Linking proteomic function and structure to electroactive biofilms development across electrode orientations.

The functionality of electroactive biofilms (EABs) is profoundly influenced by the proteomic dynamics within microbial communities, particularly through the participation of proteins in electron transfer. This study explored the impact of electrode surface orientation, measured by varying oblique angles, on the performance of EABs in bioelectrochemical systems (BES). Utilizing quantitative proteomics, results indicated that a slightly oblique angle (45°) optimized the spatial arrangement of microbial cells, enhancing electron transport efficiency compared to other angles tested. Specifically, the 45° orientation resulted in a 2.36-fold increase in the abundance of c-type cytochromes compared to the 90°. Additionally, Geobacter, showed a relative abundance of 83.25 % at 45°, correlating with a peak current density of 1.87 ± 0.04 A/m2. These microbial and proteomic adaptations highlighted the intricate balance between microbial behavior and the physical environment, which could be tuned to optimize operations. The findings provided new insights into the design and enhancement of BES.

Cooperation triggers nitrogen removal and algal inhibition by actinomycetes during landscape water treatment: Performance and metabolic activity.

The actinomycetes strain Streptomyces sp. XD-11-9-3 and Streptomyces sp. 5 were isolated and presented poor denitrification performance. Co-culture of actinomycetes triggers nitrogen removal capacity under aerobic conditions (reduced 96% of total nitrogen). Nitrogen balance analysis presented that 71% of initial nitrogen converted as gaseous nitrogen. Moreover, co-culture increased the concentrations of adenosine triphosphate (>2.1 folds) and electron-transmission system activity (>1.5 folds) significantly. The co-culture presented excellent carbon source metabolism activity (especially amines and carboxylic acids) compared with monoculture. The removal efficiency of total nitrogen in the micro-polluted landscape water water reached 61% in the co-culture system, and the algal survival could be inhibited significantly. However, the dominant niche of the co-culture system restrained the diversity of the indigenous nirS-type denitrifying bacterial community. This study provided a novel pathway to the research of co-culture inefficiency aerobic denitrifier and further application in the restoration of polluted water.