Although remediation of toxic vanadium (V) [V(V)] pollution can be achieved through either heterotrophic or sulfur-based autotrophic microbial reduction, these processes would require a large amount of organic carbons or generate excessive sulfate. This study reported that by using mixotrophic V(V) bio-reduction with acetate and elemental sulfur [S(0)] as joint electron donors, V(V) removal performance was enhanced due to cooccurrence of heterotrophic and autotrophic activities. Deposited vanadium (IV) was identified as the main reduction product by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy. Based on 16S rRNA gene amplicon sequencing, qPCR and genus-specific reverse transcription qPCR, it was observed that V(V) was likely detoxified by heterotrophic V(V) reducers (e.g., Syntrophobacter, Spirochaeta and Geobacter). Cytochrome c, intracellular nicotinamide adenine dinucleotide and extracellular polymeric substances were involved in V(V) reduction and binding. Organic metabolites synthesized by autotrophs (e.g., Thioclava) with energy from S(0) oxidation might compensate electron donors for heterotrophic V(V) and sulfate reducers. Less sulfate was accumulated presumably due to activities of sulfur-respiring genera (e.g., Desulfurella). This study demonstrates mixotrophic microbial V(V) reduction can save organic dosage and avoid excessive sulfate accumulation, which will be beneficial to bioremediation of V(V) contamination.

尽管可以通过异养或基于硫的自养微生物还原来修复有毒钒（V）[V（V）]污染，但这些过程将需要大量有机碳或产生过量的硫酸盐。这项研究报告说，通过使用乙酸和元素硫[S（0）]的混合营养型V（V）生物还原作为联合电子供体，由于异养和自养活动的共同发生，V（V）的去除性能得到了提高。通过扫描电子显微镜，能量分散X射线光谱，X射线衍射和X射线光电子能谱确定沉积的钒（IV）是主要的还原产物。基于16S rRNA基因扩增子测序，qPCR和属特异性逆转录qPCR，观察到V（V）可能被异养V（V）还原剂（例如幽门螺杆菌，螺旋藻和土杆菌）。细胞色素c，细胞内烟酰胺腺嘌呤二核苷酸和细胞外聚合物参与V（V）减少和绑定。由自养生物（例如，硫唑烷）与S（0）氧化能合成的有机代谢物可能会补偿异养V（V）和硫酸盐还原剂的电子供体。可能由于吸硫属（例如，Desulfurella）的活性而积累了较少的硫酸盐。这项研究表明，减少混合营养型微生物的V（V）可以节省有机剂量并避免过多的硫酸盐积累，这将有利于V（V）污染的生物修复。