Anaerobic co-digestion of three commercial bio-plastic bags with food waste: Effects on methane production and microbial community structure

Cheng Yu; Bi Dongsu; Zhang Tao; Jiang Xintong; Chen Ming; Wang Siqi; Shen Zheng; Zhang Yalei

doi:10.1016/j.scitotenv.2022.159967

Anaerobic co-digestion of three commercial bio-plastic bags with food waste: Effects on methane production and microbial community structure

Sci Total Environ. 2023 Feb 10;859(Pt 1):159967. doi: 10.1016/j.scitotenv.2022.159967. Epub 2022 Nov 5.

Authors

Cheng Yu¹, Bi Dongsu², Zhang Tao³, Jiang Xintong¹, Chen Ming¹, Wang Siqi¹, Shen Zheng⁴, Zhang Yalei⁵

Affiliations

¹ Institute of New Rural Development, Tongji University, Shanghai 200092, China; School of Chemistry and Environmental Engineering, Shanghai Institute of Technology, Shanghai 200233, China.
² School of Chemistry and Environmental Engineering, Shanghai Institute of Technology, Shanghai 200233, China.
³ College of Design and Innovation, Tongji University, Shanghai 200092, China.
⁴ Institute of New Rural Development, Tongji University, Shanghai 200092, China. Electronic address: shenzheng@tongji.edu.cn.
⁵ College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.

PMID: 36347286
DOI: 10.1016/j.scitotenv.2022.159967

Abstract

The emergence of bioplastic bags as a replacement for traditional petroleum-based plastic bags is promising for their simultaneous anaerobic digestion with food waste. In this study, the degradation of three bioplastic bags is evaluated during anaerobic co-digestion with food waste under mesophilic/thermophilic conditions, and the results indicated PBAT/PLA/starch > PLA > PBAT for methane production rate. The PBAT/PLA/starch mixture produced 23.4 ml/g of methane at 55 °C, and the cumulative methane production increased by 28.4 % compared to the control. In addition, the lag time before methane production was reduced by one to four days when anaerobic co-digestion was performed under thermophilic conditions, and the conversion of the bioplastics improved by 9.11-11.2 %. Microscopy further showed obvious physical degradation of the PBAT/PLA/starch material. The FTIR analysis showed that the characteristic peaks of the material at 3320, 2957, and 934 cm^-1 decreased significantly after anaerobic fermentation. The biodegradability of the polymer decreased with an increase in the content of the crystalline area in the structure. The addition of a comonomer reduced the crystallinity of the polymer. In addition, the biodegradability was increased by adjusting the hydrolysis reaction and microbial activity of the polymer surface. An analysis of the structural features of the microbial communities revealed that Archaea exhibited different biodiversity at distinct temperatures. In particular, under thermophilic conditions, the relative abundance of Methanothermobacter was 56.0 %, and it plays an important role in the anaerobic degradation of PBAT/PLA/starch materials, while bacterial communities showed smaller differences. Overall, the bioplastic was able to be co-digested anaerobically with food waste to produce renewable energy. This study provides a plan for the practical application of biodegradable plastic bag collection for the combined treatment of food waste in anaerobic digesters. It provides a theoretical basis for modifications of bioplastic and domestication of anaerobic microorganisms.

Keywords: Anaerobic digestion; Biogas; Bioplastics; Food waste; Microbial community structure.

MeSH terms

Anaerobiosis
Bioreactors
Food
Methane
Methanobacteriaceae
Microbiota*
Polymers
Refuse Disposal*
Sewage / microbiology
Starch

Substances

Methane
Starch
Polymers
Sewage