Effects of chemical pretreatment on the enzymatic hydrolysis of post-consumer waste viscose†

Abstract

The pretreatment of post-consumer waste viscose before enzymatic hydrolysis was tested and evaluated to develop a tertiary recycling strategy for waste viscose, as no such strategy currently exists. There were differences between hydrolyzability of pre-consumer and post-consumer viscose, as we obtained 100% glucose yield from pre-consumer viscose while only 60–80% could be achieved from post-consumer, which we attributed to the inhibition – induced by contaminants that accumulated in the post-consumer viscose during its manufacture and use. Dilute alkali and acid pretreatment were applied to improve the hydrolysis of post-consumer viscose, although both of them proved unsuccessful strategies as alkali and acid pretreatment reduced glucose yield up to 28% and 44%, respectively. We concluded that avoiding pretreatment altogether was the most energy-efficient and resource-efficient alternative with regard to the saccharification of waste viscose. Thus, the economic viability of (enzymatically) saccharifying waste viscose depends entirely on the inherent hydrolyzability of the feedstock and its price.