Optimization of the medium for streptolydigin production by Streptomyces lydicus AS 4.2501 with precursor feeding using response surface methodology

Plackett-Burman multifactorial design and the consequent response surface methodology (RSM) were used to improve the streptolydigin yield in a newly isolated strain Streptomyces lydicus AS 4.2501 with a dramatic streptolydigin increase of 18.6%. Also propionate's role as a precursor for the streptolydigin biosynthesis was for the first time practically validated. The results from the Plackett-Burman design showed that starch, peptone and K(2)HPO(4) were influential factors to the biosynthesis of streptolydigin. Consequent analysis with RSM not only detected the interactions among these important factors, but also established two models referring to the streptolydigin titer and biomass, respectively. Additionally, the relationship between the production of streptolydigin and the growth of mycelia was first discussed using statistical methods, which is of great help to the overproduction of the related secondary metabolites. (C) 2010 Published by Elsevier B.V. on behalf of Taiwan Institute of Chemical Engineers.