Claims
- 1. An E. coli strain which produces L-threonine, derived by a process comprising the steps of:
- (i) transducing E. coli strain with a first bacteriophage P1 bearing genetic material necessary for saccharose assimilation, and
- (ii) isolating a transductant capable of utilizing saccharose or a saccharose-bearing substrate as a source of carbon.
- 2. The E. coli strain of claim 1, further derived by a process comprising the steps of:
- (iii) transducing said transductant with a second bacteriophage P1, and
- (iv) isolating a transductant lacking threonine dehydrogenase activity.
- 3. The E. coli of claim 2, wherein said second bacteriophage P1 bears a mutant threonine dehydrogenase-encoding gene whose gene product is devoid of threonine dehydrogenase activity.
- 4. The E. coli of claim 2, wherein said second bacteriophage P1 was obtained by growning bacteriophage P1 on a mutant E. coli strain devoid of threonine dehydrogenase activity and bearing a mutation in the threonine dehydrogenase-encoding gene.
- 5. A method for deriving an E. coli strain which produces L-threonine, said method comprising the steps of:
- (i) transducing E. coli strain with a first bacteriophage P1 bearing genetic material necessary for saccharose assimilation, and
- (ii) isolating a transductant capable of utilizing saccharose or a saccharose-bearing substrate as a source of carbon.
- 6. The method of claim 5, further comprising the steps of:
- (iii) transducing said transductant with a second bacteriophage P1, and
- (iv) isolating a transductant lacking threonine dehydrogenase activity.
- 7. The method of claim 6, wherein said second bacteriophage P1 bears a mutant threonine dehydrogenase-encoding gene whose gene product is devoid of threonine dehydrogenase activity.
- 8. The method of claim 6, wherein said second bacteriophage P1 was obtained by growning bacteriophage P1 on a mutant E. coli strain devoid of threonine dehydrogenase activity and bearing a mutation in the threonine dehydrogenase encoding gene.
- 9. A method for producing L-threonine, comprising using an E. coli strain derived by a method comprising the steps of:
- (i) transducing E. coli strain with a first bacteriophage P1 bearing genetic material necessary for saccharose assimilation, and
- (ii) isolating a transductant capable of utilizing saccharose or a saccharose-bearing substrate as a source of carbon.
- 10. The method of claim 9, said derivation further comprising the steps of:
- (iii) transducing said transductant with a second bacteriophage P1, and
- (iv) isolating a transductant lacking threonine dehydrogenase activity.
- 11. The method of claim 10, wherein said second bacteriophage P1 bears a mutant threonine dehydrogenase-encoding gene whose gene product is devoid of threonine dehydrogenase activity.
- 12. The method of claim 10, wherein said second bacteriophage P1 was obtained by growning bacteriophage P1 on a mutant E. coli strain devoid of threonine dehydrogenase activity and bearing a mutation in the threonine dehydrogenase-encoding gene.
Priority Claims (2)
Number |
Date |
Country |
Kind |
8801386 |
Dec 1988 |
BEX |
|
88 16570 |
Dec 1988 |
FRX |
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Parent Case Info
This application is a Continuation of application Ser. No. 08/890,199 filed on Jul. 9, 1997 now U.S. Pat. No. 5,976,843, which is a continuation of application Ser. No. 08/633,028 filed on Apr. 16, 1996, now U.S. Pat. No. 5,705,371, which is a continuation of application Ser. No. 08/430,455 filed on Apr. 28, 1995, now U.S. Pat. No. 5,631,157 which is a continuation of application Ser. No. 08/336,563 filed on Nov. 9, 1994, now U.S. Pat. No. 5,538,873, which is a continuation of application Ser. No. 07/872,141 filed on Apr. 22, 1992, now abandoned, which is a divisional application Ser. No. 07/499,278 filed on Jun. 12, 1990, now U.S. Pat. No. 5,175,107, which is a 371 of PCT/SU88/00207 filed on Oct. 25, 1988.
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