Use of bacterial cellulose in the textile industry and the wettability challenge - a review


 Bacterial cellulose (BC) has been studied as an alternative material in several segments of the food, pharmaceutical, materials and textile industries. The importance of BC is linked to sustainability goals, since it is an easily degradable biomaterial of low toxicity to the environment and is a renewable raw material. For use in the textile area, bacterial cellulose has attracted great interest from researchers, but it presents some challenges, notably hydrophilicity due to its porous structure. This bibliometric review article gathers studies and methods related to minimizing the hydrophilicity of bacterial cellulose in order to expand its applicability in the textile industry. The databases consulted were ScienceDirect, ProQuest and Web of Science, the documents investigated were scientific articles and the time period investigated was between 2015 and 2021. The discussion is focused on the applicability of BC in the textile industry, highlighting the research needs, especially with regard to reducing wettability.


Introduction
The textile industry is associated with numerous environmental problems. Large amounts of harmful waste are generated at all stages of clothing manufacturing, with negative environmental and social impacts, such as land ll consumption, low resource e ciency and air/soil pollution (Chan et al. 2018;Correia and Silva 2019;Sandvik and Stubbs 2017). Although the garments are used for a relatively long period, even by several consecutive users, studies have demonstrated that the manufacture of cotton garments, for example, is extremely polluting.
To obtain 1 kg of cotton ber, 29 tons of water are consumed. In total, 25% of all insecticides and more than 11% of pesticides used globally in agriculture are applied to cotton crops. The amount of material that requires disposal presents a real challenge for the fashion industry. This quantity has increased notably in the past 50 years, with around 15 million tons of used textile waste currently being generated each year in the USA (Domskiene et al. 2019).
The quest to make the fashion industry more sustainable has increasingly directed designers and scientists to focus on biomaterials, such as bacterial cellulose (BC), and their biocompatible properties.
BC is environmentally friendly, safe for the human body and considered a renewable raw material, and one way to obtain it is through the kombucha fermentation process (Domskiene et al. 2019). It is a natural, non-woven material, rmly structured, with an appearance that resembles leather (Chan et al. 2018;Domskiene et al. 2019;Sederavičiūtė et al. 2019).
Biomaterials are mixtures of natural substances that offer biocompatibility and they can improve the quality of life of individuals and increase longevity and comfort (Costa et al. 2019). Domskiene et al. (2019) noted that the use of biomaterials in the fashion trade is very promising, since the material can be grown as required from waste food and used clothing can be easily decomposed and biodegraded (Domskiene et al. 2019). Cellulose is one of the most abundant polymers on Earth and most of it is plant cellulose (PC), however, bacterial cellulose (BC) offers an interesting alternative (Costa et al. (2020), in a recent review, address cellulose in the food industry, while Volova et al. (2019) suggested BCbased biotechnological dressings for the health sector (Lin et al. 2020;Volova et al. 2019).
Furthermore, Costa et al. (2019) stated that BC is able to play a role as a substitute for other materials in the textile area and Araújo et al. (2015) developed a hydrophobic BC material which may have interesting applications for use in textile materials, clothes, ooring and other interior design materials (Araújo et al. 2015;Costa et al. 2019).
One of the ways to produce BC is in the production of kombucha, a probiotic drink which, according to the earliest records, originated in northeastern China in mid-220 AD. It appeared during the Chin dynasty, when a Korean doctor called '' Kombu '' used the "che" for treatments, thus originating the name Kombuchá (Amarasekara et al. 2020). After the Second World War, the use of Kombucha became popular in Western countries due to its multiple functional properties, and the drink subsequently spread worldwide (Dima et al. 2017;Dutta and Paul 2019;Pei et al. 2020).
Fermentation is considered to be one of the oldest methods for obtaining drinks and involves a low cost energy conservation system (Dutta and Paul 2019). BC fermentation is carried out during the tea fermentation process, generating a cellulose-based bio lm at the air-liquid interface. This is generated by the symbiotic culture of bacteria and yeasts (SCOBY) and is considered as a waste product, but it represents an important potential source of BC (Dutta and Paul 2019;Kamiński et al. 2020;Leal et al. 2018;Villarreal-Soto et al. 2018).
