Figure 3.
Second generation ΔtnmH mutant strain S. sp. SB20024 provides a reliable supply of TNM C (11). HPLC analysis of (A) the original ΔtnmH mutant strain S. sp. SB20002 producing both TNM F (10) and TNM C (11) (at a combined isolated yield of ~0.4 mg/L) co-produced with the tiancilactones and (B) the second generation ΔtnmH mutant strain S. sp. SB20024 producing TNM C (11) as the sole metabolite (at a titer of ~4 mg/L) free from the tiancilactones. While UV–vis at 254 nm detects both the TNMs and tiancilactones, UV–vis at 539 nm detects the TNMs only. TNM F (10) (●); TNM C (11) (◆); tiancilactone A (▽); tiancilactone B (■).