A green strategy
that significantly accelerates the biodegradation
rate of cellulose acetate (CA) by triggering deacetylation was demonstrated.
Lipase isolated fromCandida rugosawas immobilized on CA particles (immobilized lipase (IL)) by a physical
entrapment method and further incorporated in CA films. After 40 days
of aging in contact with external enzymes (lipase and cellulase),
the number-average molecular weight (Mn) of CA/IL 5% decreased by 88%, while theMnof CA only exhibited a 48% reduction. Fourier transform infrared
and nuclear magnetic resonance spectroscopy of CA/IL 5% indicated
significant deacetylation, which was further supported by the decrease
of the water contact angle from 59 to 16°. These drastic changes
were not observed for CA. Similar differences in the degradation rate
were observed during aging under simulated composting conditions.
After 180 days of simulated composting, traces of CA/IL 5% were barely
observable, while large pieces of CA still remained. This could open
the door to modified lignocellulose materials with retained biodegradability,
also reducing the requirements for the degradation environment as
the process is initiated from inside of the material.