build 2022.12.0+353) using the Shapiro–Wilk test (2 < n < 4) with a safety margin of α = 0.5. In addition, all test series, except for dip-in sheep wool felt samples (DipShe)—4 weeks, are above α = 0.5; therefore, a normal distribution is assumed. Boxplots were created to provide an overview of the variability, the spread, and the trend to compare the yield over different weeks. A linear regression was performed to determine if there was a trend in the yield over the weeks. To compare the yield distributions between cotton and sheep wool samples, a Mann–Whitney U-test was conducted with α = 0.05. Due to small sample sizes, a non-parametric approach was chosen to compare yield across different growth periods (weeks). The Kruskal–Wallis test was used to assess significant differences (p ≤ 0.05), and pairwise differences were further examined using Dunn’s post hoc test.

2.3. Visual Analysis

The morphology of the SCOBY membranes was analysed using light microscopy and a scanning electron microscope (SEM). The morphology of samples were investigated at the liquid–air interface (LAI) and at distances of 7, 5, 3, and 1 cm above the LAI, as well as 1 cm below it, with a Primostar3 optical microscope (Carl Zeiss Microscopy GmbH, Jena, Germany). SEM was performed using a JEOL JSM (model IT300-LV, Tokyo, Japan). The samples were cut 1 cm above the LAI with scissors and glued vertically and horizontally to the sample holders with carbon tape. Samples were then coated with gold at a current of 20 mA using an EMS150T ES coater (Electron Microscopy Science, Hatfield, PA, USA). The images were recorded at acceleration potential of 15 kV.

3. Results

The dip-in tests were aimed to evaluate whether a SCOBY grows vertically along the liquid–air interface (LAI). The setup ensured that the fabrics were thoroughly saturated with the infusion at the start of the experiment and stayed moist throughout the incubation time. Microscopy was used to evaluate the growth morphology of BC membranes and assess the feasibility of vertical SCOBY growth among the fibres of scaffold materials. Samples incubated for one to six weeks were tested periodically to determine an optimal growth period.
From week one, the growth of BC membranes was confirmed on the LAI, indicating that the culture was healthy and that the consortia could produce nanocellulose. Optical microscopy at different heights above the LAI of the samples revealed biofilm growth in the form of thin membranes between the fibres as early as week 1 in the sheep wool and cotton samples, already proving vertical growth (see Figure 3).
DipShe showed membranes up to 3 cm above and even below the LAI. The Shapiro–Wilk test for DipShe confirmed that all yield values, except for week 4, were normally distributed. A linear regression resulted in R2 = 0.14 and p = 0.083, indicating no significant linear trend. The Dunn’s post hoc test only found a significant difference between week 3 and 5 (adjusted p = 0.000603). This absence of a trend is also visible in Figure 4 and is further evident when comparing the growth and yield from week 1 to week 6 (see Table S1). Notably, the highest yield was observed after three weeks.
In DipCo, membranes were observed from week one, extending across the samples up to 5 cm above the LAI. By the third week of fermentation, these membranes extended up to 7 cm above the LAI. However, this phenomenon was no longer observed after remoistening at week four’s beginning. Like DipShe, the boxplots show high variability and no significant trend in yield, as confirmed by the linear regression with R2 = 0.011 and p = 0.64. The highest yield was found after two weeks of fermentation (see Figure 4), which was significantly different from week 1 (adjusted p = 0.00212). Additionally, a trend toward significant differences was observed between week 2 and all subsequent weeks. The yield in the sheep wool samples appears higher than in the cotton samples and the Mann–Whitney U Test showed a significant difference between the distributions of DipShe and DipCo with p = 0.000000388.

