Transcriptome analysis of Shewanella xiamenensis co-incubated with internalized carbon dots in response to boosting Cr(VI)-bioreduction

Abstract

High-conductivity nanomaterials commonly can across the membrane of Shewanella to mediate the extracellular electron transfer (EET). In this study, carbon quantum dots (CDs) was used to boost Cr(VI)-bioreduction efficiency of Shewanella xiamenensis. After an 18-hour experimental reaction, CDs-added groups were observed to significantly enhance Cr(VI)-bioreduction efficiency both in dark and light conditions, with reduction rates of 100% and 91.9%, respectively, whereas the results of CDs-free groups were found of lower removal efficiency in dark (60.6%) and light (63.2%) conditions. Observations of transcriptome analysis found that a positive role of internalized CDs in improving genes expressed level in secretion system, cytochrome c, electron transfer, antioxidant defense, energy metabolism, and purine and pyrimidine metabolism of S. xiamenensis, resulting in elevating the efficiency of EET process and activating cells. These findings provide new insights into the underlying molecular mechanisms of Cr(VI) bioreduction in Shewanella xiamenensis at the proteome level.