CN117625423A - Saccharomyces cerevisiae with improved xylose utilization efficiency, application thereof and method for producing ethanol - Google Patents
Saccharomyces cerevisiae with improved xylose utilization efficiency, application thereof and method for producing ethanol Download PDFInfo
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Classifications
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E50/00—Technologies for the production of fuel of non-fossil origin
- Y02E50/10—Biofuels, e.g. bio-diesel
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- Micro-Organisms Or Cultivation Processes Thereof (AREA)
- Preparation Of Compounds By Using Micro-Organisms (AREA)
Abstract
The invention relates to the technical field of bioengineering, and discloses saccharomyces cerevisiae with improved xylose utilization efficiency, application thereof and a method for producing ethanol. The growth capacity of xylose utilization and the xylose utilization efficiency of the saccharomyces cerevisiae in the glucose xylose co-fermentation process are effectively improved, so that the production cost is effectively reduced when the saccharomyces cerevisiae is used for ethanol fermentation production by utilizing xylose-containing substrates such as lignocellulose raw material hydrolysate and the like, the production efficiency is improved, and the saccharomyces cerevisiae has great production and application values.
Description
Technical Field
The invention relates to the technical field of bioengineering, in particular to saccharomyces cerevisiae with improved xylose utilization efficiency, application thereof and a method for producing ethanol.
Background
Petrochemical resources are non-renewable resources, the socioeconomic development based on the petrochemical resources is at risk, and meanwhile, the exploitation and absolute carbon emission of the petrochemical resources also place great pressure on the environment. The production of fuels and chemicals from biomass is a major trend. No matter the production mode mainly uses low price grain crops such as corns and the like as main raw materials at present, or the production mode of lignocellulose raw materials such as agriculture and forestry waste and the like is advancing in all countries, the production mode has the characteristics of renewable raw materials and less pollution in the production process, and carbon is recycled due to carbon fixation in the raw material generating process and carbon release in the combustion process, so that the whole carbon emission is low.
At present, the main process of producing fuel and chemicals by taking biomass as a raw material is to convert starch in low-price grain crops such as corns and the like into glucose, and then the glucose is fermented to obtain products such as fuel ethanol and the like. However, this mode contends with humans and animals, and the production cost gradually increases as the price of the grain increases. The production route of lignocellulose raw materials such as agriculture and forestry waste and the like can fully utilize resources, promote employment and optimize industrial structures, so that the method has received extensive attention.
The lignocellulose raw material mainly comprises cellulose and hemicellulose, and glucose and xylose with the content of about 2:1 are obtained after hydrolysis. The full utilization of the two kinds of sugar is the basis for improving the utilization rate of raw materials and reducing the production cost. However, the safe and efficient glucose fermentation strain, saccharomyces cerevisiae, cannot metabolize xylose. Xylose metabolism is introduced and optimized through metabolism engineering, and the ability of saccharomyces cerevisiae to utilize xylose can be endowed. However, the xylose utilization efficiency is far lower than the glucose utilization efficiency, and the presence of glucose has a remarkable negative effect on xylose utilization, so that the improvement of the xylose utilization efficiency of the recombinant strain in glucose-xylose mixed fermentation is always a technical problem to be solved in the field.
Disclosure of Invention
The invention aims to overcome the problems in the prior art and provide saccharomyces cerevisiae with improved xylose utilization efficiency, application thereof and a method for producing ethanol. The saccharomyces cerevisiae provided by the invention has the advantage of improving the utilization rate of xylose in the glucose xylose co-fermentation process and simultaneously has the advantage of improving the accumulation amount of ethanol.
In order to achieve the above object, an aspect of the present invention provides a Saccharomyces cerevisiae having improved xylose utilization efficiency, which is selected from Saccharomyces cerevisiae having xylose metabolic pathway and the activity of transcription factor Skn7 is inhibited.
