APESA, Pôle Valorisation, 64121 Montardon, France; Université de Pau et des Pays de l'Adour / E2S UPPA / CNRS, IPREM UMR5254, Institut des Sciences Analytiques et de Physicochimie pour l'Environnement et les Matériaux, Chimie et Microbiologie de l'Environnement, 64000, Pau, France.
Université de Pau et des Pays de l'Adour / E2S UPPA / CNRS, IPREM UMR5254, Institut des Sciences Analytiques et de Physicochimie pour l'Environnement et les Matériaux, Chimie et Microbiologie de l'Environnement, 64000, Pau, France.
J Environ Manage. 2022 Dec 15;324:116369. doi: 10.1016/j.jenvman.2022.116369. Epub 2022 Oct 3.
The influence of the inoculum-substrate ratio (ISR) on the mesophilic and thermophilic biochemical methane potential test of two biodegradable plastics was evaluated. Poly(lactic acid) (PLA) and polyhydroxybutyrate (PHB) were selected for this study, the first for being recalcitrant to mesophilic anaerobic digestion (AD) and the second, by contrast, for being readily biodegradable. Several ISRs, calculated on the basis of volatile solids (VS), were tested: 1, 2, 2.85, 4, and 10 g(VS of inoculum).g(VS of substrate). A high ISR was associated with an enhanced methane production rate (i.e., biodegradation kinetics). However, the ultimate methane production did not change, except when inhibition was observed. Indeed, applying the lowest ISR to readily biodegradable plastics such as PHB resulted in inhibition of methane production. Based on these experiments, in order to have reproducible degradation kinetics and optimal methane production, an ISR between 2.85 and 4 is recommended for biodegradable plastics. The active microbial communities were analyzed, and the active bacteria differed depending on the plastic digested (PLA versus PHB) and the temperature of the process (mesophilic versus thermophilic). Previously identified PHB degraders (Ilyobacter delafieldii and Enterobacter) were detected in PHB-fed reactors. Thermogutta and Tepidanaerobacter were detected during the thermophilic AD of PLA, and they are probably involved in PLA hydrolysis and lactate conversion, respectively.
研究了接种物-底物比（ISR）对两种可生物降解塑料的中温及高温生物化学甲烷潜能试验的影响。选择聚乳酸（PLA）和聚羟基丁酸酯（PHB）进行这项研究，前者难以进行中温厌氧消化（AD），后者相反，容易生物降解。测试了几种基于挥发性固体（VS）计算的 ISR：1、2、2.85、4 和 10 g（接种物 VS）。g（底物 VS）。高 ISR 与甲烷生成速率（即生物降解动力学）的增强有关。然而，除了观察到抑制作用外，最终甲烷产量并没有变化。事实上，对于 PHB 等易生物降解的塑料，应用最低 ISR 会导致甲烷生成受到抑制。基于这些实验，为了获得可重复的降解动力学和最佳的甲烷产量，建议可生物降解塑料的 ISR 在 2.85 到 4 之间。分析了活性微生物群落，活性细菌因消化的塑料（PLA 与 PHB）和工艺温度（中温与高温）而异。在 PHB 喂养的反应器中检测到先前鉴定的 PHB 降解菌（Ilyobacter delafieldii 和 Enterobacter）。在 PLA 的高温 AD 过程中检测到 Thermogutta 和 Tepidanaerobacter，它们可能分别参与 PLA 水解和乳酸转化。
