Involved in de novo bacterial ceramide synthesis (PubMed:33063925, PubMed:34969973). Catalyzes the condensation of L-serine with palmitoyl-CoA (hexadecanoyl-CoA) to produce 3-oxosphinganine (PubMed:34969973). Can also condense serine and C16:1-CoA, but shows a preference for palmitoyl-CoA (PubMed:34969973). H(+) + hexadecanoyl-CoA + L-serine = 3-oxosphinganine + CO2 + CoA Lipid metabolism; sphingolipid metabolism. Survival of the spt-deficient mutant is much reduced, in comparison with wild type, during stationary phase of growth, especially at elevated temperatures (PubMed:33063925). Mutants are resistant towards the antibiotic polymyxin B (PubMed:33063925). Mutation causes hypersensitivity to antibiotics which affect disparate processes in different cellular compartments (PubMed:33063925). The bacterial ceramide synthesis pathway operates in a different order from that in eukaryotes. Furthermore, phylogenetic analyses support the hypothesis that the bacterial and eukaryotic ceramide pathways evolved independently. Belongs to the class-II pyridoxal-phosphate-dependent aminotransferase family.