ATP-citrate lyase activity and carotenoid production in batch cultures of Phaffia rhodozyma under nitrogen-limited and nonlimited conditions.
ATP-citrate lyase (ACL) is the key cytoplasmic enzyme which supplies acetyl-CoA for fatty acids in oleaginous yeast. Although it has been suggested that fatty acid and carotenoid biosynthesis may have a common source of acetyl-CoA in Phaffia rhodozyma, the source for carotenoids is currently unknown. The purpose of this work was to analyze the development of ACL activity during batch cultures of P. rhodozyma under ammonium-limited and nonammonium-limited conditions and study its possible relationship with carotenoid synthesis. Every experiment showed carotenoid accumulation linked to an increasing ACL activity. Moreover, the ACL activity increased with dissolved oxygen (DO), i.e., ACL responded to DO in a similar way as carotenoid synthesis. Additionally, in the ammonium-limited culture, ACL activity increased upon ammonium depletion. However, the contribution to carotenoid accumulation in that case was negligible. This suggests that P. rhodozyma has developed two components of ACL, each one responsive to a different environmental stimulus, i.e., DO and ammonium depletion. The role of each component is still unknown; however, considering that the former responds to DO and the known role of carotenoids as antioxidants, it may be a provider of acetyl-CoA for carotenoid synthesis.
Chávez-Cabrera
Cipriano
C
Department of Biotechnology and Bioengineering, Cinvestav-IPN, Av. Instituto Politécnico Nacional 2508, Col. San Pedro Zacatenco, México 07360, DF, México.
Flores-Bustamante
Zoila R
ZR
Marsch
Rodolfo
R
Montes
María del Carmen
Mdel C
Sánchez
Sergio
S
Cancino-Díaz
Juan Carlos
JC
Flores-Cotera
Luis Bernardo
LB
D001275:ATP Citrate (pro-S)-Lyase / Q000096:biosynthesis*; D000105:Acetyl Coenzyme A / Q000378:metabolism; D001487:Basidiomycota / Q000254:growth & development* / Q000378:metabolism; D002338:Carotenoids / Q000096:biosynthesis*; D005656:Fungal Proteins / Q000096:biosynthesis*; D009584:Nitrogen / Q000378:metabolism*; D000644:Quaternary Ammonium Compounds / Q000378:metabolism
D005656:Fungal Proteins; D000644:Quaternary Ammonium Compounds; D002338:Carotenoids; D000105:Acetyl Coenzyme A; D001275:ATP Citrate (pro-S)-Lyase; D009584:Nitrogen