3.1. DipShe

SEM images showed that the sheep wool felt was covered by a continuous layer of BC membrane on the surface during SCOBY growth (see Figure 5). Membrane fragments were observed to be attached to fibres below the surface, indicating membrane growth throughout the whole felt. Week four samples exhibited reduced membrane formation, covering only the scaffold’s surface. This phenomenon may be related to the remoistening process performed after three weeks which could have altered the morphology of the BC film.
The wool fibre surface has been shown to have hydrophobic properties due to the monolayer fatty acids on the outer layer of wool fibres [31], which makes wool a compatible fibre with hydrophobic polymers. Despite this hydrophilicity of the wool fibres and nanocellulose fibres having a hydrophilicity, scanning electron microscopy revealed that the nano cellulose membrane clearly interacts with wool fibres by forming membrane between wool fibres (Figure 6A), wrapping around single fibres of wool (Figure 6B), and covering the wool fibres (Figure 6C).

3.2. DipCo

DipCo also presented a BC membrane formation on the sample surface. Compared to DipShe, the membrane formation was much less consistent and showed unfulfilled regions with exposed net-like nanofibres and a rough, bulky surface (see Figure 7). Meanwhile, membranes were also found penetrating the fabrics in DipShe, while in DipCo, the cross-section revealed that membrane attachment predominantly occurs at the superficial fibres. The remoistening showed a crucial impact, tearing the smooth membrane parts and showing a web-like structure with agglomerations highlighted using arrows (see Figure 7). This structure was mostly found on the surface, with very little growth reaching into the fabric.

4. Discussion

As accumulation of waste and reliance on fossil resources continue unchecked, the development of biomaterials and sustainable processes is essential to promote efficient resource use and equitable economic opportunities. Nanocellulose has emerged as a material of growing interest [32], with BC derived from SCOBYs being particularly promising. This prominence is due to its high purity, allowing for simpler, less chemical- and water-intensive processing than conventional nanocellulose purification [12,33]. Additionally, BC production offers the opportunity to utilise waste streams as carbon and nutrient sources, further enhancing its sustainability [33,34,35]. Acknowledging that waste-based products face scalability limitations and thus local economics should be pursued, an expansion of SCOBY production should be explored to make BC an abundant and adaptable source of sustainable materials. Equally important is the development and industrial implementation of BC-based materials. More research into material diversity and actual industrial implementation is essential. Therefore, this work focused on the cultivation of composite materials with SCOBYs and the exploration of possibilities for product design, investigating whether and how SCOBYs can be cultivated in composite materials to open up new potential for high-quality products.

4.1. Biofilm Growth

The growth rate of the biofilm was low compared to instances in prior literature. Reported yields from similar studies ([12]: 33–90 g/L; [36]: 4.7 g/L/day) indicate that a two-week growth period should produce approximately 6.5 g. However, yields did not exceed 0.5 g in this study. While no culture showed an upward trend in yield, other studies, such as [37], have shown an increase in yield within the first 21 days, indicating an abnormal growth behaviour in this study. All samples were cultivated under identical conditions in the same containers, eliminating opportunities for comparative analysis. While the increased surface area in the setup should have prevented oxygen supply limitations, which can lead to a passive state [38], the closed lids may have restricted air exchange despite their design to promote circulation [39,40].
A starter culture with low metabolism was identified as a possible factor, as indicated by the randomly distributed differences in yield between DipShe and DipCo. While differences could have been expected between weeks 3 and 4 due to the shaking process, they appeared to occur at unrelated times instead [12]. The inoculum pH in this study (3.14–3.5) fell within the favourable range [11,12,16,36,41], and the extended fermentation time of six weeks further ruled out the influence of this factor. Low temperatures during fermentation (21 ± 2 °C during the day and ~5 °C lower at night) could have contributed to slowed growth, as optimal temperatures for BC production range from 24–28 °C [36]. However, temperature alone cannot explain the observed discrepancies. To better understand the parameters influencing yield and assess the setup’s suitability, experiments should be repeated under controlled conditions using a verified productive SCOBY strain.