In a second aspect, the invention provides a method of increasing the xylose-utilizing growth capacity and/or increasing the xylose utilization efficiency of a Saccharomyces cerevisiae, the method comprising inhibiting the activity of the transcription factor Skn7 in the Saccharomyces cerevisiae, wherein the Saccharomyces cerevisiae is selected from the group consisting of Saccharomyces cerevisiae having a xylose metabolic pathway.
In a third aspect the present invention provides the use of Saccharomyces cerevisiae as described in the first aspect above and/or of a method as described in the second aspect above in the production of ethanol, in particular in the fermentation production of ethanol from a substrate comprising lignocellulose hydrolysate.
In a fourth aspect, the invention provides a method for producing ethanol, comprising fermenting a xylose-containing substrate with a saccharomyces cerevisiae and inhibiting the activity of a factor Skn7 in the saccharomyces cerevisiae, wherein the saccharomyces cerevisiae is selected from the group consisting of saccharomyces cerevisiae having a xylose metabolic pathway.
Through the technical scheme, the invention has the following beneficial effects:
(1) When the saccharomyces cerevisiae provided by the invention is used for fermentation production by adopting substrates containing xylose, glucose and other saccharides, the strain growth and the utilization efficiency of xylose are effectively improved, the problem that the existing xylose utilization strain has low utilization efficiency in a glucose-xylose co-fermentation system is solved, and meanwhile, the growth speed of the strain is improved, so that the fermentation process is accelerated, and the production efficiency is improved;
(2) The saccharomyces cerevisiae provided by the invention can also increase the accumulation amount of ethanol during glucose and xylose co-fermentation, so that the ethanol yield and the production efficiency can be improved during fermentation production by adopting the saccharomyces cerevisiae, the raw material utilization rate and the product yield can be improved, the production cost is further reduced, and the saccharomyces cerevisiae is very suitable for large-scale industrial production and application.
Drawings
FIG. 1 is a schematic diagram of the structure of the DNA fragment dSKN7-KanMX for gene knockout in example 1.
FIG. 2 is a graph showing the effect of the knockout of the SKN7 gene on ethanol fermentation of Saccharomyces cerevisiae BSGX001 at different carbon sources in example 3.
Detailed Description
The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.
In the invention, recombinant yeast BSGX001, or Saccharomyces cerevisiae BSGX001, refers to Saccharomyces cerevisiae with a preservation number of CGMCC No.17264, which is disclosed in CN201910304995.3. Saccharomyces cerevisiae SDIC Sc E01 refers to Saccharomyces cerevisiae accession number GDMCC No. 62491, which is disclosed in CN202210813571.1.
In the present invention, the transcription factor Skn7 is a transcription factor responding to heat shock and oxidative stress, and the nucleotide sequence of the coding Gene (SKN 7 Gene) is registered in GenBank with the accession number of Gene ID:856613.
In the present invention, inhibiting the activity of the transcription factor Skn7 means that the transcription factor Skn7 is not normally expressed by knocking out or mutating the Skn7 gene, or by interfering with the expression of the Skn7 gene, or the activity of the expressed transcription factor Skn7 is decreased or lost ("decrease or loss" means that the activity of the transcription factor Skn7 is decreased to 20% or less of the original activity, for example, to 20%, 18%, 15%, 12%, 10%, 5%, 2%, 1%, 0.5%, 0 of the original activity, or may be any intermediate value of any two of the above values).
The inventors of the present invention have found in the study that, when xylose metabolism pathway is introduced into s.cerevisiae, although the recombinant s.cerevisiae is enabled to utilize xylose, the production efficiency and yield of ethanol fermentation using xylose-containing substrate such as lignocellulose raw material hydrolysate are improved, the presence of other sugars (such as glucose, mannose, galactose, etc.) in the substrate has a negative effect on xylose metabolism, and even if these sugars are depleted, such negative effect is not eliminated, and therefore, it is necessary to improve the xylose utilization efficiency of the recombinant s.cerevisiae for xylose-containing substrate even further. As a result of studies, the inventors of the present invention have found that, when the activity of the transcription factor Skn7 in a recombinant yeast having a xylose metabolic pathway introduced therein is suppressed, the recombinant yeast is effective in improving the utilization efficiency of xylose in a substrate containing other saccharides such as xylose and glucose. Through further research, the inventor also discovers that inhibiting the activity of the transcription factor Skn7 can not only improve the utilization efficiency of the recombinant brewing wine with xylose metabolic pathways in a xylose and other sugar co-fermentation system on xylose, but also further improve the growth condition of thalli and improve the accumulation amount of ethanol.
