## 5 Challenges and Opportunities with Alternative Feedstocks for L-MMCF  
Despite challenges with the use of alternative feedstock for L-MMCF production, there is a definite demand for them. The current global production of textile fibres is approximately 100 million tonnes per year, with the largest production being polyester at 54% and cotton at 22% [7; 12; 120]. L-MMCF is less than 0.3% global production, whereas viscose is at 5% [12]. Global consumption per capita is growing at a rate of approximately 3% per year [121]. From a sustainability perspective, textile production is not only resource intensive, but consumers are also less willing to keep textile items long term. It is estimated that Canadian consumers landfill 500,000 tonnes of textiles per year, averaging 12 kg per person [122]. With global textile consumption on the rise, and with cotton being one of the largest consumed textiles, the textile industry is facing a phenomenon termed the Cellulose Gap [6; 7]. It is estimated that cotton production is now at maximum capacity at 26 million tonnes per year, primarily due to a decline in global arable land, but the global demand is 45.9 million tonnes [6; 123; 124]. Cotton is also a water-intensive crop. An example of this is the water utilisation from the Aral Sea for irrigation of cotton crops in Central Asia,  
Figure 7: Illustration of the L-MMCF dry jet-wet spinning process (reproduced from [20] with permission from Elsevier). which in the 1960's was recorded as the fourth largest lake in the world [125; 126; 127]. It is now estimated to be 10% of its original size. There are other sources of seed fibre towards direct textile production. Unfortunately, these fibres are either too short (e.g., kapok and milkweed) or too coarse (e.g., coir) for staple fibre spinning and are utilised more towards nonwoven and household textile applications [128; 129]. Bast fibres, such as those found in industrial hep and flax, can be processed into textiles; however, additional processes are often required to \"cottonise\" the fibre so it can be used in consumer textile applications [41; 130; 131; 132]. Additionally, these fibres are often blended with cotton or synthetic fibres to improve mechanical properties. MMCFs are a solution to fill the cellulose demand. Viscose is manufactured via a cellulose derivatisation process where carbon disulphide is utilised in the xanthation process [7]. Carbon disulphide is extremely environmentally damaging and harmful to human health; as such, there are manufacturing restrictions in developed countries [133]. Viscose is primarily manufactured in China, India, and Indonesia [134]. L-MMCF, which is a relatively new fibre in comparison to viscose, utilises NMMO, which is considered an environmentally friendly process [7]. Due to increased manufacturing regulations and restrictions [135; 136; 137], it is expected that L-MMCF will surpass viscose manufacturing in the near future. Figure 8 illustrates the difference between the rayon viscose and L-MMCF manufacturing process, highlighting the environmental implications of viscose manufacturing through the use of carbon disulphide and production of toxic effluent; in comparison, the L-MMCF manufacturing incorporates solvent recovery to substantially reduce environmental impact [138]. Figure 8: The viscose MMCF and L-MMCF processes (reproduced from [138] with permission from Elsevier). Lyocell man-made cellulosic fibres are typically manufactured from wood (i.e., beech and eucalyptus trees) and bamboo sources, which lead to issues of deforestation [7; 139]. The use of alternative sources of cellulose (e.g., industrial hemp), particularly residual straw from cereal and oilseed crop production, towards the L-MMCF process addresses deforestation and can lead to improvements in the environment and sustainability initiatives. Utilisation of locally sourced feedstock allows for complete traceability of fibre from feedstock source to end use application.