In the case of the textile industry, materials for the production of clothing must provide a required set of properties, such as strength, body t and comfort. Scientists working in the textile eld have recently become interested in BC, but this material presents challenges to be overcome before it can be widely applied as a new type of textile fabric for the fashion industry (Domskiene et al. 2019). Despite offering excellent hydrophilicity for some sectors, such as biomedicine and cosmetology, due to its porous structure, this characteristic poses a problem for some uses in the textile industry (Domskiene et al. 2019;Halib et al. 2019;Kamiński et al. 2020).
In this context, the aim of this paper is to provide a bibliometric review of the academic literature focused on the hydrophilic property of BC and the treatments available to make it hydrophobic. Some potential applications of BC in the textile sector and the importance of future research on biomaterial, especially with regard to wettability, are discussed.

Methods
The procedure involved a bibliographic review of an analytical nature. Bibliometric analysis was carried out, mapping information from bibliographic records of documents stored in databases. The databases consulted were ScienceDirect, Proquest and Web of Science.
These databases were selected due to the large number of documents in their collections: a) ScienceDirect is considered Elsevier's most important peer-reviewed academic literature platform and has more than 3,800 journals and more than 39,000 book titles; b) Proquest: is comprised of 40 databases that provide a single source for academic journals, newspapers, reports, working papers and datasets; and c) Web of Science: makes tools available for analyzing citations, references and the h-index, to aid bibliometric analysis. It covers approximately 12,000 journals. Figure 1 shows a ow diagram of the method used for the identi cation of articles to be included in this review.
As seen to Figure 1, the terms used to search for documents were "bacterial cellulose" AND hydrophobic AND textile. It should be noted that the articles to be considered in this review were selected considering the years 2015 to 2021, giving preference exclusively to academic articles and disregarding other categories of documents. The inclusion and exclusion criteria were applied by reading the title, abstract and keywords. Thus, only articles that were compatible with the research proposal were selected, that is, those related to methodologies that could be used to improve the hydrophobicity of BC.

Analysis of databases
For each database, the search terms "bacterial cellulose" AND hydrophobic AND textiles were used. In the ScienceDirect database the results obtained were 615 documents with search terms and applying the lters document type (articles) and the time cut offs (2015-2021) resulted in 259 articles. In the Proquest database the results obtained were 379 documents with the search terms and applying the same lters resulted in 262 articles.
In the Web of Science database the results obtained were 11 documents with the search terms and applying the lters mentioned above resulted in 9 articles. Thus, a total of 531 articles were identi ed for further analysis. Figure 2 shows these results in graphic form.
As shown in Figure 2, a higher number of documents was identi ed in the ScienceDirect database, followed by ProQuest, using only the search terms. However, with the use of the "document type" and "time clipping" lters, there was a signi cant decrease compared to the ScienceDirect database. The Web of Science database provided the lowest number of relevant articles.

Final selection and analysis of articles
The nal selection of the articles considered for the writing of this review was carried out in two stages. Stage 1 involved the reading of the title, abstract and keywords of each article. Those that were aligned with the search theme, that is, the articles that mentioned bacterial cellulose, its hydrophobicity and its use in textiles were selected. In step 2, the articles were read in full and based on the content only those that would aid the construction of the bibliometric review were selected.
In this process, the numbers of articles excluded were 231 from the ScienceDirect database, leaving 28 articles, 252 from the ProQuest database, leaving 10 articles and 4 from the Web of Science, leaving 5. Also, two articles were duplicated, one found in both the ProQuest and ScienceDirect databases and another in the ProQuest and Web of Science databases. Thus, 41 articles were considered for the review and details of this nal selection process can be seen in Figure 3.
From the bibliometric process applied in this research, as shown in Figure 3, it was possible to select a set of articles that contributed to gaining a better understanding of a natural property of BC, that is, its hydrophilicity. In addition, the main focus of the articles was identi ed as methods to obtain more hydrophobic bacterial cellulose. It should be noted that after the exclusion of articles that were not compatible with the theme, the Science Direct database remained the largest source of articles used to carry out this review.

Classi cation of articles
The 41 articles analyzed for the writing of this document were classi ed according to the year of publication, the journal of publication, the country where the article was produced and the number of times the article had been cited. The purpose of this analysis was to observe the frequency and abundance of publications related to studies on the wettability of bacterial cellulose. In Supplementary Information you can access the table with the list of articles used and details.
