Generation of citric acid-hyperproducers independent of methanol effect by high-level expression of cexA encoding citrate exporter in Aspergillus tubingensis.
Biosci Biotechnol Biochem
; 88(10): 1203-1211, 2024 Sep 20.
Article
in En
| MEDLINE
| ID: mdl-39089868
ABSTRACT
Methanol reportedly stimulates citric acid (CA) production by Aspergillus niger and A. tubingensis; however, the underlying mechanisms remain unclear. Here, we elucidated the molecular functions of the citrate exporter gene cexA in relation to CA production by A. tubingensis WU-2223L. Methanol addition to the medium containing glucose as a carbon source markedly increased CA production by strain WU-2223L by 3.38-fold, resulting in a maximum yield of 65.5 g/L, with enhanced cexA expression. Conversely, the cexA-complementing strain with the constitutive expression promoter Ptef1 (strain LhC-1) produced 68.3 or 66.7 g/L of CA when cultivated without or with methanol, respectively. Additionally, strain LhC-2 harboring two copies of the cexA expression cassette produced 80.7 g/L of CA without methanol addition. Overall, we showed that cexA is a target gene for methanol in CA hyperproduction by A. tubingensis WU-2223L. Based on these findings, methanol-independent CA-hyperproducing strains, LhC-1 and LhC-2, were successfully generated.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Aspergillus
/
Citric Acid
/
Methanol
Language:
En
Journal:
Biosci Biotechnol Biochem
/
Biosci. biotechnol. biochem
/
Bioscience, biotechnology, and biochemistry
Journal subject:
BIOQUIMICA
/
BIOTECNOLOGIA
Year:
2024
Document type:
Article
Affiliation country:
Japón
Country of publication:
Reino Unido