Enzymatic hydrolysis of poly(1,4-butylene 2,5-thiophenedicarboxylate) (PBTF) and poly(1,4-butylene 2,5-furandicarboxylate) (PBF) films: A comparison of mechanisms

Matteo Gigli,Felice Quartinello,Michelina Soccio,Alessandro Pellis,Nadia Lotti,Georg M Guebitz,Silvia Licoccia,Andrea Munari

doi:10.1016/j.envint.2019.05.046

Abstract

Enzymatic hydrolysis of poly(1,4-butylene 2,5-thiophenedicarboxylate) (PBTF) and poly(1,4-butylene 2,5-furandicarboxylate) (PBF) by Humicola insolens (HiC) and Thermobifida cellulosilytica (Cut) cutinases is investigated. For the first time, the different depolymerization mechanisms of PBTF (endo-wise scission) and PBF (exo-wise cleavage) has been unveiled and correlated to the chemical structure of the two polyesters.

Highlights

The constantly emerging problems deriving from plastic pollution such as the accumulation of manmade materials in the great pacific garbage patch and the increasing amounts of polymers accumulated by wildlife are a current threat to our planet Earth that needs to be tackled by mankind in a timely manner (Lebreton et al, 2018; Foekema et al, 2013).Efforts in this direction have already been made especially from Europe that plans a ban of certain products and a consumption reduction for other goods
PBTF chains (Tg = 25 °C) are more mobile than PBF (Tg = 39 °C) ones, because of the lower glass transition temperature, in turn caused by the weaker interchain interactions, as previously observed (Guidotti et al, 2018d)
Following recent works that demonstrated the efficient degradation of amorphous PEF using cutinases, (Weinberger et al, 2017a; Weinberger et al, 2017b) in this study we compared the hydrolysis of PBTF and PBF by two different enzymes, a commercial cutinase from Humicola insolens (HiC) and the thermostable Thermobifida cellulosilytica cutinase 1 (Cut)

Summary

Introduction

The constantly emerging problems deriving from plastic pollution such as the accumulation of manmade materials in the great pacific garbage patch and the increasing amounts of polymers accumulated by wildlife are a current threat to our planet Earth that needs to be tackled by mankind in a timely manner (Lebreton et al, 2018; Foekema et al, 2013). (https://www.coca-cola.co.uk/faq/what-is-plantbottle, n.d.) Researchers around the world are trying to derive the diacid component, terephthalic acid (TA), from renewable resources, (Pellis et al, 2016a) or focus on the development of biobased TA-free polyesters. In this framework, the most well-known example is 2,5-furandicarboxylic acid (FDCA), already obtainable from biomass at large scale (Kim et al, 2018; de Jong et al, 2012). The hydrolysis mechanism associated to the used biocatalysts was elucidated (Scheme 1)

Results and discussion

Materials

Protein quantification and esterase activity assay

Enzymatic hydrolysis of PBF and PBTF thin films

Conclusions

Funding sources