Most of the articles were published between 2019 and 2020. Although BC has been a research topic for some time, studies on changes in its structure, such as hydrophobicity, are more recent. It was noted that in terms of the journals of publication, most of them deal with the areas of polymer science, applied and organic chemistry, biochemistry and molecular biology. Finally, the most common countries of origin of the published articles, in decreasing order, were China, Portugal, USA and Spain.
Figure 4 details the terms with the highest occurrence in the articles selected to carry out the bibliometric review.
It was clearly observed that the research focus was bacterial cellulose, this being the theme with the highest number of occurrences in the articles. Regarding the time period considered (2015 and 2021), the expressions hydrophilicity and superhydrophobicity appear in greater quantity after 2018. Subsequently, the studies on the use of bacterial cellulose to produce textiles gained strength, offering an alternative to leather and a move toward greater sustainability. Therefore, as noted by some authors (see below), more research is needed on the hydrophobicity of bacterial cellulose for use in the textile industry, as this is an extremely important property of textile materials, particularly in the case of a potential substitute for leather.

The hydrophilicity properties of bacterial cellulose
Bacterial cellulose (BC), in addition to its mechanical resistance, has several attractive physical properties. It has higher purity compared to cellulose of plant origin, along with greater exibility, greater hydrophilicity, tensile strength, biodegradability and transparency ( Untreated BC has greater hydrophilicity, indicating its naturally high wettability (Dima et al. 2017;. Although this is an interesting property for some sectors, without hydrophobic treatment, it limits the use of this material. According to Sederavičiūtė et al. (2019) and Martins et al. (2020), due to the hydrophilic nature of BC, the search for stability of the material dimensions is relevant, because during drying the sample can shrink (Martins et al. 2020;Sederavičiūtė et al. 2019).
According to Bagewadi et al. (2020), Paximada et al. (2020) and Sederavičiūtė et al. (2019), BC material has a high moisture content, since water binds to the OH groups of the material, making it hydrophilic (Bagewadi et al. 2020;Paximada et al. 2020;Sederavičiūtė et al. 2019). The moisture content results from the microstructure of the BC material and affects both the physical and mechanical properties, such as density, thickness, tensile strength and plasticity. Studies have shown an increase from 91% to 98% in the water content and from 87% to 97% for NaOH after 8 h of washing (Sederavičiūtė et al. 2019).
In studies reported by Bagewadi et al. (2020) and Halib et al. (2019), BC molecules lead to a highly swollen three-dimensional (3D) network and pore structures that are capable of holding a maximum of 99% water, resulting in BC as a promising material for obtaining highly biocompatible tissue structures (Bagewadi et al. 2020;Halib et al. 2019). Research has shown that BC (not optimized), BC (optimized) and BC gelatin hydrogel composites have very distinct water retention capacity (Bagewadi et al. 2020). The properties of BC can be altered by different chemical changes which can be used to improve the properties according to different applications (Halib et al. 2019).
Studies have also shown that the material properties need to be altered prior to biosynthesis (in situ), which changes the intrinsic biophysical properties, in the case of cellulose bers through the incorporation of bioactive molecules, modifying the porosity and/or crystallinity of BC (Fernandes et al. 2020). Also, the application of chemical nishing can reduce the hydrophilicity of the BC lm surface, potentially allowing its application under different conditions (Domskiene et al. 2019).
In addition, the BC water retention capacity can be varied by using different combinations of culture media, which can alter its structure and thus modify its properties (Bagewadi et al. 2020). In this way, properties similar to those of clothing bers can be produced, depending on the parameters of the fermentation process, the application of which is growing in the fashion industry (Domskiene et al. 2019).
Due to its good biocompatibility, during immersion in a solution BC can interact with exogenous molecules, such as nanocomposites, enzymes and proteins (Fernandes et al. 2020). Although BC lm has properties which attract great interest, studies show that it can undergo deformation and it is di cult to guarantee a uniform structure, thickness and porosity, and therefore the material is not durable (Domskiene et al. 2019).
For the production of textile fabrics, the thickness and uniformity of the material are priorities of great importance in the drying process, but the BC dimensions change and it becomes highly hydrophilic during the drying step (Domskiene et al. 2019). The application of tobacco residue extracts (without nicotine) in the BC culture medium has been used a fermentation strategy to optimize the substrate, obtaining a 1.6fold higher yield. When adding 1% of rapeseed oil to the culture medium, a 600% greater yield was obtained. Also, the improvements in the material resulted in a signi cant increase in the water absorption capacity and mechanical strength of the BC material (Fernandes et al. 2020).
