Financial Engineering
E-ISSN: 2945-1140
Volume 2, 2024
Methane Production from Poly(lactic Acid) (PLA) and Polyhydroxybutyrate (PHB) Biodegradable Plastics with Anaerobic Granulated Sludge
Authors: ,
Abstract: In this study, using Methanosarcina barkeri DSM 800 and Methanococcus vannielii DSM 1224 methanogenic bacteria under mesophilic $$(38 ± 1^{o}C)$$ and thermophilic $$(58 ± 1^{o}C)$$ conditions in anaerobic granulated sludge taken from Pakmaya Yeast Factory in Izmir, Turkey; Methane production from biodegradable plastics with poly(lactic acid) (PLA) and polyhydroxybutyrate (PHB) was investigated. Effect of different operating parameters, increasing biodegradation times (from 10 days to 500 days), different inoculum-substrate ratios (ISRs) (16, 8, 4, 2, 1) and increasing biochemical methane potential (BMP) times (between 10 day and 500 days) for the production of methane gas from PLA and PHB biodegradable plastics in anaerobic granular sludge waste; Methanosarcina barkeri DSM 800 and Methanococcus vannielii DSM 1224 methanogenic bacteria were operated during the anaerobic digestion process under anaerobic conditions at mesophilic $$(38 ± 1^{o}C)$$ and thermophilic $$(58 ± 1^{o}C)$$ experimental temperatures. PLA biodegradable plastics were operated at optimum pH=7.6. PHB biodegradable plastics were carried out at optimum pH=8.1. Predicting the biodegradation behavior of PLA and PHB biodegradable plastics with BMP tests; It is found that the ISR parameter plays a very important role. This study showed that temperature plays a key role in the aging of microorganisms (Methanosarcina barkeri DSM 800 and Methanococcus vannielii DSM 1224 methanogenic bacteria) during anaerobic digestion, the degradation of bioplastic materials (PLA and PHB) and the degradation of their natural properties. The increase in temperature from mesophilic conditions to thermophilic conditions increased the activities of methanogenic bacteria such as Methanosarcina barkeri DSM 800 and Methanococcus vannielii DSM 1224. The maximum cumulative $$CH_{4}(g)$$ production was measured at 630 NL $$CH_{4}$$ / kgVS for PHB biodegradable plastics in anaerobic granulated sludge with inoculum culture (the mixture of Methanosarcina barkeri DSM 800 and Methanococcus vannielii DSM 1224 methanogenic bacteria), at ISR=16 value, after 100 days, at pH=8.1 and at $$58±1^{o}C$$, respectively. The maximum 97% biodegradation efficiency was observed for PHB biodegradable plastics after 100 days, at pH=8.1 and at $$58±1^{o}C$$ thermophilic conditions, respectively.
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Keywords: Anaerobic granulated sludge, ANOVA statistical anaysis, Baker’s yeast, Biodegradable plastics, Methane production, Methanococcus vannielii DSM 1224, Methanosarcina barkeri DSM 800, Polyhydroxybutyrate (PHB), Poly(lactic acid) (PLA), Volatile fatty acids (VFAs).
Pages: 65-92
DOI: 10.37394/232032.2024.2.7