Promotion of polylactide degradation by ammonia under hyperthermophilic anaerobic conditions

Co-digestion of polylactide and kitchen garbage in hyperthermophilic and thermophilic continuous anaerobic process

“…Both of the PCOD dissolution ratio and PLA transformation ratio in the hyperthermophilic reactors were linearly related with the ammonia concentration as shown in Runs b7 to b9 and Runs c7 to c9. These results accorded with the previous research conducted with batch experiments (Wang et al, 2011). The pretreatment with ammonia solution can promote the dissolution of biomass waste such as lignin and hemicellulose before the subsequent fermentation (Kurakake et al, 2001;Lee et al, 2010).…”

“…5 (a, b)). This accorded with the previous researches results that higher temperature was favorable for PLA biodegradation (Copinet et al, 2004;Itavaara et al, 2002;Wang et al, 2011).…”

“…HRT in the hyperthermophilic reactors for single pass was set at 1 d, and this did not possibly affect the microbial diversity. Wang et al (2011) showed that PLA degradation was partially contributed by biological and/or enzyme activity in the hyperthermophilic treatment by the batch experiments. This hyperthermophilic treatment does not require special bacteria adapted to this extreme temperature condition, but bacteria in the thermophilic condition can be utilized, so the hyperthermophilic solubilization can be easily installed to traditional thermophilic anaerobic digestion plants.…”

“…Supposing that PLA is able to be degraded via enzymatic reactions under temperature and pressure acceptable for AD process with existence of ammonia, the hydrolysis product of protein, PLA is expected to be transformed to methane easily. Wang et al (2011) performed batch experiments and demonstrated that PLA was hydrolyzed under hyperthermophilic pretreatment with ammonia addition and converted to methane by methanogens under the following thermophilic anaerobic conditions. However, few researches focusing on PLA biodegradation with ammonia under continuous anaerobic operation have been published to date and the optimum configuration of the system including hyperthermophilic treatment is poorly understood.…”

Can anaerobic digestion be a suitable end-of-life scenario for biodegradable plastics? A critical review of the current situation, hurdles, and challenges

“…Two types of plastic bags (100% PLA and 70% PLA) were used as pieces that were 2 x 2 x 0.1 mm in size. The methane conversion ratios of the two-phase systems were 82.9% and 80.8%, respectively, which was higher than the 70.1% conversion ratio of the single-phase system (Wang et al, 2011). Dolci et al, (2022) have also recently investigated the semi-continuous co-digestion tests of two MaterBi® biodegradable bags together with food wastes (11/91 % in term of DCO).…”