TY - JOUR
T1 - Overexpression of the gene encoding alternative oxidase for enhanced glucose consumption in oxalic acid producing Aspergillus niger expressing oxaloacetate hydrolase gene
AU - Yoshioka, Isato
AU - Kobayashi, Keiichi
AU - Kirimura, Kohtaro
PY - 2020/2
Y1 - 2020/2
N2 - The filamentous fungus Aspergillus niger is a well-known hyper-producer of organic acids such as citric acid and oxalic acid. This fungus possesses the cyanide (CN)-insensitive respiration pathway consisting of alternative oxidase (EC 1.10.3.11; AOX), in addition to the cytochrome pathway. Since this CN-insensitive respiration pathway reoxidizes NADH without ATP production, it contributes to continuous glycolysis in A. niger. In this study, to show the availability of aoxA gene encoding AOX as a tool for metabolic engineering, we generated efficient oxalic acid (OA)-producers by genetic engineering of A. niger using aoxA gene. The OA-producing strain EOAH-1, generated by overexpression of the oxaloacetate hydrolase (EC 3.7.1.1; OAH) gene oahA in A. niger WU-2223L, produced 28 g/L OA from 30 g/L glucose during the 9-day cultivation period. Moreover, the strain EAOXOAH-1, generated by overexpression of both aoxA and oahA genes in strain WU-2223L, produced 28 g/L OA during the 7-day cultivation period. Strain EAOXOAH-1 showed higher glucose consumption rate than EOAH-1 did, indicating that overexpression of aoxA contributed to the acceleration of glucose consumption, and that the OA production period was shortened by 2 days. Thus, we clearly show that AOX gene must be an effective tool in metabolic engineering for efficient organic acids production from carbohydrates.
AB - The filamentous fungus Aspergillus niger is a well-known hyper-producer of organic acids such as citric acid and oxalic acid. This fungus possesses the cyanide (CN)-insensitive respiration pathway consisting of alternative oxidase (EC 1.10.3.11; AOX), in addition to the cytochrome pathway. Since this CN-insensitive respiration pathway reoxidizes NADH without ATP production, it contributes to continuous glycolysis in A. niger. In this study, to show the availability of aoxA gene encoding AOX as a tool for metabolic engineering, we generated efficient oxalic acid (OA)-producers by genetic engineering of A. niger using aoxA gene. The OA-producing strain EOAH-1, generated by overexpression of the oxaloacetate hydrolase (EC 3.7.1.1; OAH) gene oahA in A. niger WU-2223L, produced 28 g/L OA from 30 g/L glucose during the 9-day cultivation period. Moreover, the strain EAOXOAH-1, generated by overexpression of both aoxA and oahA genes in strain WU-2223L, produced 28 g/L OA during the 7-day cultivation period. Strain EAOXOAH-1 showed higher glucose consumption rate than EOAH-1 did, indicating that overexpression of aoxA contributed to the acceleration of glucose consumption, and that the OA production period was shortened by 2 days. Thus, we clearly show that AOX gene must be an effective tool in metabolic engineering for efficient organic acids production from carbohydrates.
KW - Alternative oxidase
KW - Aspergillus niger
KW - Glycolysis
KW - Metabolic engineering
KW - Oxalic acid
UR - http://www.scopus.com/inward/record.url?scp=85073156826&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85073156826&partnerID=8YFLogxK
U2 - 10.1016/j.jbiosc.2019.08.014
DO - 10.1016/j.jbiosc.2019.08.014
M3 - Article
C2 - 31611058
AN - SCOPUS:85073156826
VL - 129
SP - 172
EP - 176
JO - Journal of Bioscience and Bioengineering
JF - Journal of Bioscience and Bioengineering
SN - 1389-1723
IS - 2
ER -