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

This paper reports the results of a novel study of microbial acclimatization for bioplastics anaerobic degradation andconversion into biogas. Three sequential anaerobic digestion (AD) runs were carried out to favour microbialacclimatization 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 eachrun of AD. SBS conversion into biogas increased by 52 % (from 94 to 143 NL kgVS-1) and it was correlated withthe enhanced growth of starch degrading bacteria such as Hydrogenispora, Halocella and Haloplasma. PLAanaerobic degradation increased by 97 % (from 395 to 779 NLbiogas kgVS-1) and it was related to the acclimatization of known PLA-degraders such as Tepidimicrobium, Methanothermobacter and Tepidanaerobacter. Microbialacclimatization appears a suitable and low-cost strategy to enhance bioplastics circularity by promoting theiranaerobic biodegradation and conversion into biogas.