Despite the extremely hydrophilic characteristic of BC, Wood (2019) noted that this property is not suitable for use under conditions of high humidity, which can increase with proximity to human skin. Therefore, bacterial cellulose cannot be used for domestic cleaning, for example, but research in this eld continues to explore this aspect (Wood 2019).
However, recent research on hydrophilicity found that when this feature of BC is desirable, there is potential for increasing this property. Jiang et al. (2020) and Sulaeva et al. (2020) reported the biological modi cation of bacterial cellulose (BC) using various alginates with different molecular weights as a carbon source in the fermentation medium. According to Jiang et al. (2020), the presence of sodium alginate (SA) had a strong in uence on the microstructure of the components resulting from bacterial cellulose incorporated with sodium alginate (SA-BCs) and results indicated that the hydrophilicity of SA-BC was strengthened and suggested the presence of a carboxyl group (Jiang et al. 2020). Sulaeva et al. (2020) found that the addition of hydrophilic alginate as a secondary component to BC-based dressings represents an elegant method of improving their moisture retention properties.
Finally, Li et al. (2020) manufactured polymer-modi ed carbonization bacterial cellulose (CBC) electrodes using varying amounts of cation exchange polymers (glutaric acid (GA) and sulfosuccinic acid (SSA)). The polymer-modi ed CBC electrodes showed good wettability, due to the addition of oxygen-containing groups that increase the hydrophilicity of the CBC. The high content of the hydrophilic group contributes to the excellent electrosorption performance of the electrodes prepared ).

Studies and alternatives for a hydrophobic bacterial cellulose
It is known that there are different possibilities for the use of BC, therefore, new alternatives for its use in association with natural products have been researched, seeking to maintain its safety and quality and also to extend its useful life . Bacterial cellulose (BC) can be produced in large quantities through a microbial fermentation process, providing a renewable, inexpensive, biodegradable and nontoxic biomaterial ).
However, BC-based superhydrophobic membranes are more rarely reported, possibly due to the restricted network of cellulose nano brils, which can impair performance by limiting liquid in ltration . Most of the methods reported in the literature for the manufacture of superhydrophobic membranes involve phase separation, electrospinning, immersion coating and electrochemical approaches ). Thus, the search for methods to improve the hydrophobicity of bacterial cellulose is an important research topic, and the main procedures investigated are detailed in Figure 5.
The use of exogenous molecules in BC production, through the in situ method, leads to different results for the BC properties. In situ modi cation is less commonly applied, since the application of hydrophobic matrices can result in weak interfacial bonds with cellulose (hydrophilic) and chemical compatibility is therefore a prerequisite (Fernandes et al. 2020). In addition, application is suitable only for cases of polymerization in liquid solutions, where cellulose can be distributed in the polymerization medium (Fernandes et al. 2020).
Xiang and Acevedo (2017) performed studies to investigate the use of PLA bers. To improve the mechanical and hydrophobic properties of bacterial cellulose (BC), self-assembled BC nanocomposites were prepared in situ using electrophilic hydrophobic acid (PLA) or PLA/lipids (PLA/Lip) as a basis for the growth of BC nano bers (Xiang and Acevedo 2017). It was observed that using electroplated PLA mats for the BC culture medium led to a two-fold increase in the resistance of the material, with a 52% increase in the elongation of nanocomposites in relation to BC. The incorporation of electrospun PLA and PLA/Lip nano ber mats decreased the moisture recovery and water vapor transmission of BC nanocomposites compared to pure BC (Xiang and Acevedo 2017).
A recent study highlights the ability of BC 3D microtopography to be precisely controlled and customized using modern engineering, and this can be used to manipulate BC formation at the air-water interface through the use of hydrophobic particles and superhydrophobized surfaces (Halib et al. 2019). Thus, hydrophobic polytetra uoroethylene (PTFE) particles were used to carry out the 3D biofabrication process, where access to oxygen around liquid marbles was promoted, as well as injection molding or printing in 3D using PTFE particles (Halib et al. 2019). The authors postulate that the high air permeability, obtained through a continuous air network generated by hydrophobic microparticles, allows high delity in the replication of the molds, since it generates robust bio lms.
