Use of soybean oil and ammonium sulfate additions to optimize secondary metabolite production
✍ Scribed by B. Junker; Z. Mann; P. Gailliot; K. Byrne; J. Wilson
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 178 KB
- Volume
- 60
- Category
- Article
- ISSN
- 0006-3592
No coin nor oath required. For personal study only.
✦ Synopsis
A valine-overproducing mutant (MA7040, Streptomyces hygroscopicus) was found to produce 1.5 to 2.0 g/L of the immunoregulant, L-683,590, at the 0.6 m 3 fermentation scale in a simple batch process using soybean oil and ammonium sulfate-based GYG5 medium. Levels of both lower (L-683,795) and higher (HH1 and HH2) undesirable homolog levels were controlled adequately. This batch process was utilized to produce broth economically at the 19 m 3 fermentation scale. Material of acceptable purity was obtained without the multiple pure crystallizations previously required for an earlier culture, MA6678, requiring valine supplementation for impurity control.
Investigations at the 0.6 m 3 fermentation scale were conducted, varying agitation, pH, initial soybean oil/ ammonium sulfate charges, and initial aeration rate to further improve growth and productivity. Mid-cycle ammonia levels and lipase activity appeared to have an important role. Using mid-cycle soybean oil additions, a titer of 2.3 g/L of L-683,590 was obtained, while titers reached 2.7 g/L using mid-cycle soybean oil and ammonium sulfate additions. Both higher and lower homolog levels remained acceptable during this fed-batch process. Optimal timing of mid-cycle oil and ammonium sulfate additions was considered a critical factor to further titer improvements.