WO1997038122A1 - Method for improving culture medium for recombinant yeasts - Google Patents
Method for improving culture medium for recombinant yeasts Download PDFInfo
- Publication number
- WO1997038122A1 WO1997038122A1 PCT/US1997/005799 US9705799W WO9738122A1 WO 1997038122 A1 WO1997038122 A1 WO 1997038122A1 US 9705799 W US9705799 W US 9705799W WO 9738122 A1 WO9738122 A1 WO 9738122A1
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- WO
- WIPO (PCT)
- Prior art keywords
- lactate
- yeast extract
- trehalose
- adenine
- yeast
- Prior art date
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- C—CHEMISTRY; METALLURGY
- C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
- C12N—MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA
- C12N1/00—Microorganisms, e.g. protozoa; Compositions thereof; Processes of propagating, maintaining or preserving microorganisms or compositions thereof; Processes of preparing or isolating a composition containing a microorganism; Culture media therefor
- C12N1/14—Fungi; Culture media therefor
- C12N1/16—Yeasts; Culture media therefor
- C12N1/18—Baker's yeast; Brewer's yeast
-
- C—CHEMISTRY; METALLURGY
- C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
- C12N—MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA
- C12N1/00—Microorganisms, e.g. protozoa; Compositions thereof; Processes of propagating, maintaining or preserving microorganisms or compositions thereof; Processes of preparing or isolating a composition containing a microorganism; Culture media therefor
- C12N1/14—Fungi; Culture media therefor
- C12N1/16—Yeasts; Culture media therefor
-
- C—CHEMISTRY; METALLURGY
- C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
- C12N—MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA
- C12N15/00—Mutation or genetic engineering; DNA or RNA concerning genetic engineering, vectors, e.g. plasmids, or their isolation, preparation or purification; Use of hosts therefor
- C12N15/09—Recombinant DNA-technology
- C12N15/63—Introduction of foreign genetic material using vectors; Vectors; Use of hosts therefor; Regulation of expression
- C12N15/79—Vectors or expression systems specially adapted for eukaryotic hosts
- C12N15/80—Vectors or expression systems specially adapted for eukaryotic hosts for fungi
- C12N15/81—Vectors or expression systems specially adapted for eukaryotic hosts for fungi for yeasts
Definitions
- HBsAg hepatitis B surface antigen
- Recombinant HBsAg is produced by cultivation of yeast cells in complex or chemically-defined (synthetic) culture media.
- complex media contain crude sources of nitrogen such as yeast extract and peptones.
- yeast extract and peptones Although high yields of cells and crude HBsAg are achieved in these complex culture media, overall performance is frequently variable, and sometimes unacceptably inconsistent. Inconsistencies in fermentation performance adversely affect downstream purification steps and may also increase costs for the purified product.
- Regulated expression systems are commonly used for the production of recombinant proteins.
- One type of regulated system provides tight nutritional control of the production of heterologous protein. This type of system maximizes biomass production and product stability while minimizing the adverse effects of heterologous protein expression on the host cell, e.g., Zabriskie et ai, Enzyme Microbial Technol. 8:706-717 ( 1986).
- a recombinant S. cerevisiae strain for the production of Recombivax HB® (a trademark of Merck & Co. Inc.), which strain harbors a plasmid composed of the coding sequence for HBsAg linked to the glyceraldehyde-3 -phosphate dehydrogenase (GAP) promoter, as well as an origin of replication from the yeast 2 ⁇ plasmid, and the LEU2 gene for selection in yeast cells.
- GAP glyceraldehyde-3 -phosphate dehydrogenase
- the strain is an adenine auxotroph, i.e., requires adenine for growth.
- adenine auxotrophs of yeast are typically used as recombinant hosts for heterologous protein expression, for example strains bearing mutations at the ADE 1 or ADE 2 loci. See, e.g., Kniskern, P. et al. in Expression Systems for Processes for Recombinant DNA Products (Hatch et al., eds.) ACS Symposium Series No.447 (ch.6) pp.65-75 ( 1991), and Schultz, L. et al. Gene 6 _, 123 ( 1987).
- Yeast extracts are commonly used in the media for yeast fermentations as the source for vitamins, trace elements and nitrogen nutrient. In many fermentation processes the nutrient which becomes limiting during the course of fermentation is the carbon source.
