**2. Source of cellulose in nature**

*Nanofibers - Synthesis, Properties and Applications*

delignification, and spinning stages [2].

the speed of demand for clothing in the world.

various substrates which cause lower production costs [3].

because they are easily degraded by the environment [4].

this method is known to require a production time of around 4–5 months. Cellulose fibers have several advantages, including the resulting cellulose fibers can have unique properties depending on the type of tree used as the source of cellulose, have high mechanical strength and high flexibility. However, cellulose fibers produced from tree cellulose also have drawbacks, namely requiring long stages and a long time in the production process. Several stages that must be passed when carrying out the cellulose fiber production process, including the kraft cooking, bleaching,

Based on the prediction data of FAO (2016), the demand for cellulosic fiber production will increase by around 1.5% per year, to reach the demand of 28.3 million tonnes in 2025. This prediction is inversely proportional to the prediction that the stock of cellulosic fiber production in the world will decline. This data is predicted to occur due to an imbalance between the speed of cellulosic fiber production and

Currently, researchers are developing alternative production methods to meet the deficit in cellulose production. One of the alternative methods being developed is the production of cellulose from bacteria. This method is considered to be able to help the deficit in cellulose production, due to the production process which requires a relatively shorter time. Production of cellulose from bacteria is known to be carried out by groups of acetic acid bacteria, such as *Acetobacter xylinum* or *Gluconobacter sp*. The production of cellulose fibers from bacterial cellulose also has several advantages such as the purity of cellulose in bacterial cellulose which is higher ~90%, does not contain lignin and hemicellulose and can be produced in

Symbiotic Culture of Bacteria and Yeast (SCOBY) Kombucha is a cellulose product from bacteria that is considered a potential substitute for cotton for fabric raw materials. SCOBY is known to be a byproduct in the kombucha industry, which is currently experiencing limited application development. Currently, several world designers have succeeded in making works using fabrics based on SCOBY. The resulting fabric has a flexible texture and is brown like synthetic leather. Fabrics based on SCOBY are also considered cheap and more environmentally friendly

Until now, the use of SCOBY as a fabric base still has problems, where the fabric produced from SCOBY kombucha, directly through the drying process, has the characteristic of being very easy to absorb water. This characteristic is a drawback for SCOBY based fabrics, because the water bound in SCOBY based fabrics is difficult to dry and can make SCOBY return to its original shape. Another problem with the use of SCOBY directly as a fabric base material, is that the production of SCOBY in the kombucha fermentation process is difficult to achieve uniform thickness and

This nanocellulose production can then be developed into nanocellulose fibers in the form of threads and then spun to become a complete fabric. This method is expected to make fabrics from SCOBY to have characteristics that are more resistant to water. The more uniform structure of the nanocellulose can also make the nanocellulose fibers stronger and more compact so that they can be developed as fabrics

The manufacture of cellulose can be done in three ways, namely mechanically, acid hydrolysis and the help of cellulase enzymes. It is known that cellulase enzymes can be obtained through the growth of bacteria or specific fungi. One of the groups of fungi and bacteria commonly used to produce cellulase enzymes are *Trichoderma* and *Bacillus*. Both groups of fungi and bacteria are degrading cellulose microbes

SCOBY production in a large surface area is also difficult to stabilize [4].

with special needs, such as bullet-proof fabrics in the military field [5].

that commonly have habitats in soil [6].

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Naturally, cellulose fibers are most commonly found in plants. Cellulose fibers have an important role in the formation of cell walls in plants. It is known that most of the layers in the plant cell wall can be formed firmly due to the presence of the cellulose microfibrils (CMF) structure which is bound to each other between the cell wall layers. CMF can consist of 30–100 cellulose nanofibrils macromolecules with a modified 1,4-glycosidic extended chain bond, with a diameter ranging from 10-30 nm. CMF in plants naturally binds to hemicellulose through hydrogen bonds (**Figure 1**). This bond occurs to strengthen the structure of plant cell walls, where hemicellulose is known to act as a stabilizer between lignin and cellulose bonds [7].

Apart from plants, bacteria are also known to produce cellulose fibers well. Cellulose fibers produced from bacteria are known as Bacterial Cellulose (BC). BC is one of the primary metabolites produced by acetic acid bacteria, for example the genus of bacteria and *Acetobacter*. The acetic acid bacteria group is known to form a thick gel consisting of CMF and water, under certain fermentation conditions. The degree of polymerization that BC has is between 2000 and 6000. BC has several advantages over cellulose fibers in plants, including BC has a higher purity level, where BC does not contain hemicellulose and lignin. The characteristics of BC can also be modified into certain characters based on the content of microfibrils and cellulose crystallization, by modifying the fermentation conditions of acetic acid bacteria. The production of BC is known to require a shorter time than the production of cellulose fibers in plants, however BC and cellulose fibers in plants have the same molecular structure [8].

**Figure 1.** *Structure of cellulose in plants [7].*
