Study on the performance of Anerinibacillus sp. in degrading cyanide wastewater and its metabolic mechanism.

Cyanide extraction dominates the gold smelting industry, which leads to the generation of large amounts of cyanide-containing wastewater. In this study, Aneurinibacillus tyrosinisolvens strain named JK-1 was used for cyanide wastewater biodegradation. First, we tested the performance of JK-1 in degrading cyanide under different conditions. Then, we screened metabolic compounds and pathways associated with cyanide degradation by JK-1. Finally, we explored the potential JK-1-mediated cyanide degradation pathway. Our results showed that the optimal pH and temperature for cyanide biodegradation were 7.0 and 30 °C, respectively; under these conditions, a degradation rate of >98% was achieved within 48 h. Untargeted metabolomics results showed that increased cyanide concentration decreased the abundance of metabolic compounds by 71.1% but upregulated 32 metabolic pathways. The Kyoto Encyclopedia of Genes and Genomes enrichment results revealed significant changes in amino acid metabolism pathways during cyanide degradation by JK-1, including cyanoamino acid metabolism, β-alanine metabolism, and glutamate metabolism. Differential metabolic compounds included acetyl-CoA, l-asparagine, l-glutamic acid, l-phenylalanine, and l-glutamine. These results confirmed that cyanide degradation by JK-1 occurs through amino acid assimilation. This study provides new insights into the mechanism of cyanide biodegradation, which can be applied in the treatment of cyanide wastewater or tailings.