- the lot- to-lot variation of yeast extract due to variations in vendor's manufacturing processes dramatically affect recombinant yeast fermentation productivity and consistency, e.g. Recombivax HB® (a trademark of Merck & Co., Inc.) fermentation.
- the problem was partially solved in the past by the "brute-force" fermentation screening ("use-test") of new yeast extract lots. As a result, additional manpower and facilities had to be tied up, and sometimes "good” lots could not be secured due to delay in decision while other times "poor” lots were purchased and had to be thrown away.
- This disadvantage can be overcome by first identifying the critical and varying components in yeast extract that affect Recombivax HB® fermentation, and establishing rapid assay methods for these components. After a sufficiently representative database is built, the analytical results can be used to evaluate whether a particular yeast extract lot is desirable for Recombivax HB® fermentation.
- the invention relates to a method to rapidly determine whether a yeast extract lot will be "good” for recombinant yeast fermentations, including that which produces HBsAg (Recombivax
- HB® HB®
- critical varying components such as adenine, trehalose and lactic acid.
- This simple and rapid screening procedure eliminates lots with sub-optimal levels of these components and allows in most cases (about 80% of lots) superior and consistent fermentation productivity.
- the method also enables the improvement of fermentation yield by rational supplementation of those components to "poor" yeast extract lots.
- adenine and two metabolizable carbon sources are critical components in yeast extract causing fermentation inconsistency.
- Adenine is required for growth while the slowly metabolized trehalose supplies energy after growth phase for recombinant gene expression in the synthesis of expression product.
- the rapidly utilized lactate exerts a positive effect indirectly by sparing more ethanol as the carbon source for product synthesis. These effects on growth and production are mutually- dependent.
- a relatively high level of carbon sources (trehalose plus lactate, > 4 g/42 g) and a mid level of adenine (0.06 ⁇ 0.1 g/42 g) are necessary characteristics of a good yeast extract lot for yeast cultivation and crude HBsAg production.
- a method for improving the culture medium useful for the cultivation of recombinant yeasts and the production of recombinant proteins is provided.
- the medium is particularly useful for the cultivation of recombinant strains of Saccharomyces cerevisiae which produce HBsAg.
- the present invention is related to a general fermentation process for the production of recombinant proteins by yeast cells.
- the process of the present invention is demonstrated with the production of HBsAg by batch fermentation of strains of Saccharomyces cerevisiae transformed with a plasmid comprising the gene for HBsAg.
- the process of the present invention has a more general application to cultivation of other strains of S. cerevisiae and the production of other recombinant products and is not limited to HBsAg.
- yeast batch fermentation in complex medium is either a growth-limited process or a carbon source-limited process, depending on the adenine and trehalose lactate contents of the YE (yeast extract) lot used.
- concentration of these critical components in YE can vary dramatically due to variations in vendors' manufacturing processes. These inconsistencies contribute to fluctuations in fermentation performance, e.g., the amount of HBsAg produced.
- the analytical tools for adenine, trehalose and lactate in YE have been developed. Adenine content determines biomass production while carbon source (trehalose plus lactate) content affects antigen (HBsAg) product synthesis, and these two effects are related to each other.
- a mid-level adenine (0.06 ⁇ 0.1 g/42 g YE) and a high level trehalose plus lactate (> 4 g/42 g YE) are the necessary requirements for a good lot, provided that the concentration of lactate does not exceed about 4.0 g/42 g YE. Concentrations of lactate exceeding about 4.0 g/42 g YE will cause significant change in fermentation pH profile. Many poor lots are improved by rational supplementation of adenine or trehalose or lactate or their combination.
- a method for improving culture medium with limiting carbon source for a recombinant yeast prototroph comprising the steps of: a) providing a quantity of a given lot of yeast extract to be tested; b) measuring the concentrations of trehalose and lactate; c) adjusting the concentration of trehalose plus lactate to more than or equal to about 4.0 g/42g of yeast extract, provided that the concentration of lactate is less than or equal to about 4.0 g/42 g yeast extract.
- a method for improving culture medium with limiting carbon source for a recombinant yeast prototroph comprising the steps of: a) providing a quantity of a given lot of yeast extract to be tested; b) measuring the concentrations of trehalose and lactate; c) adjusting the concentration of trehalose plus lactate to between about 5.0 g/42 g of yeast extract and about 8.0 g/42 g of yeast extract, provided that the concentration of lactate is less than or equal to about 4.0 g/42 g yeast extract.
