Enhancing anthraquinone dyestuff degradation with composite activator: Proteomics of Burkholderia sp. DDMZ1-1

In this study, the composite activator was introduced to enhance the biodegradation of recalcitrant anthraquinone dyestuff (reactive blue 19, RB19) by Burkholderia sp. DDMZ1-1. The strain was found to decolorize 100 mg/L RB19 maximally (78% for 48 h cultivation) at the optimal conditions: static incubation, pH 6, 37 °C and 1% NaCl concentration. Further, the upgraded composite activator comprised of epigallocatechin gallate (2.5 mg/L), theanine (2.5 mg/L) and FeCl₃ (4.5 mg/L) manifested its favorable facilitative potential. An intensified secretion and activities of extracellular ligninolytic enzymes (MnP and LiP) took place via the induction of composite activator. Also, the composite activator somewhat reduced the phytotoxicity level of RB19 degraded metabolites. Proteomic profiling revealed that multiple functional proteins including pyruvate dehydrogenase, NADH-quinone oxidoreductase, superoxide dismutase, glutathione S-transferase, peroxidase, etc., were induced to be up-regulated in carbohydrate metabolism, oxidative phosphorylation, antioxidant system, glutathione metabolism and extracellular complexation with siderophores on account of composite activator. Elevated reducing force (NADH, H⁺), extracellular peroxidases (MnP, LiP, DyP) in concert with H₂O₂, and the cellular homeostasis maintenance jointly facilitated RB19 decomposition. Collectively, this study will give insights into the underlying bioaugmentation mechanism of composite activator reinforcing the bioremediation of refractory textile wastewater by an indigenous Burkholderia strain.