Another alternative for the use of hydrophobic BC was identi ed in a study by Hou et al. (2019). A simple modi cation method suitable for many other porous materials was carried out to control wetting behaviors by adjusting the hydrophobic and hydrophilic compositions of alkoxysilanes. BC-SiO 2 membranes were rstly modi ed with CDMOS and then BC superhydrophobic membranes (SHBC) were obtained (Hou et al. 2019). In addition, it was found in this study that it is possible to adjust the wettability of the nal membranes easily by changing the composition of alkoxysilanes in the hydrolysis process. He et al. (2018) studied the preparation of bacterial cellulose aerogels/silica aerogels (BCAs/SAs), using BC as a three-dimensional self-assembled skeleton for reinforcement and silica aerogels derived from methyltriethoxysilane as the lling, through vacuum in ltration and freeze drying. The results showed superhydrophobicity with a contact angle of 152° and superoleophilicity resulting from methyl groups on the surface of the silica aerogel ller (He et al. 2018).
Lin et al. (2020) prepared lms with a bulky structure of BC and the surface properties showed increased hydrophobicity. They also studied biodegradable multi-layered lms based on BC with the addition of sorbic acid (SA) as an antibacterial agent. The modi ed lms showed water vapor barrier properties, at different levels of relative humidity. The antibacterial activity of the BC lms with SA incorporated was altered by the concentration of both BC and SA (Lin et al. 2020).
It should be noted that the hydrophilic nature of hydroxyl groups causes low dispersion in nonpolar solvents and polymer matrices. Therefore, hydrophobization is often used to improve compatibility (Abitbol et al. 2016). In addition to the commonly used alkyl groups, these authors found that various hydrophobic groups with different functional groups (e.g., uorine, alkenyl, alkynyl, thiol groups and pyridine moieties) can be inserted in the process. They also noted that the exibility of these materials lies in the nature and chemistry of the cellulose surface, and with little effort the nanocellulose can become compatible with and adapted to hydrophilic and hydrophobic components.
According to Song et al. (2020), to overcome the disadvantages of hydrophilicity, previous studies on modifying the structure of BC chemically have been carried out, using various functional materials, such as polyethylene glycol, silver nanoparticles and zinc oxide. It was observed that these materials could be incorporated into three-dimensional BC matrices and provided greater crystallinity, porosity, hydrophobicity and mechanical properties (Song et al. 2020).
The same authors applied methods using lauryl gallate, the n-dococyl ester of gallic acid, a functional polymer useful for the modi cation of lignocellulose ber, such as hardwood kraft cellulose, to nonwoven BC. The conditions of controlled oligomerization were 160 U/ml laccase and 20 mM lauryl gallate. After the bacterial cellulose had been treated through the physical entrapment of lauryl gallate oligomers, an angle of contact with water of 88º was observed and the durability of the BC was con rmed by tensile strength measurements (Song et al. 2020).  described a process of exhaustion through the use of commercial hydrophobic polymers, a softener and a hydrophobizer based on uorocarbon, to make the BC ber more hydrophobic. In a similar process Araújo et al. (2015) used two different procedures. The rst starts with the softener bath followed by the hydrophobic nish bath and the other starts with the hydrophobic nish bath and ends with the use of the softener bath (Araújo et al. 2015). Both methods improved the hydrophobicity of bacterial cellulose, but no studies on the disposal of these synthetics after use and the effect on the environment have been reported .
In research by Lv et al. (2016), bacterial cellulose was consecutively functionalized by magnetron sputtering and reaction with copper (Cu) and Al 2 O 3 to provide it with unique electromagnetic antioxidation shielding properties, while improving the hydrophobic, mechanical and thermal properties. The surface topography and chemical properties of BC/Cu/Al 2 O 3 nanocomposites were examined by different techniques to verify that the metal-based nanoparticles were uniformly deposited on the surfaces. This sandwich structure of the nanocomposites increased their thermal stability, hydrophobicity, mechanical properties and electromagnetic interference (EMI) shielding effectiveness (Lv et al. 2016).
Researchers have also demonstrated a new method for processing bacterial cellulose/graphene oxide (BC/GO) aerogels with multifunctional properties. They described a simple way to improve the dimensional and mechanical stability of light and hydrophilic GO-based materials, especially in humid environments. This consisted of reducing the GO, removing functional groups containing oxygen, and consequently decreasing the original hydrophilicity of the material (Pinto et al. 2020).
