I was stumbling upon an article about the usage of biotechnology within fashion. For example, the usage of spider silk through genetic engineering. Also, spider silk is biodegradable and considered a strong, flexible, and lightweight material. It has been used for luxury watch straps and Adidas is experimenting with it.
Another sustainable alternative for fashion is the using algae for dyes since many dyes are created with chemicals which can be harmful to the environment. Another alternative offered has been bacteria to dye clothing.
Fungi can be used to make clothing too such as a belt sourced from mushrooms.
These are great alternatives that unfortunately do require more research and funding since it seems these are budding ventures. However, fashion does contribute to lots of waste and the usage of fossil fuels especially in the fast fashion industry.