4.2. SCOBY Growth in Scaffold Materials

In dip-in samples, SCOBY growth occurred within the reinforcement above the LAI, indicating vertical growth. Unlike conventional setups, SCOBYs did not form a uniform, dense film. Instead, membranes grew within the fibres of the scaffolds, extending up to 3 cm in DipShe and 5 cm in DipCo after the first week. This difference might be due to varying wicking capacities. This variation may result from the materials’ specific wicking abilities and capacities attributed to their fibre morphologies. Cotton fibres are hydrophilic [42]), while wool fibres have hydrophobic surfaces [43]. Differences in textile structures (felt vs. woven fabric) may also play a role and warrant further investigation through wicking tests. However, as the resulting membrane morphology differed from initial expectations and appeared more suitable for applications that work with membranes in the nanoscale, such as filtration or biomedical scaffolding, no further mechanical testing was conducted.
The BC membranes formed in DipShe and DipCo show different characteristics (compare Figure 5 and Figure 7). Membranes in DipShe are smooth and fully closed. There are fewer membranes after the rupture due to remoistening, but the morphology has not changed. In contrast, DipCo displays a non-closed, bulky membrane even before the dynamic moistening process. The different fibre orientations could have also led to different gaps, which might have influenced the difference in membrane structure between DipShe and DipCo potentially influencing the significant differences in yield distributions. Instead, it is unlikely that this is the reason for the nanonetting since gaps are of a different size and scale than the nanocellulose molecules produced.
The dynamic remoistening process initiated thin, web-like fibres enclosing cellulose spheres in DipCo, a phenomenon observed in agitated fermentation, which typically involves stirring or shaking [44]. However, in this study, the only agitation occurred during incubation at the beginning and after three weeks of growth. Any other agitation could be caused by a liquid stream due to gravity or capillary force, suggesting this must have happened a short time after the eruption until a force balance adapted. The reason for the formation of spheres in the cotton fabric alone remains unknown.
In DipShe, air pockets within the felt likely stimulated bacterial cellulose production around air bubbles, resulting in membranes distributed throughout the cross-section. In contrast, DipCo exhibited membranes attached only to the outermost fibres, suggesting a closed water surface limiting SCOBY growth to the outer LAI. The growth within the felt and the closed membrane in DipShe explains the higher yield than in DipCo. Although the same method was used, very different materials resulted from the two fabrics. SCOBY shows a high feasibility of growing in cotton with the ability to vary the membrane morphology.
This study reveals a new form of BC growth, which might be helpful for more technical applications such as biomedical or electrical materials, e.g., usable for filtration systems or energy storage. While waste streams might not suit these applications, alternative, pure, sterile scaffold materials such as porous ceramics or polymer fabrics should be considered.
Despite low yields due to a homegrown weak culture and limited trend data, this method demonstrated effectiveness within one week, highlighting its economic potential. The aim was to apply the “waste to value” principle. With the outcome showing microscale membranes instead of the typical strong biofilms built by SCOBYs, the application field and this kind of waste stream should be reconsidered. This approach produced membranes within the microscale, creating a high surface area. The membranes will be built wherever there is an LAI, meaning membranes will be formed even in three-dimensional scaffolds. The characteristics of the formed membrane depend on the scaffold and need further investigation.

