Catalyzes the CoA-dependent reduction of elemental sulfur (S(0)) to produce hydrogen sulfide (PubMed:17449625, PubMed:24723088). Can use both NADPH and NADH, but shows a preference for NADPH (PubMed:24723088). May enable S(0) to be used, via sulfide, for iron-sulfur cluster synthesis by SipA (Probable). Also shows coenzyme A disulfide reductase (CoADR) activity with both NADH and NADPH (PubMed:15720393, PubMed:17449625). However, CoADR specific activity is about 20-fold lower than the sulfur reduction assay and CoADR activity appears to be an artifactual side reaction and is not thought to have any physiological relevance (PubMed:17449625). Also shows NAD(P)H oxidase activity with both NADH and NADPH (PubMed:24723088). hydrogen sulfide + NADP(+) = NADPH + sulfur hydrogen sulfide + NAD(+) = NADH + sulfur 2 CoA + NADP(+) = CoA-disulfide + H(+) + NADPH 2 CoA + NAD(+) = CoA-disulfide + H(+) + NADH Binds 1 FAD per subunit. Optimum pH is 6.5 for sulfide production. Homodimer. Up-regulated up to sevenfold by elemental sulfur addition. Deletion mutant does not exhibit an obvious phenotype and produces sulfide and acetate in amounts comparable to those produced by the parent strain. Belongs to the class-III pyridine nucleotide-disulfide oxidoreductase family.