The present study investigates a novel sulfate-reducing bacterium, Pseudodesulfovibrio sp. MCM B-508, isolated from produced water, for its ability to produce cerium sulfide, an industrially valuable rare earth colorant. The study demonstrates a microbial route for pigment synthesis by cloning and expressing dissimilatory sulfite reductase (dsrAB) genes from this bacterium in Escherichia coli. The enzyme dissimilatory sulfite reductase shared a maximum of 94.09% homology with published dissimilatory sulfite reductase sequences from the GenBank database, highlighting its novelty. Using molecular engineering techniques, including chaperone co-expression with the pGro7 vector, the sulfate conversion efficiency was significantly enhanced to 71.23%, overcoming limitations in sulfate-reducing bacterial processes. The research successfully converted cerium sulfate to the desired gamma-form cerium sulfide (Ce2S3) through a recombinant E. coli strain, achieving a more efficient and eco-friendly production method compared to conventional chemical synthesis approaches. X-ray diffraction analysis confirmed the formation of the targeted pigment, with major peaks at 25.3 and 32.8° 2θ, demonstrating the potential for an industrially viable, sustainable pigment production process.
Keywords: Pseudodesulfovibrio; 3D structure; Cerium sulfide; Dissimilatory sulfite reductase; Heterologous expression; Sulfate-reducing bacteria; XRD.
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