Abstract:
Biodegradation is one of the strategies for the handling of PET bottle waste by
involving the activity of microorganisms, such as bacteria. In this study, the
thermophilic bacteria LBKURCC191, 192, 193, 194, 195 and 196, which have been
isolated from hot springs of Bukik Kili, Solok-Sumatera Barat, acts as degrading agents
for PET bottles. The six bacteria isolates were tested for their ability to degrade mineral
water bottles “Le Minerale” using the solid fermentation method for four weeks.
LBKURCC191 (Bacillus sp) was isolate with the highest percentage of PET weight
loss. These bacteria were able to degrade PET up to 0,620% on NA media and 0,443%
on MSM media. SEM analysis on PET incubated with LBKURCC191 bacteria showed
changes of surface structure to become rough, bumpy and uneven due to enzyme
activity by bacteria during incubation. FTIR analysis showed shifting of wavenumber to
a lower value in the absorption of ester, alcohol and C-H aliphatic, so the bond length
increased and bond strength decreased. This fact shows the stretching of the bonds on
several functional groups in the PET structure due to the activity enzymes produced by
bacteria for degradation.
