Experimental study demonstrates microbial synthesis of biodegradable thermoplastics from cotton textile waste, highlighting a sustainable upcycling route for household discards.
Key Points
To evaluate the feasibility of upcycling post-consumer cotton household textiles into poly(3-hydroxybutyrate) [P(3HB)], a biodegradable and biocompatible thermoplastic, via microbial fermentation.
Post-consumer cotton towels were mechanically defibrillated, pre-treated by freezing in a sodium hydroxide/urea mixture, and enzymatically hydrolyzed using Cellic® CTec3 cellulase.
The derived cotton hydrolysate was supplied as the primary glucose carbon source (initial concentration of 40 g/L) for batch bioreactor cultivation of Burkholderia thailandensis E264.
Enzymatic saccharification achieved a glucose yield of 102.3 g/L, supporting a peak P(3HB) concentration of 9.17 ± 1.01 g/L after 53 h of fermentation with a volumetric productivity of 0.165 g/(L h) and yield of 0.218 g/g.
The synthesized P(3HB) showed an average molecular weight of 497 kDa, polydispersity index of 2.6, melting temperature of 170 °C, thermal degradation temperature of 291 °C, and crystallinity index of 78.8%.
Mechanical testing revealed a Young's modulus of 563 ± 62 MPa and tensile strength of 27 ± 2 MPa, matching performance metrics of commercial P(3HB) thermoplastics.