Based on the above findings, the present invention provides, in a first aspect, a Saccharomyces cerevisiae having improved xylose utilization efficiency, selected from Saccharomyces cerevisiae having xylose metabolic pathway and having suppressed activity of transcription factor Skn 7.
According to a preferred embodiment of the present invention, wherein the Saccharomyces cerevisiae is selected from Saccharomyces cerevisiae CGMCC No.17264 and/or GDMCC No. 62491 (in which the activity of the transcription factor Skn7 is inhibited).
In the present invention, the specific mode of inhibiting the transcription factor Skn7 in Saccharomyces cerevisiae is not particularly limited, and any method that can achieve this object in the art can be applied to the present invention. For example, it may include knocking out the SKN7 gene, mutating the SKN7 gene to inactivate the expressed protein, introducing other foreign genes to interfere with the expression of the SKN7 gene, and the like.
In a second aspect, the invention provides a method of increasing the xylose-utilizing growth capacity and/or increasing the xylose utilization efficiency of a Saccharomyces cerevisiae, the method comprising inhibiting the activity of the transcription factor Skn7 in the Saccharomyces cerevisiae, wherein the Saccharomyces cerevisiae is selected from the group consisting of Saccharomyces cerevisiae having a xylose metabolic pathway.
In the present invention, the mode of inhibiting the activity of the transcription factor Skn7 in s.cerevisiae is not particularly limited as long as the activity can be reduced or lost (to the aforementioned extent). The method can be used for modifying Saccharomyces cerevisiae to inhibit the activity of the transcription factor Skn7, or can be used for inhibiting the activity of the transcription factor Skn7 by adding an additional reagent in the production process.
According to a preferred embodiment of the present invention, wherein the means for inhibiting the activity of the transcription factor Skn7 in Saccharomyces cerevisiae comprises: knocking out the SKN7 gene, mutating the SKN7 gene to make the expressed protein lose activity or interfere with the expression of the SKN7 gene, so that the SKN7 gene cannot be expressed or the activity of the expressed transcription factor Skn7 is reduced or lost. In the invention, the mode of interfering the expression of the SKN7 gene can comprise adding substances interfering the expression of the SKN7 gene in the fermentation process, or further modifying the Saccharomyces cerevisiae, introducing other exogenous genes interfering the expression of the SKN7 gene, and the like.
According to a preferred embodiment of the invention, the inhibition of the activity of the transcription factor Skn7 in Saccharomyces cerevisiae is carried out by knocking out the SKN7 gene.
According to a preferred embodiment of the present invention, wherein the Saccharomyces cerevisiae having a xylose metabolism pathway is selected from Saccharomyces cerevisiae CGMCC No.17264 and/or GDMCC No. 62491.
A third aspect of the invention provides the use of saccharomyces cerevisiae as described in the first aspect above and/or a process as described in the second aspect above in the production of ethanol. In particular to the application in ethanol fermentation production by using a substrate containing lignocellulose hydrolysate. For example, saccharomyces cerevisiae having the above characteristics is used for ethanol fermentation production using a substrate containing xylose and other sugars such as glucose as carbon sources. Or modifying Saccharomyces cerevisiae by the method, and then carrying out ethanol fermentation production by the modified Saccharomyces cerevisiae. Or when the saccharomyces cerevisiae with xylose metabolism is adopted and ethanol fermentation production is carried out by taking other saccharides such as xylose and glucose as carbon sources, substances which interfere with the expression of SKN7 genes are added, so that the utilization rate of the saccharomyces cerevisiae on xylose, the growth speed of strains and the like in the production process are improved.