The morphology and dimensional stability of 3D bacterial cellulose/graphene oxide (BC/GO) aerogels can be tailored to speci c needs, exploring different reduction strategies for enhanced interfacial hydrophobic-hydrophilic interactions between individual nanoelements (Pinto et al. 2020).  found that after the carbonization process, the BC/graphene spheres showed excellent capacity to absorb oils and organic solvents due to their highly porous surface, 3D interconnected structure and high mechanical stability, giving good hydrophobicity and elasticity results ). Polyaniline was produced through the green in situ polymerization of aniline by the Myceliophthora thermophila laccase at pH = 4.25 ° C, in the presence of a mediator, 1-hydroxybenzotriazole (HBT), using two different reactors, a water bath (WB) and an ultrasonic bath (US). They observed that the samples acquired hydrophobicity and showed conductive electrical behavior and a strong coloring, opening new routes for the exploration of functionalized bacterial cellulose as a green material for technical textiles, wearables and other applications (Shim et al. 2019).
Tests have also been carried out with triazine and hypocrelin.  prepared BC membranes with modi cations using triazine (TCT-BC) and grafting with hypocrelin (Hc-BC). The TCT-BC samples had a more compact surface, with smaller pores randomly distributed within the brous structure. It was thus assumed that a combination of intra/inter-bril crosslinking by TCT produces a more hydrophobic surface (contact angle h = 66.7). However, with the immobilization of hypocrelin on the BC surface, even smaller pores were produced, increasing the surface hydrophobicity (h = 75.5) . The modi ed membranes were compared with pure BC membranes.
A study by Santos et al. (2015) was aimed at the puri cation of BC but some hydrophobic properties were observed. The research consisted of the cultivation of BC and puri cation by two different methods: an alkaline treatment where the culture medium contained ethanol and a thermal treatment using a medium without ethanol. On comparing the untreated layers, the authors observed that the angles were greater when the BC was treated with ethanol (E-BC) compared with the layers without ethanol (nE-BC). This may be because the ethanol contributed to generating a cellulose layer with a certain degree of super cial hydrophobicity. Therefore, this topic merits further research (Santos et al. 2015).

Bacterial Cellulose Applications For The Textile Industry
The textile industry, despite being an important global manufacturing sector, is directly related to negative environmental impacts resulting from the use of toxic chemicals, the consumption of huge amounts of energy and water and inadequate disposal (Luo et al. 2020;Singh et al. 2019). Therefore, to achieve a more sustainable consumption scenario, it is necessary to nd solutions to reduce the negative environmental, social and economic impacts of this industry (Freudenreich and Schaltegger 2019;Ingulfsvann 2020).
One solution would be to invest in areas such as biotechnology that explore alternatives, such as the use of microorganisms, for the manufacture of textiles, both for clothing and in the footwear industry (Camere and Karana 2018;Saraç et al. 2019). Therefore, several tests have been carried out on bacterial cellulose (BC), to explore its exclusive properties, such as high purity, absence of lignin and hemicellulose, high crystallinity, high polymerization, good exibility, tensile strength and nano bril network structure (Chan et al. 2018;Kurniawan et al. 2012;. BC resources grown from bacteria have been developed mainly as ne materials to replace animal leather and BC has been increasingly used in tissue engineering structures (Camere and Karana 2018;Chan et al. 2018;).
The application of bacterial cellulose in the fashion industry has been the focus of many studies. Chan et al. (2018) developed an innovative technique for the production of bacterial cellulose textiles called "bespoke cultivation", taking advantage of the fact that bacterial cellulose can be cultivated and grown in any format. This type of cultivation is suitable for producing basic fashion items, such as simple shirts, tshirts and trousers, as these items do not require complicated shapes and their timeless styles are not restricted to trends (Chan et al. 2018). Ng and Wang (2015) performed tests related to the comfort and appearance of tissues obtained from bacterial cellulose. A total of 150 individuals participated in the test and the factors considered were comfort associated with touch, comfort associated with exibility and comfort related to breathability.
The result regarding the patterns analyzed was positive and it was possible to produce some prototypes of pieces of continuous 3D fashion (Ng and Wang 2015).
According to Chan et al. (2018), the use of bacterial cellulose in the textile industry adheres to the concept of low to zero waste, but these materials are limited to patterns for speci c types of clothing and are di cult to apply to the conventional manufacture of items of daily use. Zero waste patterns require a longer design process and more technical support for the execution of designs due to the special pattern allocation. Because it is not cost effective and is time consuming, zero waste design has not been widely used in the fashion industry (Chan et al. 2018).