- This invention also provides a method of identifying bad lots of yeast extract for fermentation with limiting carbon source for a recombinant yeast prototroph, comprising the steps of a) providing a quantity of a given lot of yeast extract to be tested; b) measuring the concentrations of trehalose and lactate; and c) identifying bad lots as those lots with sub- optimal concentrations of trehalose or lactate.
- a method for improving culture medium with limiting carbon source for recombinant yeast adenine auxotrophs comprising the steps of: a) providing a quantity of a given lot of yeast extract to be tested; b) measuring the concentration of one or more of adenine, trehalose and lactate; c) adjusting the concentrations of adenine to between about 0.06 to about 0.10 g/42g of yeast extract, and of trehalose plus lactate to more than or equal to about 4.0 g/42g of yeast extract, provided that the concentration of lactate is less than or equal to about 4.0 g/42 g yeast extract.
- a method for improving culture medium with limiting carbon source for recombinant yeast adenine auxotrophs comprising the steps of: a) providing a quantity of a given lot of yeast extract to be tested; b) measuring the concentration of one or more of adenine, trehalose and lactate; c) adjusting the concentrations of adenine to between about 0.06 to about 0.10 g/42g of yeast extract, and of trehalose plus lactate to between about 5.0 g/42 g of yeast extract and about 8.0 g/42 g of yeast extract, provided that the concentration of lactate is less than or equal to about 4.0 g/42 g yeast extract.
- Another embodiment of this invention provides a method of identifying bad lots of yeast extract for recombinant yeast adenine auxotroph fermentation with limiting carbon source, comprising the steps of a) providing a quantity of a given lot of yeast extract to be tested; b) measuring the concentration of one or more of adenine, trehalose and lactate; and c) identifying bad lots as those lots with sub- optimal concentrations of adenine, trehalose or lactate, or combination thereof.
- Another embodiment of this invention is a method for improving culture medium with limiting carbon source for recombinant yeast adenine auxotrophs for the synthesis of recombinant Hepatitis B surface antigen, comprising the steps of: a) providing a quantity of a given lot of yeast extract to be tested; b) measuring the concentration of one or more of adenine, trehalose and lactate; c) adjusting the concentrations of adenine to between about 0.06 to about 0.1 g/42g of yeast extract, and of trehalose plus lactate to more than or equal to about 4.0 g/42g of yeast extract, provided that the concentration of lactate is less than or equal to about 4.0 g/42 g yeast extract.
- Another embodiment of this invention is a method for improving culture medium with limiting carbon source for recombinant yeast adenine auxotrophs for the synthesis of recombinant Hepatitis B surface antigen, comprising the steps of: a) providing a quantity of a given lot of yeast extract to be tested; b) measuring the concentration of one or more of adenine, trehalose and lactate; c) adjusting the concentrations of adenine to between about 0.06 to about 0.1 g/42g of yeast extract, and of trehalose plus lactate to between about 5.0 g/42 g of yeast extract and about 8.0 g/42 g of yeast extract, provided that the concentration of lactate is less than or equal to about 4.0 g/42 g yeast extract.
- Another embodiment of this invention is a method of identifying bad lots of yeast extract for recombinant yeast adenine auxotroph fermentation with limiting carbon source in the synthesis of recombinant Hepatitis B surface antigen, comprising the steps of a) providing a quantity of a given lot of yeast extract to be tested; b) measuring the concentration of adenine, trehalose and lactate; and c) identifying bad lots as those lots with suboptimal concentrations of adenine, trehalose or lactate, or combination thereof.
- yeast adenine auxotrophs are provided as illustrations of the techniques of identifying bad lots and rational supplementation of yeast extracts.
- Other yeast auxotrophs, as well as yeast prototrophs provide suitable sources for yeast extract analytical screening and supplementation for the purpose of synthesizing recombinant proteins.
- one preferred sum of the trehalose plus lactate content is more than or equal to about 4.0 g/42 g YE, provided that the concentration of lactate does not exceed about 4.0 g/42 g YE.
- This upper limit in lactate concentration avoids suboptimal yields from high fermentation pH.
