Do Soil pH Levels Drive the Responses of Catalase Activity and Bacterial Communities to Microplastics? A Case Study in Mollisols

Yin, Yuan; Wu, Xiangyu; Ren, Qina; Guo, Yuxin; Yue, Zhonghui; Bai, Xin; Xu, Jia; Wang, Pengwei

doi:10.3390/toxics13121005

Open AccessArticle

Do Soil pH Levels Drive the Responses of Catalase Activity and Bacterial Communities to Microplastics? A Case Study in Mollisols

by

Yuan Yin

,

Xiangyu Wu

,

Qina Ren

,

Yuxin Guo

,

Zhonghui Yue

^*,

Xin Bai

^*

,

Jia Xu

and

Pengwei Wang

College of Life Science and Technology, Harbin Normal University, Harbin 150025, China

^*

Authors to whom correspondence should be addressed.

Toxics 2025, 13(12), 1005; https://doi.org/10.3390/toxics13121005

Submission received: 4 October 2025 / Revised: 3 November 2025 / Accepted: 7 November 2025 / Published: 21 November 2025

(This article belongs to the Section Emerging Contaminants)

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Abstract

Prolonged application and low recycling rates of agricultural plastic films have resulted in significant accumulation of microplastics (MPs) in soils, posing a threat to soil health. However, the impacts of MPs on microbial communities and enzyme activities in Mollisols remain poorly understood. To address the key question of whether soil pH drives the responses of catalase (CAT) activity and bacterial communities to MPs—a core focus of this Mollisol-based case study—we investigated the effects of different MP concentrations (1%, 5%, and 10%) on bacterial community structure and CAT activity across three Mollisol farmlands with distinct pH levels. CAT activity was stimulated at low MP concentrations but inhibited at high levels, whereas dynamic and thermodynamic parameters displayed irregular responses. Temperature sensitivity (Q₁₀) of CAT remained stable, whereas Q₁₀ of kinetic parameters varied among soils. Correlation analysis indicated that E_a and Q₁₀ in acidic soil and V_max/K_m in neutral soil and alkaline soil governed CAT activity. MPs altered α-diversity in acidic and neutral soils, changed β-diversity only in acidic soil, and promoted deterministic assembly processes. PICRUSt functional prediction suggested that functional gene shifts were most evident in acidic and neutral soils, with soil organic matter and V_max/K_m as key drivers in acidic soils and CAT in neutral soils. In contrast, responses in alkaline soil were negligible. These findings highlight soil type-specific microbial responses to MPs and their ecological risks in agricultural soils.

Keywords: microplastics; mollisols; catalase; enzymatic reaction; bacterial community

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MDPI and ACS Style

Yin, Y.; Wu, X.; Ren, Q.; Guo, Y.; Yue, Z.; Bai, X.; Xu, J.; Wang, P. Do Soil pH Levels Drive the Responses of Catalase Activity and Bacterial Communities to Microplastics? A Case Study in Mollisols. Toxics 2025, 13, 1005. https://doi.org/10.3390/toxics13121005

AMA Style

Yin Y, Wu X, Ren Q, Guo Y, Yue Z, Bai X, Xu J, Wang P. Do Soil pH Levels Drive the Responses of Catalase Activity and Bacterial Communities to Microplastics? A Case Study in Mollisols. Toxics. 2025; 13(12):1005. https://doi.org/10.3390/toxics13121005

Chicago/Turabian Style

Yin, Yuan, Xiangyu Wu, Qina Ren, Yuxin Guo, Zhonghui Yue, Xin Bai, Jia Xu, and Pengwei Wang. 2025. "Do Soil pH Levels Drive the Responses of Catalase Activity and Bacterial Communities to Microplastics? A Case Study in Mollisols" Toxics 13, no. 12: 1005. https://doi.org/10.3390/toxics13121005

APA Style

Yin, Y., Wu, X., Ren, Q., Guo, Y., Yue, Z., Bai, X., Xu, J., & Wang, P. (2025). Do Soil pH Levels Drive the Responses of Catalase Activity and Bacterial Communities to Microplastics? A Case Study in Mollisols. Toxics, 13(12), 1005. https://doi.org/10.3390/toxics13121005

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Do Soil pH Levels Drive the Responses of Catalase Activity and Bacterial Communities to Microplastics? A Case Study in Mollisols

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