Microbial production of high value molecules using rayon waste material as carbon-source.

Rayon filaments composed of regenerated cellulose are used as reinforcement materials in tires and to a lower extent in the clothing industry as personal protective equipment e.g. flame retardant cellulosic based materials. After use, these materials are currently transferred to landfills while chemical degradation does not allow the recovery of the cellulose (as glucose) nor the separation of the high valuable flame-retardant pigment. In this study, rayon fibers were enzymatically hydrolyzed to allow recovery of glucose and valuable additives. The glucose was successfully used as carbon source for the production of high value compounds such as itaconic acid, lactic acid and chitosan. 14.2 g/L of itaconic acid, 36.5 g/L of lactic acid and 39.2 g/L of chitosan containing biomass were produced from Escherichia coli, Lactobacillus paracasei and Aspergillus niger, respectively, comparable to yields obtained when using commercial glucose as carbon source.

Highly Selective Enzymatic Recovery of Building Blocks from Wool-Cotton-Polyester Textile Waste Blends.

In Europe, most of the discarded and un-wearable textiles are incinerated or landfilled. In this study, we present an enzyme-based strategy for the recovery of valuable building blocks from mixed textile waste and blends as a circular economy concept. Therefore, model and real textile waste were sequentially incubated with (1) protease for the extraction of amino acids from wool components (95% efficiency) and (2) cellulases for the recovery of glucose from cotton and rayon constituents (85% efficiency). The purity of the remaining poly(ethylene terephthalate) (PET) unaltered by the enzymatic treatments was assessed via Fourier-transformed infrared spectroscopy. Amino acids recovered from wool were characterized via elementary and molecular size analysis, while the glucose resulting from the cotton hydrolysis was successfully converted into ethanol by fermentation with Saccharomyces cerevisiae. This work demonstrated that the step-wise application of enzymes can be used for the recovery of pure building blocks (glucose) and their further reuse in fermentative processes.