Issue 05/2023

Fibres / Textiles
Mushroom fibres for textiles
Chitosan for the textile industry obtained from fungal biomass
The textile sector is facing a turning point: It is
already clear that one of the most important market
drivers of the future will be the growing demand for
environmentally friendly textiles. This is shown by a look at
neighbouring sectors such as the food industry, which is
increasingly relying on organic products. However, the share
of biobased fibres in the textile industry does not yet reflect
this trend. Quite the opposite: for decades, the worldwide
consumption of synthetic fibres has been rising continuously.
On the one hand, this is due to the increased functionality
of polyester fibres in recent years and on the other hand, due
to the low production costs. The raw material for these fibres
is crude oil, the price of which has remained at a constantly
low level for years and ensures that cheap synthetic fibres
flood the textile market.
The environmental impact is huge: greenhouse gas
emissions during production, growing mountains of textile
waste for disposal, and microplastic pollution of the oceans,
to name but a few. Cotton, as a widespread alternative, is
hardly less harmful to the environment: from the use of
toxic pesticides during production to the immensely high
water and energy consumption during processing, the
environmental balance sheet of this textile raw material
source hardly looks any better.
Environmentally friendly alternatives are therefore urgently
needed. Of all the natural fibre base materials, cellulose as a
plant fibre has seen the fastest increase in all textile substrates
in recent years, as it is the most abundant biopolymer on
earth. The second most naturally occurring polymer is chitin.
While cellulose is a polymer of glucose, chitin is a polymer of
the closely related molecule N-acetylglucosamine. It is the
main component of the cell walls of fungi and is also found in
nature in caterpillar skins, butterfly wings, the exoskeleton
of insects or in a strong mixture with calcium carbonate in
crab and crustacean shells. Chitosan can be obtained by the
deacetylation of chitin.
In the past 20 years, several chitin extraction plants have
been built, mainly in the Asia-Pacific region and in Japan,
using a raw material obtained from transformed shrimp
and crab shells. In Europe, there is practically no production
of chitin or chitosan today. The remarkable properties of
chitosan such as biodegradability, antibioticity (inhibition of
bacterial growth), and compatibility with cotton and cellulose
make it a promising bioplastic for the production of synthetic
fibres for textile applications.
The production volume of chitin and chitosan is mainly
limited by the availability of the biological feedstock.
Worldwide demand for chitin in 2015 was above 60,000
tonnes, worldwide production of chitin the same year was
Mould
(Aspergillus Niger)
Gene modification,
cultivation and
fermentation
Extraction and
deacetylation
Solvent
spinning
Yarn development Fabric development Product prototyping
20 bioplastics MAGAZINE | Renewable Carbon Plastics [05/23] Vol. 18