# Integrated Transcriptomic and Proteomic Analysis of the Stress Response Mechanisms of Micractinium from the Tibetan Plateau Under Leather Wastewater Exposure

## TL;DR

A microalga from the Tibetan Plateau efficiently removes pollutants from tannery wastewater, adapting through molecular mechanisms involving energy metabolism and stress response.

## Contribution

This study provides novel insights into the molecular mechanisms of microalgal adaptation to tannery wastewater using integrated transcriptomic and proteomic analyses.

## Key findings

- Strain LL-1 achieves 98.7% ammonia nitrogen removal efficiency in tannery wastewater.
- Transcriptomic and proteomic analyses reveal key pathways in cell proliferation, energy metabolism, and stress response.
- Dynamic adaptation involves signal perception, metabolic reconfiguration, and antioxidant mechanisms.

## Abstract

Microalgae demonstrate strong environmental resilience and high pollutant removal efficiency in tannery wastewater treatment. In this study, Micractinium sp. strain LL-1 was isolated from the Lalu Wetland on the Tibetan Plateau. Transcriptomic and proteomic analyses were integrated to elucidate its molecular response mechanisms to tannery wastewater stress. Results revealed that strain LL-1 exhibits robust adaptability by regulating key biological processes, including cell proliferation, morphological development, protein synthesis, and photosynthesis. Specifically, transcriptomics highlighted significant alterations in the cytoskeletal microtubule system and photosynthetic pathways, while proteomics showed that the strain enhances tolerance via the modulation of energy metabolism, antioxidant mechanisms, and pollutant efflux. These findings provide novel theoretical insights into microalgal-based wastewater treatment and offer potential strategies for resource recovery and environmental remediation.

In this study, a strain of green microalga adapted to the extreme environmental conditions of the Tibetan Plateau was isolated from the Lalu Wetland. The isolate was identified and tentatively designated as Micractinium sp. LL-1. Following the inoculation of strain LL-1 into tannery wastewater, the ammonia nitrogen concentration was rapidly reduced, achieving a removal efficiency of 98.7%. The maximum accumulated biomass reached 1641.68 mg/L and 1461.28 mg/L. Integrated transcriptomic and label-free quantitative proteomic approaches were employed to systematically investigate the molecular response mechanisms of LL-1 under tannery wastewater stress. Transcriptomic analysis revealed that differentially expressed genes were enriched in pathways related to cell proliferation, morphogenesis, intracellular transport, protein synthesis, photosynthesis, and redox processes. Proteomic analysis indicated that LL-1 enhances cellular and enzymatic activities, strengthens regulatory capacity, modulates key metabolic pathways, and upregulates stress-responsive proteins. Under tannery wastewater stress, LL-1 exhibits dynamic adaptation involving signal perception and metabolic reconfiguration through the coordinated regulation of multiple pathways. Specifically, ribosomal translation and nucleic acid binding regulate biosynthetic capacity; the redistribution of energy metabolism boosts photosynthetic carbon fixation and ATP generation; and membrane transport coupled with antioxidant mechanisms mitigates stress-induced damage. Collectively, this study provides theoretical insights into microalgal adaptation to complex wastewater environments and offers potential targets for strain improvement and wastewater valorization.