The production of dimethylsulfoniopropionate by bacteria with mmtN linked to non-ribosomal peptide synthase gene.

Dimethylsulfoniopropionate (DMSP) is a vital sulfur-containing compound with worldwide significance, serving as the primary precursor for dimethyl sulfide (DMS), a volatile sulfur compound that plays a role in atmospheric chemistry and influences the Earth's climate on a global scale. The study investigated the ability of four bacterial strains, namely Acidimangrovimonas sediminis MS2-2 (MS2-2), Hartmannibacter diazotrophicus E18 ^T (E18 ^T ), Rhizobium lusitanum 22705 (22705), and Nitrospirillum iridis DSM22198 (DSM22198), to produce and degrade DMSP. These strains were assessed for their DMSP synthesis ability with the mmtN linked to non-ribosomal peptide synthase (NRPS) gene. The results showed that MS2-2, and E18 ^T bacteria, which contained the mmtN but not linked to an NRPS gene, increased DMSP production with increasing salinity. The highest production of DMSP was achieved at 25 PSU when either methionine was added or low nitrogen conditions were present, yielding 1656.03 ± 41.04 and 265.59 ± 9.17 nmol/mg protein, respectively, and subsequently under the conditions of methionine addition or low nitrogen, both strains reached their maximum DMSP production at 25 PSU. Furthermore, the strains MS2-2, E18 ^T , and 22705 with the mmtN gene but not linked to an NRPS gene were found to be involved in DMS production. This research contributes to the understanding of the genes involved in DMSP biosynthesis in bacteria that produce DMSP.