- the concentration of trehalose is in principle unlimited, but at levels above about 8.0 g trehalose/ 42 g YE, it is typically not metabolized. At higher concentrations, no toxicity effect of trehalose has been observed. It is preferable to have at least both trehalose and lactate in the medium since they are providing an additional carbon source at different stages of fermentation. There are 42g yeast extract (YE) per liter of the medium.
- Trehalose -D-glucopyranosyl -D-glucopyanoside
- HPLC HPLC
- the lactate component since baker's yeast does not accumulate this metabolite, the minor amount detected (mostly ⁇ 3 g/42 g YE) is often present due to lactobacillus contamination during the vendors' manufacturing processes, a common phenomenon in the baker's yeast industry.
- trehalose One known function of trehalose is the protection of microbial membrane integrity against environmental stresses because of its unique characteristics in forming bonds with phosphodiester linkages in phospholipids. In the yeast fermentation, however, the positive effect of trehalose was often observed when trehalose was not intact, i.e., when it was split into glucose and catabolized. It appeared that trehalose affected yeast fermentation through slowly supplying glucose for growth and product synthesis.
- the culture source for all the experiments was frozen seed stocks, generated from frozen vials oi Saccharamyc.es cerevisiae 2150- 2-3 (pHBS56-GAP347/33).
- the medium for all seed stages was 5x Leu- containing 90 g/L dextrose.
- the production fermentation medium was Enhanced YEHD, comprised of 42 g/L yeast extract (YE), 35 g/L Hy-Soy peptone and 17 g/L dextrose (sterilized separately), with the presterilization pH adjusted to 5.0.
- Polyalkylene glycol was added as antifoam at 0.5 ml/L for shake-flask fermentation and 1 ml/L for stirred-tank fermentation.
- Adenine, lactate or trehalose was added prior to sterilization, at the concentrations specified.
- a frozen cell suspension (1.5 ml) was thawed at room temperature and inoculated to a 250-mL Erlenmeyer flask containing 50 ml of medium. After 24-h incubation on a rotary shaker (220 ⁇ m. 28°C), twenty ml of the culture were transferred to a 2-L Erlenmeyer flask containing 500 ml of medium, and cultivated for 24 h on a rotary shaker at 180 rpm and 28°C. The culture was used as the inoculum for fermentation studies in the 2-L shake-flasks and in some 23-L tanks. For other 23-L scale fermentations, a third seed stage was included which was developed for 24 h in a 23-L tank containing 15 liters of medium, at 28°C with an agitation of 600 m and aeration of 6 L/min.
- the 2-L baffled flask containing 200 ml of Enhanced YEHD medium was used.
- the flasks were inoculated with 4% (v/v) seed culture and incubated at 28°C and 180 ⁇ m on a rotary shaker for two days.
- an inoculum of 5% from the shake- flask seed or 8% from the third stage seed was used.
- the tanks were operated at 28°C with an agitation of 600 ⁇ m, an aeration of 12 L/min, and a back pressure of 0.6 bar.
- Respiratory activities Oxygen Uptake Rate or OUR, and C ⁇ 2 Evolution Rate or CER
- dissolved oxygen and pH were monitored on-line, while carbohydrates were monitored off ⁇ line by HPLC.
- the data was based on the assays carried out at the same time and under the same conditions for the experimentals and the respective controls to minimize variations from assay kits, standards, and assay conditions. Similarly, all the comparisons were based on the same experiment to eliminate differences due to culture conditions. When two or more measurements were carried out, average results were used.
- Adenine content in various YE lots was determined by an enzymatic assay developed based on Naher (Methods of Enzymatic
- Adenine concentration in a YE lot (g/42 g YE) is estimated from its E value based on a standard curve generated from the authentic adenine samples (0, 0.025, 0.05, 0.10, 0.20, 0.40 g/L, treated the same 8
- Trehalose and lactate contents in various yeast extract (YE) lots were determined by HPLC method using an ion-exchange column. The procedure is as follows:
- the equipment includes a solvent delivery pump, an automatic sampler injector and a detector.
- a 20- ⁇ l sample is injected into column containing a polystyrene divinylbenzene cation exchange resin (for organic acids and alcohols) maintained at 60°C.
- the sample is eluted isocratically with 0.005 M sulfuric acid at 0.7 ml/min, and monitored for refractive index (RI) change. Sample peaks are identified and quantified by comparing with those of authentic compounds. Under these conditions, trehalose eluted at -7.3 min and lactate at - 12.6 min.
