Influence on dithiolopyrrolone antibiotic production by organic acids in Saccharothrix algeriensis NRRL B-24137

The influence of organic acids on growth and dithiolopyrrolone antibiotic production by Saccharothrix algeriensis NRRL B-24137 was studied. The production of dithiolopyrrolones depends upon the nature and concentration of the organic acids in the culture medium. Study of the nature of organic acids showed that the most effective organic acids for thiolutin specific production were maleic, 4-hydroxybenzoic, benzentetracarboxylic, pantothenic, pivalic and pyruvic acids (which yielded almost five-fold over the starting medium) and pimelic acid (more than three-fold). 4-Bromobenzoic acid showed the best production of senecioyl-pyrrothine (59 mg g −1 DCW). Tiglic acid showed the best production of tigloyl-pyrrothine (22 mg g −1 DCW). The highest yield of isobutyryl-pyrrothine (7.6 mg g −1 DCW) was observed in the presence of crotonic acid. Sorbic acid yielded the best production of butanoyl-pyrrothine (26 mg g −1 DCW). Methacrylic, butyric, pyruvic and 4-bromobenzoic acids also exhibited the best production of butanoyl-pyrrothine (27–11-fold). Study of organic acid concentration showed that among the selected organic acids, pimelic acid yielded the highest specific production of thiolutin (91 mg g −1 DCW) at 7.5 mM; and senecioyl-pyrrothine (11 mg g −1 DCW), tigloyl-pyrrothine (9 mg g −1 DCW) and butanoyl-pyrrothine (3.5 mg g −1 DCW) at 5 mM. Pyruvic acid at 1.25 mM enhanced the production of senecioyl-pyrrothine (4.3 mg g −1 DCW). The maximum production of tigloyl-pyrrothine (18.6 mg g −1 DCW) was observed in the presence of tiglic acid at 2.5 mM. Maximum production of isobutyryl-pyrrothine was observed in the presence of 7.5 mM tiglic acid. In addition, methacrylic acid (at 5 mM) and butyric acid (at 2.5 mM) enhanced the production of butanoyl-pyrrothine (26 and 20 times, respectively). The above results can be employed in the optimisation of the culture medium for the production of dithiolopyrrolone in higher quantities.