Efficient production of L-lactic acid by Crabtree-negative yeast Candida boidinii.
Industrial production of L-lactic acid, which in polymerized form as poly-lactic acid is widely used as a biodegradable plastic, has been attracting world-wide attention. By genetic engineering we constructed a strain of the Crabtree-negative yeast Candida boidinii that efficiently produced a large amount of L-lactic acid. The alcohol fermentation pathway of C. boidinii was altered by disruption of the PDC1 gene encoding pyruvate decarboxylase, resulting in an ethanol production that was reduced to 17% of the wild-type strain. The alcohol fermentation pathway of the PDC1 deletion strain was then successfully utilized for the synthesis of L-lactic acid by placing the bovine L-lactate dehydrogenase-encoding gene under the control of the PDC1 promoter by targeted integration. Optimizing the conditions for batch culture in a 5 l jar-fermenter resulted in an L-lactic acid production reaching 85.9 g/l within 48 h. This productivity (1.79 g/l/h) is the highest thus far reported for L-lactic acid-producing yeasts.
Osawa
Fumi
F
Central Laboratories for Frontier Technology, Kirin Holdings Co. Ltd, Kanagawa 236-0004, Japan.
Fujii
Toshio
T
Nishida
Takehisa
T
Tada
Nobuki
N
Ohnishi
Toru
T
Kobayashi
Osamu
O
Komeda
Toshihiro
T
Yoshida
Satoshi
S
D000595:Amino Acid Sequence; D000818:Animals; D002175:Candida / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D002417:Cattle; D003001:Cloning, Molecular; D000431:Ethanol / Q000378:metabolism; D005285:Fermentation; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D005818:Genetic Engineering; D007770:L-Lactate Dehydrogenase / Q000235:genetics / Q000378:metabolism; D019344:Lactic Acid / Q000378:metabolism*; D008969:Molecular Sequence Data; D011767:Pyruvate Decarboxylase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment
D005656:Fungal Proteins; D019344:Lactic Acid; D000431:Ethanol; D007770:L-Lactate Dehydrogenase; D011767:Pyruvate Decarboxylase