In a fourth aspect, the invention provides a method for producing ethanol, comprising fermenting a xylose-containing substrate with a saccharomyces cerevisiae and inhibiting the activity of a factor Skn7 in the saccharomyces cerevisiae, wherein the saccharomyces cerevisiae is selected from the group consisting of saccharomyces cerevisiae having a xylose metabolic pathway.
In the present invention, the source and specific components of the substrate are not particularly limited as long as Saccharomyces cerevisiae can be used for ethanol fermentation. According to a preferred embodiment of the invention, the substrate comprises a lignocellulosic feedstock hydrolysate. For example, the lignocellulose raw material hydrolysate can be directly used as a fermentation substrate, or other reagents can be added on the basis of the lignocellulose raw material hydrolysate to prepare a substrate for ethanol fermentation by saccharomyces cerevisiae.
When a lignocellulose raw material hydrolysate is used as a fermentation substrate (one of the components), saccharides such as glucose, mannose and galactose contained in the hydrolysate can be utilized by Saccharomyces cerevisiae (through the existing natural utilization route) and converted into ethanol, but the existence of the saccharides has a negative effect on the utilization of xylose, so that the overall ethanol production efficiency and yield are influenced, and after the activity of a transcription factor Skn7 is inhibited, the utilization efficiency of xylose and the growth rate of strains of Saccharomyces cerevisiae are improved, so that the raw material utilization rate and the production efficiency are improved compared with those when the activity of Skn7 is not inhibited. Meanwhile, the utilization efficiency of saccharides available to other Saccharomyces cerevisiae is not adversely affected. Therefore, preferably, the substrate may further contain at least one of glucose, mannose and galactose as a carbon source.
According to a preferred embodiment of the invention, the weight ratio of glucose to xylose in the substrate is 1:0.5-5.
Preferably, the weight ratio of glucose to xylose is 1:0.5-1.5. For example, it may be 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, or any intermediate value between any two of the above ratios.
According to a preferred embodiment of the present invention, wherein the activity of the transcription factor SKN7 in s.cerevisiae is inhibited in such a way that the SKN7 gene is knocked out, the SKN7 gene is mutated so that the expressed protein is inactive or the expression of the SKN7 gene is disturbed. Preferably, the SKN7 gene is knocked out.
According to a preferred embodiment of the present invention, wherein the Saccharomyces cerevisiae having a xylose metabolism pathway is selected from Saccharomyces cerevisiae CGMCC No.17264 and/or GDMCC No. 62491.
In the present invention, the specific fermentation mode and conditions are not particularly limited. In order to further increase the ethanol production efficiency, according to a preferred embodiment of the present invention, wherein the conditions of the fermentation comprise an initial OD 600 =0.5-5, rotational speed 100-300rpm, temperature 25-35 ℃. Preferably, the fermentation time is 24-72 hours.
Preferably, the conditions of the fermentation include an initial OD 600 =0.5-2, rotational speed 150-250rpm, temperature 27-32 ℃.
The present invention will be described in detail by examples. It should be understood that the following examples are illustrative only and are not intended to limit the invention.
In the following examples, the starting strain BSGX001 (BSGX 001 for short) is a recombinant Saccharomyces cerevisiae introduced into and optimizing xylose metabolism, the preservation number of which is CGMCC No.17264, and the specific construction method is shown in CN201910304995.3. The original strain SDIC ScE 01 (DIC ScE 01 for short) is a recombinant saccharomyces cerevisiae which can endure a harsher fermentation environment and can be produced by ethanol fermentation by utilizing xylose and glucose more quickly, and the preservation number is GDMCC No. 62491, and the specific construction method is shown in CN202210813571.1. Unless specifically stated, reagents or materials used were all commercially available from regular biological or chemical reagent/material suppliers, and the reagents were all analytically pure.