Another relevant factor for the textile industry is the biodegradable nature of BC (Cazón et al. 2020;García and Prieto 2019) which could be successfully applied to obtain ecologically-friendly products (Cazón et al. 2020;Freudenreich and Schaltegger 2019). It should also be noted that for the manufacture of bacterial cellulose, only small amounts of water and energy are needed (Fernandes et al. 2020;Yim et al. 2017). Therefore, it can be considered an eco-friendly biomaterial and a mitigator of negative impacts within the textile chain.
Despite the various bene ts of using bacterial cellulose, there are still many technical and practical problems associated with the manufacture of clothing that need to be resolved, such as mechanical durability, comfort, material contamination, organic acids (responsible for the characteristic unpleasant smell), and attack by microorganisms (Kamiński et al. 2020). This review addresses one such property of BC, its wettability, as can be seen in Figure 6.
It was observed that despite its natural characteristic of being hydrophilic, which is advantageous for many applications, for instance, in the area of health, a more hydrophobic biomaterial would be of great interest for the textile industry. According to Araújo et al. (2015) and , the hydrophilic nature of BC prevents the combination with hydrophobic polymeric matrices, presenting a challenge for the development of textiles (Araújo et al. 2015;. In the textile industry, a hydrophobic cellulose material would have a wide range of applications, for instance, for clothing and impervious stain-resistant textiles, among others. Cellulose fabrics with hydrophobic ber surfaces are suitable for producing water repellent items, as they resist water but have some porosity, which allows the transport of moisture for user comfort. Studies to reduce the hydrophilicity of the modi ed cellulose surface have involved different technologies with broken effects and diameters (Araújo et al. 2015).
Although bacterial cellulose is biodegradable, renewable and biocompatible, its inherent properties, such as low strength, stiffness, high fragility and a hydrophilic nature, make it a poor biomaterial for application in commercial products (Dhar et al. 2019). However, currently, one of the main ecological problems, with regard to the textile industry and the use of clothing, is the issue of the disposal of textile waste. Since most of this waste is not biodegradable, being synthetic and derived from oil, further studies on bacterial cellulose would be of great interest (Kamiński et al. 2020) Research seeking to improve or modify the BC properties, to address, for example, the issue of hydrophobicity, could lead to more alternative biodegradable materials being inserted in the textile market. This issue merits increased investment, as the textile sector needs to identify new sustainable materials and, therefore, offering hydrophobicity must be aligned with proposal to increase sustainability in this sector. It should be noted, however, that other relevant properties, such as durability and biodegradability, must remain unchanged (Kamiński et al. 2020).
Thus, it is clear that further studies on the applicability of BC in the textile area are needed so that this biomaterial can be applied effectively and on a large commercial scale. Finally, according to Camere and Karana (2018), engineering seeks solutions that can be expanded, rather than to produce unique artistic pieces. Interdisciplinary collaborations are indispensable in confronting the complex challenge of sustainability, and experimentation through individualistic practices, as is the case of artisanal production, will not be effective. The results of this approach can often be applied to consumer products in the near future (Camere and Karana 2018).

Trends, Future Perspectives And Conclusions
Studies on bacterial cellulose, obtained through the kombucha fermentation process, as a sustainable alternative for use as a fabric have been promising. Reduced water consumption, decreased use of insecticides and pesticides, and reduced waste, are among the advantages of using this biomaterial in the textile industry.
Several properties of bacterial cellulose, such as mechanical strength, high crystallinity and threedimensional structure, favor the use of this material in the textile industry, but its hydrophilicity poses a challenge for its application as a textile ber. Based on the studies considered in this review, hydrophobic chemicals could be used (if other desirable properties of BC are maintained) to reduce the water absorption capacity, providing positive results. However, the material obtained would not be suitable for some applications, such as domestic cleaning.
The continuation of studies and tests is indispensable, so that biodegradable materials can be inserted in the textile market. Major issues to be addressed are obtaining materials with hydrophobicity and nding suitable means to dispose of the chemicals used to improve the ber of biodegradable materials aimed at the textile market.

Declarations
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Con icts of interest/Competing interests
The authors claim that there are no con icts of interest.
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