Enhanced citric acid production by a yeast Yarrowia lipolytica over-expressing a pyruvate carboxylase gene.
In this study, after the expression of a pyruvate carboxylase gene (PYC) cloned from Meyerozyma guilliermondii in a marine-derived yeast Yarrowia lipolytica SWJ-1b, a transformant PG86 obtained had much higher PYC activity than Y. lipolytica SWJ-1b. At the same time, the PYC gene expression and citric acid (CA) production by the transformant PG86 were also greatly enhanced. When glucose concentration in the medium was 60.0 g L(-1), CA concentration formed by the transformant PG86 was 34.02 g L(-1), leading to a CA yield of 0.57 g g(-1) of glucose. During a 10-L fed-batch fermentation, the final concentration of CA was 101.0 ± 1.3 g L(-1), the yield was 0.89 g g(-1) of glucose, the productivity was 0.42 g L(-1) h(-1) and only 5.93 g L(-1) reducing sugar was left in the fermented medium within 240 h of the fed-batch fermentation. HPLC analysis showed that most of the fermentation products were CA.
College of Marine Life Sciences, Ocean University of China, Yushan Road, No. 5, Qingdao, China.
Mei-Juan
MJ
Tan
College of Marine Life Sciences, Ocean University of China, Yushan Road, No. 5, Qingdao, China.
Xi
X
Chen
College of Marine Life Sciences, Ocean University of China, Yushan Road, No. 5, Qingdao, China.
Yu-Kuan
YK
Wang
College of Marine Life Sciences, Ocean University of China, Yushan Road, No. 5, Qingdao, China.
Guang-Lei
GL
Liu
College of Marine Life Sciences, Ocean University of China, Yushan Road, No. 5, Qingdao, China. zhenming@sdu.edu.cn.
Zhen-Ming
ZM
Chi
D002851:Chromatography, High Pressure Liquid; D019343:Citric Acid / Q000378:metabolism*; D005285:Fermentation; D005822:Genetic Vectors; D005947:Glucose / Q000378:metabolism; D011766:Pyruvate Carboxylase / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction; D014170:Transformation, Genetic; D025062:Yarrowia / Q000235:genetics / Q000378:metabolism*
D019343:Citric Acid; D011766:Pyruvate Carboxylase; D005947:Glucose
Citric acid; Fed-batch fermentation; Gene expression; Pyruvate carboxylase; Yarrowia lipolytica