Mutant selection of Hahella chejuensis KCTC 2396 and statistical optimization of medium components for prodigiosin yield-up

Abstract

Prodigiosin is a natural red pigment with algicidal activity against Cochlodinium polykrikoides, a major harmful red-tide microalga. To increase the yield of prodigiosin, a mutant of Hahella chejuenesis KCTC 2396, assigned M3349, was developed by an antibiotic mutagenesis using chloramphenicol. When cultured in Sucrose-based Marine Broth medium (SMB), M3349 could produce prodigiosin at 1.628±0.06 g/L, while wild type producing at 0.658±0.12 g/L under the same conditions. To increase the yield of prodigiosin production by M3349, significant medium components were determined using a two-level Plackett-Burman statistical design technique. Among fourteen components included in SMB medium, NaCl, Na₂SiO₃, MgCl₂, H₃BO₃, Na₂HPO₄, Na₂SO₄, and CaCl₂ were determined to be important for prodigiosin production. The medium formulation was finally optimized using a Box-Behnken design as follows: sucrose 10.0, peptone 8.0, yeast extract 2.0, NaCl 10.0, Na₂SO₄ 12.0, CaCl₂ 1.8, MgCl₂ 0.7 g/L; and H₃BO₃ 22.0, Na₂HPO₄ 20.0, Na₂SiO₃ 8.0 mg/L. The predicted maximum yield of prodigiosin in the optimized medium was 2.43 g/L by the Box-Behnken design, while the practical production was 2.60±0.176 g/L, which was 3.9 times higher than wild type with SMB Medium (0.658 g/L).