[Overproduction of glucoamylase by recombinant Aspergillus niger harboring multiple copies of glaA].
The glucoamylase gene (glaA) of Aspergillus niger CICIM F0410 was cloned, sequenced and expressed. The integrated plasmid pBC-Hygro-glaA carrying the glaA was constructed and transformed into A. niger F0410. Transformants with multiple copies of glaA integrated in the chromosome were selected by 150 microg/mL hygromycin B and identified by real-time PCR. Two to three multiples of glaA in the chromosome were found to be optimal for higher expression of glucoamylase. Shake-flask fermentation under optimal conditions showed that glucoamylase secreted by the transformant GB0506 was 17.5% higher than parental strain F0410 at the end of fermentation. In conclusion, increasing copy number of glaA by chromosomal integration significantly improves the yield of glucoamylase in the industrial strain of A. niger.
Yao
Ting-Ting
TT
The Key Laboratory of Industrial Biotechnology, Ministry of Education and School of Biotechnology, Southern Yangtze University, Wuxi 214036, China.
Wang
Yan-Min
YM
Gu
Jian-Long
JL
Wang
Zheng-Xiang
ZX
D001234:Aspergillus niger / Q000235:genetics*; D003001:Cloning, Molecular; D005087:Glucan 1,4-alpha-Glucosidase / Q000096:biosynthesis / Q000235:genetics*; D010957:Plasmids; D011994:Recombinant Proteins / Q000096:biosynthesis*
D011994:Recombinant Proteins; D005087:Glucan 1,4-alpha-Glucosidase