Microbiological Degradation of Poly(3-Hydroxybutyrate) Films in Different Edaphoclimatic Zones of Siberia

Abstract

The urgency of handling plastic waste is escalating every year and the problem can be only solved using an integrated approach. Replacing non-degradable materials synthesised from fossil fuels with carbon-neutral biopolymers can reduce non-biodegradable waste, CO2 emissions and energy use. However, even completely biodegradable biopolymer materials will stay in the environment for a long time since the rate of their biodegradation depends on many factors. The paper evaluates the influence of edaphoclimatic and microbiological factors on the biodegradation rate of biopolymer films from the poly(3-hydroxybutyrate) [P(3HB)] when exposed to soddy-carbonate, cryogenic, and agrogenically transformed Siberian soils. A principal component analysis showed that in different soils, characterised by specific temperature, moisture content, pH values, biogenicity and abundance of microorganisms, the kinetics of mass loss of P(3HB)-films were primarily determined by the temperature- precipitation ratio and it increased as the content of humus in soil increased. The maximum rates of film mass loss of 0.63 ± 0.09 and 0.93 ± 0.01 mg ∙ day-1 were detected in agrogenic soils. No correlation between mass loss of the films and the total number of microorganisms was found. A phylogenetic analysis revealed differences in the composition of primary P(3HB)-degrading microorganisms in different soil types