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Unraveling the effects and mechanisms of microplastics on anaerobic fermentation: Exploring microbial communities and metabolic pathways

The Science of The Total Environment 2024 24 citations ? Citation count from OpenAlex, updated daily. May differ slightly from the publisher's own count.
Shuai Zhang, Xiao Huang, Wenyi Dong, Wenyi Dong, Z. Li, Jingsi Gao, Guorun Zhou, Xindong Teng, Kai Cao, Zhihao Zheng

Summary

Researchers investigated how five types of microplastics affect the anaerobic fermentation process used to treat sewage sludge. They found that polyethylene microplastics caused the greatest reduction in volatile fatty acid production, while polyvinyl chloride had the least impact, and all types disrupted microbial communities in distinct ways. The study suggests that microplastic contamination in wastewater could meaningfully interfere with sludge treatment efficiency.

Polymers

To investigate the effects of microplastics (MPs) on hydrolysis, acidification and microbial characteristics during waste activated sludge (WAS) anaerobic fermentation process, five different kinds of MPs were added into the WAS fermentation system and results indicated that, compared to the control group, the addition of polyvinyl chloride (PVC)-MPs exhibited the least inhibition on volatile fatty acids (VFAs), reducing them by 13.49 %. Conversely, polyethylene (PE)-MPs resulted in the greatest inhibition, with a reduction of 29.57 %. MPs, while accelerated the dissolution of WAS that evidenced by an increase of lactate dehydrogenase (LDH) release, concurrently inhibited the activities of relevant hydrolytic enzymes (α-Glucosidase, protease). For microbial mechanisms, MPs addition affected the proliferation of key microorganisms (norank_f_Bacteroidetes_vadinHA17, Ottowia, and Propioniclava) and reduced the abundance of genes associated with hydrolysis and acidification (pfkb, gpmI, ilvE, and aces). Additionally, MPs decreased the levels of key hydrolytic and acidogenic enzymes to inhibit hydrolysis and acidification processes. This research provides a basis for understanding and unveils impact mechanisms of the impact of MPs on sludge anaerobic fermentation.

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