Anna Kowalczyk
Jagiellonian University, Poland
Title: High density polyethylene and polylactide biodegradation by microorganisms – preliminary studies
Biography
Biography: Anna Kowalczyk
Abstract
This study present results of microbial activity towards polylactide (PLA) and high density polyethylene (HDPE) degradation.
Th ree selected from environment microorganisms species were used in project i.e. Achromobacter xylosoxidans PE-1 for HDPE
and two species of mold, i.e. Aspergillus niger and Penicillium minioluteum for PLA. Th ree types of the PLA were tested: two with
starch modifi cation (20% - PLA20 and 50% - PLA50) and one unmodifi ed PLA. Th e samples of plastic fi lm were incubated in liquid
mineral medium inoculated with isolated strains. Th e chemical structure changes of the samples were analyzed by Attenuated Total
Refl ectance Fourier Transform Infrared Spectroscopy (ATR-FTIR). Structure and the surface of the plastic fi lms was monitored by
Scanning Electron Microscope (SEM). Additionally, weight loss of samples was controlled. Th e greatest weight loss (about 20%)
was observed for the PLA and it was two times higher than for the PLA20. About 9% loss of weight was also detected as a result of
A. xylosoxidans PE-1eff ect on HDPE fi lm. FTIR analysis showed visible changes of spectra of PLA and HDPE samples treated with
microorganisms, as the signal intensity indicated the reorganization of bonds and new bonds in tested range of the spectra were
observed. Th e SEM photographs of bacteria and mold strains treated samples also demonstrated changes of the fi lm structure which
was visibly rough in comparison to smooth surface of the control samples, and the higher was the content of starch in the case of PLA,
the more damaged was the fi lm sample.