4.3. Waste to Value—Design Perspectives

While much research [45,46,47] has been conducted on valorising agricultural waste into raw materials useful for product design, this study examines the possibility of ‘grown products’. This approach to fabricating products directly from growth mediums/inoculums utilising agents such as fungi, algae, and other microorganisms such as calcifying bacteria has received much academic interest lately [48,49]. These approaches eliminate the step of raw material extraction and standardisation in the conventional ‘bioresource–raw materials–product manufacture’ process and bridge the biomaterial-producing systems directly with the final product. This decentralised approach to product manufacturing could offer many advantages, such as lower energy consumption (using local resources and reducing transportation), product uniqueness and customizability (due to the biofabrication techniques employed), and support for waste valorisation in the communities. This strategy could significantly impact product manufacturing sectors such as footwear, apparel, interior lighting, and furniture.
Using a SCOBY as an agent for growing three-dimensional products is challenging, primarily because BC biofilm growth requires the liquid–air interface (LAI), necessitating an intermediary step—creating SCOBY sheets—for product manufacturing. Using scaffolds eliminates this issue and allows manufacturers to utilise various locally available scaffolding materials (such as plant- or animal-based fibres), often from biowaste. Besides scaffolding materials, the growth medium could also utilise many types of food and agricultural waste [50,51,52].

5. Conclusions

In today’s pressing global challenges, the urgency for innovation in efficient and sustainable resource utilisation has never been greater. Bacterial cellulose (BC) derived from SCOBYs presents a promising pathway to address these challenges in engineering sustainable material composites. This work explored a novel approach to producing BC composites, enhancing our understanding of the material’s potential for diverse applications. Future advancements in SCOBY-based materials will require interdisciplinary collaboration to address critical aspects, including societal needs, environmental impacts (evaluated through a Life Cycle Assessment (LCA)), and economic feasibility. Such a comprehensive approach is vital to effectively integrating these materials into sustainable systems.
Our results demonstrated the ability of a SCOBY to form membranes vertically within waste-derived sheep wool felt and cotton fabrics, showcasing the potential to repurpose textile waste. Instead of producing strong, dense composites suitable as textile substitutes, the process resulted in microscale membranes forming between the fibres, creating high surface area structures. These unique properties could find applications for packaging, energy storage, biomedical materials, controlled drug delivery/release, and filtration systems. While many aspects of growth conditions, scalability, and performance need to be optimised, our work contributes valuable insights into the diversity and potential of SCOBY-based biomaterials. These findings mark an essential step toward developing innovative, sustainable materials that align with the principles of a circular economy. We believe that this work provides the foundation for future research into grown SCOBY composites using vertical scaffolds. Figure 8 shows schematic examples of some potential scaffolds that can be explored in futures studies using this method. Future directions and application of such grown composites can include providing scaffolds for growing cells/microbes due to the abovementioned high porosity and interconnectivity of such composites that would provide space and aeration for growth and proliferation of cells. Other potential applications that need high surface area in the porous structures can be explored using this methodology. We hope that this work can provide inspiration and direction for future development of three-dimensional grown composites based on SCOBYs.

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/app15126396/s1, Table S1: The Dip-in samples were weight dry before and after the fermentation, which resulted in the grown SCOBY mass. The growth per used liquid volume defines the yield in g/L. The fibre-matrix ratio (f/m) is calculated using the dry weight of the fabrics as fibre and the growth of SCOBY as the matrix.

Author Contributions

Conceptualization, A.R.N. and M.T.; methodology, A.R.N., M.T. and J.K.; software, J.K.; validation, J.K. and M.T.; formal analysis, J.K.; investigation, J.K.; resources, A.R.N.; data curation, J.K.; writing—original draft preparation, J.K.; writing—review and editing, J.K., M.T., K.R. and A.R.N.; visualization, J.K.; supervision, A.R.N., M.T. and K.R.; project administration, A.R.N.; funding acquisition, A.R.N. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the New Zealand Ministry of Business, Innovation and Employment under the Āmiomio Aotearoa project hosted by The University of Waikato (UOWX2004).

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The original contributions presented in this study are included in the article. Further enquiries can be directed to the corresponding author.

Acknowledgments

The authors would like to thank the School of Product Design capable technical and administrative staff for their support during this research work.

Conflicts of Interest

The authors declare no conflicts of interest. The funders had no role in the design of the study, in the collection, analyses, or interpretation of data, in the writing of the manuscript, or in the decision to publish the results.