The media used in the following examples are as follows:
YPD medium: the raw materials were weighed according to a dosage ratio of 2% by weight peptone, 1% by weight yeast powder, 2% by weight glucose and dissolved in deionized water. Sterilizing at 115deg.C for 30min, and cooling to obtain YPD liquid culture medium. Adding 2% of agar powder by weight before sterilization, cooling to a temperature below 50 ℃ after sterilization, pouring the agar powder into a plate, and cooling and solidifying to obtain the YPD culture plate.
Glucose-xylose co-sugar fermentation medium (glucose and xylose as carbon sources): according to yeast basic nitrogen source (YNB) 1.7g/L, (NH) 4 ) 2 SO 4 5 g/L, CSM-URA 0.77g/L, and dissolving in deionized water to prepare solution 1. Simultaneously, a 40 wt% glucose solution and a 40 wt% xylose solution were prepared. And (3) respectively carrying out high-pressure sterilization at 115 ℃ for 30min, cooling, and adding the sugar solution into the solution 1 according to the concentration of 20g/L glucose and 20g/L xylose to obtain the glucose-xylose co-sugar fermentation liquid culture medium.
In the following examples, the starting strain BSGX001 was engineered to inhibit the activity of its transcription factor Skn7 by knocking out the gene Skn7 using conventional techniques and methods used in the fields of genetic engineering and molecular biology. Specific methods can be found in Methods in yeast genetics and genomics: a Cold Spring Harbor Laboratory course manual 2015edition (Cold Spring Harbor, N.Y.: cold Spring HarborLaboratory Press, 2005).
Example 1PCR obtaining DNA fragments for Gene knockout
Using plasmid pUG6 (GenBank: AF 298793.1) as a template, dSKN7s and dSKN7a as primers (specific sequences are shown in Table 1), the KanMX expression cassette DNA fragment dSKN7-KanMX with the SKN7 homologous recombination arms was amplified using the system and conditions shown in Table 1 below.
TABLE 1
The structural schematic diagram of dSKN7-KanMX is shown in figure 1, wherein an upstream homology arm of SKN7 and a downstream homology arm of SKN7 are respectively homologous with upstream and downstream sequences of an SKN7 gene open reading frame on a chromosome; the KanMX expression frame refers to a whole DNA sequence with the same-direction loxP site at two ends and capable of expressing protein to make the strain have G418 resistance characteristic. Includes a promoter TEF promorter, an open reading frame KanR, and a terminator TEF terminator.
EXAMPLE 2 obtaining recombinant strain from which SKN7 Gene was knocked out
The starting strain BSGX001 was transformed with the fragment dSKN7-KanMX obtained in example 1, and transformants were obtained by screening on YPD plates containing 200. Mu.g/mL G418. The selected transformants were verified by extracting the chromosomes of the transformants and performing PCR verification (the primers, PCR system and conditions used are shown in Table 2), wherein the PCR product length was 1158bp, which is the correct transformant BSGX001 (skn. Delta.) with the knocked SNK7, and the transformants which failed to knock out could not obtain the PCR product. The DNA sequence of the SKN7 gene locus on the BSGX001 (SKN 7 delta) chromosome of the transformant was replaced with an expression cassette sequence, thereby rendering the transformant incapable of expressing the SKN7 transcription factor.
TABLE 2
Example 3 test of glucose xylose Co-fermentation Effect of mutant Strain
The original strain BSGX001 and the recombinant strain BSGX001 (skn delta) are respectively fermented and cultured in a glucose xylose co-fermentation culture medium, and the thallus growth condition, the xylose utilization rate and the ethanol accumulation amount of the original strain and the recombinant strain in the fermentation process are compared.
The operation process is as follows: inoculating the original strain and recombinant strain into SC-URA culture medium containing 20g/L glucose, culturing at 30deg.C for 14+ -2 hr, transferring strain into 300mL triangular flask containing 50mL SC-URA culture medium, and collecting carbon20g/L glucose, initial OD 600 1.0, 200rpm,30 ℃ for 12 hours. After the incubation, it was centrifuged at 5500rpm for 3 minutes, washed 1-2 times with sterile water, resuspended in 50mL glucose-xylose co-sugared fermentation medium, initial OD 600 =2.5, fermentation culture at 200rpm for 48h at 30 ℃.
