Precision-controlled breakdown of biopolymers – optimization of enzymatic degradation process for sustainable production of binders with desirable physicochemical properties

Sammanfattning

Non-woven materials produced via the chemical bonding technique require the addition of binders to achieve desired physicochemical properties. Traditionally, these binders contain synthetic polymers such as polypropylene and polyethylene, but recent demands for green alternatives, i.e. biobinders, have incited the use of biobased materials instead, such as biopolymers. Like most biomaterials, biopolymers can be depolymerized by enzymes, to give the biobinder appropriate qualities. This study investigates the possibility to incorporate an enzymatically degraded biopolymer into one such biobinder. After an initial literature study, the enzyme enzyme 2 was primarily chosen to work with. Optimisation revealed enhanced performance of the enzyme at 50°C, pH ≈6–7 and a dosage of 0.15 Uenzyme/gbiopolymer when added to a ≈10% w/w biopolymer-solution. Results were quantified through timely spaced viscosity measurements of the treated samples, as well as measurements of absorbance by the DNS-method. Additionally, the effects of the enzyme on the biopolymer’s smallest structures were visualised through SEM. Attempts were also made to inhibit the enzyme through heat, but these tests were not so successful, likely due to the viscous nature of the biopolymer-solution. Finally, a ≈10% w/w biopolymer solution, treated with 0.15 Uenzyme/gbiopolymer, was incorporated into a biobinder. The viscosity of this biobinder was significantly lower than the binder containing native biopolymer, demonstrating that the enzymatic treatment was successful. That being said, further efforts need to be made to identify reliable methods of enzyme inhibition and alternative enzymes for the depolymerization itself.