Transforming textile wastes into biobased building blocks via enzymatic hydrolysis: A review of key challenges and opportunities

Abstract

Textile waste generation in the United States represents approximately 17 million tons per year, constituting a serious environmental problem. Solutions to this situation have led to upcycling cotton-derived textile waste into value-added chemicals through enzymatic hydrolysis. Direct enzymatic treatment of cotton textile materials results in low yields given their high degree of crystallinity and the presence of dyes. Thus, several pretreatment methods have been proposed to improve performance in converting textile materials into glucose and other biobased building blocks. However, high yields are attained at the expense of high enzyme loads, energy usage, and chemical demands. This work reviews the reported literature and successful examples on pretreatment methods to transform cotton textile materials into glucose and its upcycling into biobased building blocks, focusing on the challenges when dyes are present in cotton garments. A comparison of the feasibility of such processes is overviewed from an economic and environmental standpoint. We end by discussing on the need to deploy less chemical intensive pretreatments and possible solutions for enzyme accessibility to cotton fibers.