Linna Du,Huan Wu,Gang Li,Yi Wei,Fei Wang,Ligen Xu,Xinjiao Dong
Microbial degradation of dyes is fundamental and essential for understanding their environmental fate . In this study, a new bacterial strain with efficient degrading capability of triphenylmethane (TPM) dyes named WKD was isolated and identified as the genus Serratia sp. by 16S rDNA analysis . The decolorization of TPM dyes by the strain especially under extreme environmental conditions were studied. The results showed that the strain could completely decolorize Malachite Green (MG) and Crystal Violet (CV) at pH values ranging from 3.0 to 10.0 and at temperatures ranging from 20 °C to 45 °C in a 12 h of incubation. The strain still showed an excellent decolorizing capability even at low (5 °C) and high (60 °C) temperatures. Moreover, the enzymatic analysis indicated that MnP, NADH-DCIP reductase, MG reductase, and CV reductase might be involved in TPM dyes biodegradation. Besides, the biodegradation pathways were proposed based on UV–visible, FTIR , and LC-Q-TOF-MS analyses. Results indicated that degradation of MG by the strain was mainly regulated by N-demethylation and hydroxylation pathways, while degradation of CV was only by the N-demethylation pathway. Therefore, Serratia sp. strain WKD is expected to have a broad application prospect for the bioremediation of TPM dyes, especially in extreme environments.
Linna Du,Xinjiao Dong,Huan Wu,Gang Li,Jiacheng Zhou,Yiqing Wu,Yanping Xiao,Jing Qin,Xiu Wang
The activated sludge process exhibits limited efficacy in decolorizing triphenylmethane (TPM) dyes like malachite green (MG) in textile wastewater. This study demonstrates that bioaugmentation with Serratia sp. strain WKD significantly enhances MG removal in activated sludge systems. Within 2 h, the combined system (activated sludge + strain WKD) achieved 98.5 ± 0.1 % decolorization efficiency—a 5.3-fold increase over sludge-only controls (18.5 ± 1.7 %). High-throughput sequencing revealed strain WKD's ecological dominance, reducing microbial alpha diversity (8 h) through competitive exclusion. When coupled with carboxymethyl cellulose-modified nano-zero-valent iron (CMC-nZVI), the hybrid system synergistically enriched stress-tolerant degraders ( Serratia sp. and Pseudomonas sp.), thereby accelerating decolorization. Prolonged incubation (24 h) enabled microbial diversity recovery (Shannon and Simpson indices) as detoxification alleviated environmental stress. Functional profiling identified pathway-specific modulation: critical metabolic functions (e.g., carbohydrate/amino acid metabolism) were transiently suppressed, while membrane transport activity remained intact, preserving system functionality. These findings establish strain WKD and CMC-nZVI as a synergistic bioaugmentation strategy, enabling rapid dye removal while maintaining microbial community resilience through dynamic stress-response mechanisms.
危险品化学品经营许可证（带存储）