Construction of polylactic acid plastisphere microbiota for enhancing nitrate reduction in denitrification biofilters

Yanxi Chen; Mengzhen Huang; Yue Fu; Tianyu Gao; Zhihao Gan; Fangang Meng

doi:10.1016/j.biortech.2024.131853

Construction of polylactic acid plastisphere microbiota for enhancing nitrate reduction in denitrification biofilters

Bioresour Technol. 2024 Nov 20:417:131853. doi: 10.1016/j.biortech.2024.131853. Online ahead of print.

Authors

Yanxi Chen¹, Mengzhen Huang¹, Yue Fu¹, Tianyu Gao¹, Zhihao Gan¹, Fangang Meng²

Affiliations

¹ School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology (Sun Yat-sen University), Guangzhou 510275, PR China.
² School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology (Sun Yat-sen University), Guangzhou 510275, PR China. Electronic address: mengfg@mail.sysu.edu.cn.

PMID: 39577778
DOI: 10.1016/j.biortech.2024.131853

Abstract

Developing methods for reusing biodegradable plastics, like polylactic acid (PLA) straws, is highly needed. Here, PLAs were applied to substitute traditional commercial ceramic media (CCM) in denitrification biofilters. During long-term operation, replacing CCM with PLA significantly enhanced nitrate removal efficiency from 32.68-54.39 % to 41.64-66.26 %. Ammonia nitrogen effluent maintained below 0.5 mg/L in all reactors. PLA plastisphere shaped unique microbial communities, i.e., denitrifying bacteria Bacillus, Pseudomonas and Acidovorax preferred to inhabit or degrade PLA. Compared to CCM biofilms, PLA diminished the importance of stochastic process in biofilm assembly of PLA plastisphere. Metagenomic sequencing suggested that PLA biofilms possessed greater metabolic capabilities of denitrification and glycolysis compared to CCM. Additionally, Bacillus strain P01 isolated from PLA plastisphere demonstrated strong PLA depolymerization. Overall, this study revealed that PLA serves as carbon source and biofilm carrier, offering a promising approach to integrating plastic reuse with wastewater treatment.

Keywords: Biodegradable plastics; Denitrification; Microbial community structure; Polylactic acids; Wastewater treatment.