Background: Renowned oil-based polymers represent
an environmental nuisance, due to their well-known
permanency in nature, known to disrupt ecosystems.
In response, bio-based polymers have emerged as an
alternative, providing a sustainable blueprint for
plastic circularity1. However, despite being classified
as biodegradable, these polymers can still show
resistance to biodegradation when not presented
with optimal environmental conditions such as
specific temperature and pH, amongst other key
factors in their breakdown. Due to this, microbial
degradation results in an interesting path to promote
biodegradation of such polymers.2
Objective: This study aims to evaluate the ability of
selected strains isolated from polluted environments
to improve the rate of biopolymers’ biodegradation
such as Polyhydroxy butyrate (PHB), Polylactic acid
(PLA), and Bacterial cellulose (BC) when exposed to
strains with specific enzymatic tools to aid in its
degradation.
Methods: Selected strains were previously isolated
from plastic-polluted soil samples. Strains were
transferred to Mineral Salt media (MSM) biopolymersupplemented
plates (7d, 30℃) (MSM (15 g/l Agar, 9
g/l Na2HPO4 x 12H2O, 1.5 g/l KH2PO4, 1 g/l NH4Cl,
0.2 g/l MgSO4 x 7H2O, 0.2 g/l CaCl2 x 2H2O,
Fe(III)NH4-citrate 0.0012 g/l), (1-3%) biopolymers
(PHB, BC, and PLA) growth and clear-zone method
were used to determine strains’ possible enzymatic
activity. Selected strains were transferred to flasks
containing PHB, PLA, and BC films, respectively, in
MSM and incubated for 20 days at 30℃, 120 rpm.
Samples were washed and dried and their level of
degradation was assessed by FTIR, weight loss, and
scanning electron microscopy (SEM). The ability of the
best performer strain to degrade PHB was
additionally assessed using Respirometer (Echo
Instruments) to determine the biodegradability of
said films under a controlled temperature (25°C) with
a flow rate of 500ml/min.
Results: Significant weight loss was observed in
samples exposed to strains, meaning biodegradability
was achieved in an important percentage, proving
their capability to degrade the proposed
biopolymers, compared to samples lacking microbial
presence.10th International Conference of MIKROBIOKOSMOS, Larissa from 30 Novewmber to 2 December 2023