Abbreviations

The following abbreviations are used in this manuscript:
BCBacterial Cellulose
DipCoDip-in cotton fabric samples
DipSheDip-in Sheep wool felt samples
LAILiquid–air interface
SCOBYSymbiotic Culture of Bacteria and Yeast
SEMScanning electron microscope

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Figure 1. BC and SCOBY as a material have mainly been used to create design prototypes in fashion shows and exhibitions rather than in mass production. The primary application appears to be using them as substitutes for leather or textiles. (A): Jacket by Ganni used BC material CELIUM™ by POLYBION™ (https://www.polybion.bio/contact/) (accessed on 9 September 2024) [23]; (B): Shoe made out of SCOBY [24]; (C): Shoe made out of self-dyeing shape-grown BC [25]; (D): lampshade made from BC material [26]; (E): shoe out of BC reinforced with nonwoven fabrics [27]; (F): biodegradable, self-gluing packaging material [28].
Figure 1. BC and SCOBY as a material have mainly been used to create design prototypes in fashion shows and exhibitions rather than in mass production. The primary application appears to be using them as substitutes for leather or textiles. (A): Jacket by Ganni used BC material CELIUM™ by POLYBION™ (https://www.polybion.bio/contact/) (accessed on 9 September 2024) [23]; (B): Shoe made out of SCOBY [24]; (C): Shoe made out of self-dyeing shape-grown BC [25]; (D): lampshade made from BC material [26]; (E): shoe out of BC reinforced with nonwoven fabrics [27]; (F): biodegradable, self-gluing packaging material [28].
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Figure 2. (A): Schematic concept of experimental setup displaying SCOBY in orange and scaffold fibres in grey showing the growth after 2 days ((A), left), and the resulting growth after 1–6 weeks ((A), right). (B): Scaffolds ((left): sheep wool felt, (right): cotton fabric) showing the black string in the top which is used to fix the fabrics in hanging dipping-in position. (C): Infused scaffolds, fixed at the top, dipping in Kombucha tea ((left): sheep wool felt, (right): cotton fabric).
Figure 2. (A): Schematic concept of experimental setup displaying SCOBY in orange and scaffold fibres in grey showing the growth after 2 days ((A), left), and the resulting growth after 1–6 weeks ((A), right). (B): Scaffolds ((left): sheep wool felt, (right): cotton fabric) showing the black string in the top which is used to fix the fabrics in hanging dipping-in position. (C): Infused scaffolds, fixed at the top, dipping in Kombucha tea ((left): sheep wool felt, (right): cotton fabric).
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Figure 3. Analysis of SCOBY growth in dip-in samples using light microscopy. DipShe1 and DipCo1: Dried sample exemplars fermented for one week (with no differences observed from one to six weeks) showing the LAI. The sheep wool samples at the top had double the volume of liquid, raising the LAI. Microscopy images showing the growth observed (in cm) over the LAI according to the scale on the right. Membrane growth is shown in colour (yellow), while shaded areas mark a lack of BC membrane. In the sheep wool samples, no growth is observed higher than 3 cm over the LAI, while in cotton samples (bottom), growth is observed at 5 cm over the LAI.
Figure 3. Analysis of SCOBY growth in dip-in samples using light microscopy. DipShe1 and DipCo1: Dried sample exemplars fermented for one week (with no differences observed from one to six weeks) showing the LAI. The sheep wool samples at the top had double the volume of liquid, raising the LAI. Microscopy images showing the growth observed (in cm) over the LAI according to the scale on the right. Membrane growth is shown in colour (yellow), while shaded areas mark a lack of BC membrane. In the sheep wool samples, no growth is observed higher than 3 cm over the LAI, while in cotton samples (bottom), growth is observed at 5 cm over the LAI.
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Figure 4. Boxplots showing the yield in g/L per week. Yield was assumed to be the mass change in the scaffold in the dried state before and after the fermentation related to the volume of inoculum provided. DipShe: right; DipCo: left.
