Fig. 3

Screening of fatty acid/acyl-CoA responsive promoters. A Comparative transcriptional analysis to characterize endogenous promoters that respond to fatty acid/acyl-CoA. Wild-type strain (CEN.PK 113-11C) was cultivated in minimal medium without (black arrow), or with 0.3% (v/v) oleic acid (orange arrow), and samples were taken at 18 h, 36 h, and 48 h, respectively. FFA producing strain (YJZ121, black arrow) was cultivated in minimal medium, and samples were taken at 18 h, 36 h, and 48 h, respectively. Acyl-CoA producing strain (JV03) was cultivated in minimal medium without (black arrow), or with 0.3% (v/v) oleic acid (orange arrow). For strain JV03 without oleic acid, samples were taken at 18 h, 36 h, and 48 h, respectively. For strain JV03 with oleic acid, owing to oleic acid addition severely hindering cell growth, samples were taken at their own growth phase. B Candidate promoters were evaluated by fluorescence intensity of eGFP using exogenous FFA (0.5% oleic acid), endogenous FFA and acyl-CoA. C Promoters responsive to exogenous FFA. eGFP under the control of FFA responsive promoters was expressed in wild-type strain and cultivated in minimal media with or without 0.5% (v/v) oleic acid. D Promoters responsive to endogenous acyl-CoA. eGFP under the control of acyl-CoA responsive promoters was expressed in wild-type and acyl-CoA producing strain JV03, respectively. Data are presented as mean ± SD of three biological replicates