Microbial community acclimatization enhances bioplastics biodegradation and biogas production under thermophilic anaerobic digestion.

[Display omitted] • First study of microbial acclimation effects on bioplastics anaerobic digestion. • Inoculum acclimation to the substrate improves anaerobic digestion of bioplastics. • Enhanced growth of starch and PLA degraders increases bioplastic degradation. • Acclimation increased biogas production of starch-based bioplastic by 52%. • Acclimation increased biogas production of PLA-based bioplastic by 97%. This paper reports the results of a novel study of microbial acclimatization for bioplastics anaerobic degradation and conversion into biogas. Three sequential anaerobic digestion (AD) runs were carried out to favour microbial acclimatization to two different bioplastics, starch-based (SBS) and polyactic-acid (PLA). AD of SBS and PLA bioplastics was favoured by the acclimatization of the inoculum to the substrate after each run of AD. SBS conversion into biogas increased by 52 % (from 94 to 143 NL kgVS-1) and it was correlated with the enhanced growth of starch degrading bacteria such as Hydrogenispora, Halocella and Haloplasma. PLA anaerobic degradation increased by 97 % (from 395 to 779 NL biogas kgVS-1) and it was related to the acclimatization of known PLA-degraders such as Tepidimicrobium , Methanothermobacter and Tepidanaerobacter. Microbial acclimatization appears a suitable and low-cost strategy to enhance bioplastics circularity by promoting their anaerobic biodegradation and conversion into biogas. [ABSTRACT FROM AUTHOR]