Figure 4. Boxplots showing the yield in g/L per week. Yield was assumed to be the mass change in the scaffold in the dried state before and after the fermentation related to the volume of inoculum provided. DipShe: right; DipCo: left.
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Figure 5. SEM images of DipShe samples from two and four weeks of fermentation compared in their surface (the outside of the fabric stripe) and cross-section (cut through the fabric stripe, facing orthogonally) morphology. These durations were chosen to display and understand the impact of remoistening the scaffolds, which altered the biofilm morphology.
Figure 5. SEM images of DipShe samples from two and four weeks of fermentation compared in their surface (the outside of the fabric stripe) and cross-section (cut through the fabric stripe, facing orthogonally) morphology. These durations were chosen to display and understand the impact of remoistening the scaffolds, which altered the biofilm morphology.
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Figure 6. SEM showing the detailed interactions between the wool fibres and the grown nanocellulose membrane in DipShe samples. (A): Membrane attached to fibres forming a film between the wool fibres, (B): nanocellulose membrane wrapping around wool fibres, and (C): grown nanocellulose membrane covering sheep wool fibres.
Figure 6. SEM showing the detailed interactions between the wool fibres and the grown nanocellulose membrane in DipShe samples. (A): Membrane attached to fibres forming a film between the wool fibres, (B): nanocellulose membrane wrapping around wool fibres, and (C): grown nanocellulose membrane covering sheep wool fibres.
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Figure 7. SEM images of DipCo samples from two and four weeks of fermentation compared in their surface and cross-section morphology. Comparing the membrane before and after remoistening reveals changes in biofilm formation. Yellow arrows highlight the agglomerates on the web-like structures.
Figure 7. SEM images of DipCo samples from two and four weeks of fermentation compared in their surface and cross-section morphology. Comparing the membrane before and after remoistening reveals changes in biofilm formation. Yellow arrows highlight the agglomerates on the web-like structures.
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Figure 8. A Schematic representation of some of potential future direction of vertically grown SCOBY composites, (A): using waste bone as scaffold; (B): using stiff specifically designed ceramic or metal scaffolds; (C): ingrown SCOBY in fibrous scaffolds using diverse shapes of the scaffold, e.g., the half sphere on the right. The orange colour represents the SCOBY membrane.
Figure 8. A Schematic representation of some of potential future direction of vertically grown SCOBY composites, (A): using waste bone as scaffold; (B): using stiff specifically designed ceramic or metal scaffolds; (C): ingrown SCOBY in fibrous scaffolds using diverse shapes of the scaffold, e.g., the half sphere on the right. The orange colour represents the SCOBY membrane.
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Kniep, J.; Thundathil, M.; Rezwan, K.; Nazmi, A.R. Biofabricating Three-Dimensional Bacterial Cellulose Composites Using Waste-Derived Scaffolds. Appl. Sci. 2025, 15, 6396. https://doi.org/10.3390/app15126396

AMA Style

Kniep J, Thundathil M, Rezwan K, Nazmi AR. Biofabricating Three-Dimensional Bacterial Cellulose Composites Using Waste-Derived Scaffolds. Applied Sciences. 2025; 15(12):6396. https://doi.org/10.3390/app15126396

Chicago/Turabian Style

Kniep, Jula, Manu Thundathil, Kurosch Rezwan, and Ali Reza Nazmi. 2025. "Biofabricating Three-Dimensional Bacterial Cellulose Composites Using Waste-Derived Scaffolds" Applied Sciences 15, no. 12: 6396. https://doi.org/10.3390/app15126396

APA Style

Kniep, J., Thundathil, M., Rezwan, K., & Nazmi, A. R. (2025). Biofabricating Three-Dimensional Bacterial Cellulose Composites Using Waste-Derived Scaffolds. Applied Sciences, 15(12), 6396. https://doi.org/10.3390/app15126396

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