Research Information System
V. International Enzyme and Bioprocess Days, İzmir, Turkey, 27 - 29 August 2024, pp.55, (Summary Text)
The production of plastics has steadily increased since the mid-twentieth century because they make
life easier and are very useful for industries. However, plastics accumulate uncontrollably in terrestrial
and marine ecosystems due to their inability to be effectively recycled or degraded at the end of their
lifetime. Even if they remain intact in nature for centuries due to their hydrophobic structure.
Therefore, the degradation of plastics has become one of the main issues on nations' social and political
agendas. In the present study, a putative esterase family gene from Bacillus tequilensis with PCL
degrading ability was cloned into pET20b(+) and expressed in E. coli BL21(DE3). Expressed enzyme
was also partially characterized, and its plastic degradation ability was evaluated. The enzyme showed
maximum activity at pH 7 and 40 °C. Mg2+ and Fe2+ increased the enzyme activity by 20-25%, while
Ba2+ and Ni2+ caused a significant decrease in enzyme activity.
The degradation ability of the studied enzyme on polylactic acid (PLA), crystalline polyethylene
terephthalate (cPET), and amorphous polyethylene terephthalate (aPET) were evaluated by assessing
weight loss and changes in the polymers' average molecular weights, as determined by gel permeation
chromatography (GPC). Although slight degradation was observed in some repetitions for PLA and
PET, the standard error values were very high. Therefore, it was interpreted that the enzyme had no
significant affinity towards PLA, cPET, and aPET. However, the enzyme showed a degradation ability
against polycaprolactone PCL with 14% weight loss.