Influence of fungal elicitors on biosynthesis of natamycin by Streptomyces natalensis HW-2.
To investigate the effect of fungal elicitors on biosynthesis of natamycin in the cultures of Streptomyces natalensis HW-2, the biomass and filtrate of the broth from Aspergillus niger AS 3.6472, Penicillium chrysogenum AS 3.5163, A. oryzae AS 3.2068, and Saccharomyces cerevisiae AS 2.2081 were used to induce natamycin production in S. natalensis HW-2. The results showed that the biomass of P. chrysogenum AS 3.5163 could enhance the yield of natamycin from 0.639 to 0.875 g l(-1). The elicitor from the fermentation broth of P. chrysogenum AS 3.5163 showed the highest inducing efficiency with the yield of natamycin enhanced from 0.632 to 1.84 g l(-1). The elicitor that was cultured for 2 days showed the strongest inducing activity during the fermentation of S. natalensis HW-2 for 24 h, and the yield of natamycin was enhanced from 0.637 to 2.12 g l(-1). The biochemical parameters were examined at the end of fermentation and the results demonstrated that both the growth of cells and the concentration of residual sugar could be influenced. The residual sugar decreased from 5.03 to 4.27 g l(-1), and the biomass decreased from 10.26 to 6.87 g l(-1). Finally, the elicitor was identified as a low molecular weight substance with a similar polarity to that of butyl alcohol by primary qualitative analysis.