Effect of microbial source cultivation methods on sulfate-containing wastewater treatment performance in microbial...

Microbial electrolysis cells (MECs) have advantages in treating sulfate-containing wastewater, but challenges such as prolonged reactor start-up cycles have limited their development. By comparing the effects of different microbial sources on MEC performance, we found that inoculating the biocathode with enriched bacterial solutions significantly shortened the start-up time (15-20 d), while achieving the highest sulfate reduction efficiency of 70.2 ± 2.3%. Electrochemical analysis indicated that the integrated area of the cyclic voltammetry curve in this group was 1.0-1.2 times higher than in the other groups, and a significant increase in extracellular polymer secretion was observed. Microbial community showed that norank_f_Synergistaceae was dominant (21.9%). Functional gene prediction analyses further support the relative predominance of genes associated with biofilm formation and dissimilatory sulfate reduction. These findings indicate that highly active enriched bacteria can significantly enhance the sulfate wastewater treatment efficiency of MECs by strengthening biofilm formation mechanisms.