Biotechnology for manufacture and modification of cellulosic fibres

An increasing interest in the protection of the natural enviromnent was manifested at the close of the twentieth century and continues in the early twenty-first century. Many different industrial technologies are characterised by the emission of highly dangerous substances, e.g. carbon disulfide and hydrogen sulphide, which continue to poison the environment. 

Due to the environmental risk caused by the use of carbon disulphide in the viscose process, attempts have been made to develop new types of processes for fibre production from cellulose, such as pulp directly dissolved in organic solvents, e.g. A -methylmorpholine-Af-oxide (NMMO) application of cellulose derivatives such as cellulose carbamate and dissolving pulp in aqueous sodium hydroxide (biotransformed pulp).  

Apparently, it is extremely difficult to dissolve cellulose safely in a simple and cheap solvent and accordingly, there exists a need for a process capable of manufacturing cellulosic products economically and in an environmentally acceptable maimer. This is especially important for improving sustainability and for reducing environmental and health impacts of the industry producing shaped cellulosic articles. 

The benefits of biotransformed cellulose pulp (discussed in Section 4.3) in connection with its technological simplicity and economical effectiveness promote this biotechnological method as the most useful way of processing pulp into fibres. The modification of cellulose structure during biotransformation has definitely improved the main properties of cellulose pulp such as solubility in aqueous sodium hydroxide and chemical reactivity leading towards obtaining  

There are great opportunities to obtain the most reactive biotransformed cellulose, which can be utilised for preparation of cellulosic products such as fibres, films, derivatives, sponges, etc. The enzymatic transformation of pulps into direct soluble cellulose (Celsol) is shown schematically in Fig. 4.21. 

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