Two-stage cultivation of Pseudomonas sp. F12 for the production of enzymes converting DL-2-amino-Δ²-thiazoline-4-carboxylic acid to L-cysteine.
Pseudomonas sp. F12 isolated from soil could transform DL-2-amino-Δ(2)-thiazoline-4-carboxylic acid (DL-ATC) to L-cysteine. It could grow in minimal medium containing DL-ATC as the sole carbon and nitrogen source, and the apparent activity of L-cysteine synthesis (CS) achieved 122 U/mL in a 5-L bioreactor. Pseudomonas sp. F12 could utilize glucose as carbon source and ammonia as nitrogen source for growth, but no CS activity was formed. To reduce the cost of DL-ATC, the cultivation process was divided into a growth stage on glucose and ammonia and a production stage induced by DL-ATC. The excessive glucose led to the production of byproduct(s) which seriously inhibited cell growth and CS production. Ammonium was accumulated when DL-ATC was consumed, and ammonium did not inhibit CS activity formation until 60 mM. Based on the above features, fed-batch cultivation of the growth stage was developed by supplying glucose restrictively. The volumetric CS activity was enhanced more than two times that obtained under the initial conditions.
State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.
Cuili
C
Fan
Zhimin
Z
Li
Qin
Q
Ye
D061249:Batch Cell Culture Techniques / Q000379:methods*; D001711:Biotransformation; D002264:Carboxylic Acids / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry; D003545:Cysteine / Q000378:metabolism*; D003547:Cysteine Synthase / Q000096:biosynthesis* / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D011549:Pseudomonas / Q000166:cytology / Q000201:enzymology* / Q000254:growth & development* / Q000378:metabolism; D000644:Quaternary Ammonium Compounds / Q000378:metabolism; D013844:Thiazoles / Q000378:metabolism*
D002264:Carboxylic Acids; D003470:Culture Media; D000644:Quaternary Ammonium Compounds; D013844:Thiazoles; C015674:2-amino-delta(2)-thiazoline-4-carboxylic acid; D003547:Cysteine Synthase; D005947:Glucose; D003545:Cysteine