Yk. Yang et al., OPTIMUM AUTOREGULATOR ADDITION STRATEGY FOR MAXIMUM VIRGINIAMYCIN PRODUCTION IN BATCH CULTURE OF STREPTOMYCES-VIRGINIAE, Biotechnology and bioengineering, 46(5), 1995, pp. 437-442
Virginiae butanolides (VBs) are autoregulators of Streptomyces virgini
ae, which induce virginiamycin biosynthesis. Generally, autoregulators
are synthesized by the microorganism itself during culture. Addition
of chemically synthesized virginiae butanolide-C (VB-C), which is one
of the VBs, can also control the induction time and the amount of virg
iniamycin production. The optimum concentration and shot-feeding time
of VB-C for the maximum production of virginiamycins M and S were inve
stigated in flasks and jar-fermenter batch cultures. VB-C addition lat
er than 8 h from the start of culture induced not only virginiamycin M
and S synthesis but also VB synthesis. Virginiamycin M and S producti
on increased with the decrease of total VBs (produced VBs and added VB
-C) concentration. That is, although VBs are needed to induce virginia
mycin M and S synthesis, the amount of VB-C added should be such that
as small an amount as possible of VBs is synthesized to achieve the ma
ximum production of virginiamycins M and S. However, the VB-C addition
earlier than 8 h from the start of culture showed no clear relationsh
ip between the amounts of VBs and virginiamycins M and S produced. In
conclusion, the maximum production of virginiamycins M and S was attai
ned by the shot addition of 5 mu g/L VB-C at 8 h from the start of cul
ture. The maximum value was about twofold that without VB-C addition.
The optimum addition strategy of VB-C was confirmed by the jar-ferment
er experiments. (C) 1995 John Wiley & Sons, Inc.