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Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP9536445A JP2000508175A (en) | 1996-04-10 | 1997-04-07 | Method for improving a medium for a recombinant yeast |
EP97920222A EP0896628A1 (en) | 1996-04-10 | 1997-04-07 | Method for improving culture medium for recombinant yeasts |
AU24469/97A AU2446997A (en) | 1996-04-10 | 1997-04-07 | Method for improving culture medium for recombinant yeasts |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
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US1525096P | 1996-04-10 | 1996-04-10 | |
US60/015,250 | 1996-04-10 | ||
GB9609275.4 | 1996-05-03 | ||
GBGB9609275.4A GB9609275D0 (en) | 1996-05-03 | 1996-05-03 | Method for improving culture yeasts |
Publications (1)
Publication Number | Publication Date |
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WO1997038122A1 true WO1997038122A1 (en) | 1997-10-16 |
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Application Number | Title | Priority Date | Filing Date |
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PCT/US1997/005799 WO1997038122A1 (en) | 1996-04-10 | 1997-04-07 | Method for improving culture medium for recombinant yeasts |
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EP (1) | EP0896628A1 (en) |
JP (1) | JP2000508175A (en) |
AU (1) | AU2446997A (en) |
CA (1) | CA2251014A1 (en) |
WO (1) | WO1997038122A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10420822B2 (en) | 2011-06-13 | 2019-09-24 | Ziolase, Llc | Compositions and methods to prevent and treat biofilms |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
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US20120315260A1 (en) * | 2011-06-13 | 2012-12-13 | Svetlana A. Ivanova | Compositions and Methods to Prevent and Treat Biofilms |
JP6994821B2 (en) * | 2016-08-02 | 2022-01-14 | 三菱商事ライフサイエンス株式会社 | Reduction of ethanol production in continuous culture of Saccharomyces cerevisiae |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4863864A (en) * | 1984-12-15 | 1989-09-05 | Suntory Limited | Glucoamylase gene of rhizopus oryzae |
-
1997
- 1997-04-07 WO PCT/US1997/005799 patent/WO1997038122A1/en not_active Application Discontinuation
- 1997-04-07 EP EP97920222A patent/EP0896628A1/en not_active Withdrawn
- 1997-04-07 AU AU24469/97A patent/AU2446997A/en not_active Abandoned
- 1997-04-07 JP JP9536445A patent/JP2000508175A/en active Pending
- 1997-04-07 CA CA 2251014 patent/CA2251014A1/en not_active Abandoned
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4863864A (en) * | 1984-12-15 | 1989-09-05 | Suntory Limited | Glucoamylase gene of rhizopus oryzae |
Non-Patent Citations (4)
Title |
---|
BIOTECHNOLOGY LETTERS, March 1992, Vol. 14, No. 3, FARRIS et al., "A Genetically Improved Wine Yeast", pages 219-222. * |
EUR. J. BIOCHEM., 1992, Vol. 210, HOTTIGER et al., "The 70-Kilodalton Heat-Shock Proteins of the SSA Subfamily Negatively Modulate Heat-Shock-Induced Accumulation of Trehalose and Promote Recovery from Heat Stress in the Yeast Saccharomyces Cerevisiae", pages 125-132. * |
JOURNAL OF GENERAL MICROBIOLOGY, 1988, Vol. 134, MacKENZIE et al., "Water Stress Plating Hypersensitivity of Yeasts: Protective Role of Trehalose in Saccharomyces Cerevisiae", pages 1661-1666. * |
THE JOURNAL OF BIOLOGICAL CHEMISTRY, 28 October 1994, Vol. 269, No. 43, DEY et al., "The Glycosolation of Phosphoglucomutase is Modulated by Carbon Source and Heat Shock in Saccharomyces Cerevisiae", pages 27143-27148. * |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10420822B2 (en) | 2011-06-13 | 2019-09-24 | Ziolase, Llc | Compositions and methods to prevent and treat biofilms |
US10758596B2 (en) | 2011-06-13 | 2020-09-01 | Ziolase, Llc | Compositions and methods to prevent and treat biofilms |
Also Published As
Publication number | Publication date |
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CA2251014A1 (en) | 1997-10-16 |
AU2446997A (en) | 1997-10-29 |
EP0896628A1 (en) | 1999-02-17 |
JP2000508175A (en) | 2000-07-04 |
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