For the cell amounts (OD) of the starting strain BSGX001 and the recombinant strain BSGX001 (skn. Delta.) during fermentation culture 600 The values were used as a judgment index), the concentration of glucose, xylose and ethanol in the fermentation system was monitored. Wherein, HPLC analysis of glucose, xylose and ethanol concentration uses a Bio-Rad LC-20A system, and chromatography column usesHPX-87H (Bio-Rad) was detected using a RID-10A differential detector from Bio-Rad. Mobile phase 5mmol/L H 2 SO 4 The flow rate was 0.6mL/min and the column oven temperature was maintained at 45 ℃. Xylose utilization rate was calculated using the following formula.
Where r is the xylitol ratio utilization rate from sampling point m to sampling point n stages; A. b and t are the xylose concentration, biomass concentration (i.e., dry weight of the cells, by applying a corresponding OD to the samples at points n, i and m, respectively 600 Centrifuging the fermentation broth, collecting thallus, oven drying, weighing, and measuring) and time.
The results are shown in FIG. 2, wherein "+.7-represents the cell mass of the strain BSGX001 at various time points during fermentation, using OD 600 A representation; ■ -represents the cell mass of the strain BSGX001 (skn 7.DELTA.) at various time points during the fermentation, expressed as OD 600; - Δ -represents the glucose concentration of strain BSGX001 at various time points during fermentation; -d-represents the glucose concentration of strain BSGX001 (skn delta) at various time points during fermentation;representative Strain BSGX001 during fermentationXylose concentrations at each time point; -t-represents the xylose concentration of strain BSGX001 (skn delta) at various time points during fermentation; o-represents the ethanol concentration of the strain BSGX001 at various time points during fermentation; - +..
As can be seen from FIG. 2, the recombinant strain BSGX001 (skn. Delta.) was superior to the starting strain BSGX001 in both strain growth and xylose utilization in glucose xylose co-fermentation.
Wherein, the bacterial amount of BSGX001 (skn delta) is 18.5 percent higher than that of BSGX001 after 48 hours of fermentation; the xylose volume utilization rate (xylose utilization amount/time) of the whole stage is 15.2 percent higher than BSGX001, and is increased from 0.22g/L/h to 0.26g/L/h; in the xylose utilization stage after glucose depletion, the xylose utilization rate of BSGX001 (skn delta) is 8% higher than that of BSGX001, and the xylose utilization rate is increased from 0.113+/-0.002 g/L/h/g dry weight cells to 0.122+/-0.002 g/L/h/g dry weight cells; meanwhile, the utilization rate of BSGX001 (skn 7 delta) is equivalent to that of glucose by the original strain; in addition, the accumulation of BSGX001 (skn 7. Delta.) ethanol was increased by 4% from 12.4.+ -. 0.1g/L to 12.9.+ -. 0.5 in 48 hours, as compared to the starting strain. The result shows that the mode of knocking out the SKN7 gene to ensure that the activity of the transcription factor Skn7 is lost can obviously improve the xylose utilization capacity of the saccharomyces cerevisiae BSGX001.
Example 4
The corresponding SKN7 gene knockout strain was prepared by the method of examples 1-2 using Saccharomyces cerevisiae SDIC Sc E01 as the starting strain.
By adopting the method in example 3, saccharomyces cerevisiae SDIC ScE 01 and the corresponding SKN7 gene knockout strain SDIC ScE 01 (SKN delta) are respectively fermented and cultured in a glucose xylose co-fermentation medium for 48 hours, and the thallus growth conditions of the original strain and the knockout strain in the fermentation process, the utilization rate of xylose and the accumulation amount of ethanol are compared.
The results are similar to BSGX001 and BSGX001 (skn. Delta.) in that the glucose utilization rates of SDIC ScE 01 and SDIC ScE 01 (skn. Delta.) are comparable, and the improvement amounts of the other parameters of SDIC ScE 01 (skn. Delta.) compared to SDIC ScE 01 are shown in Table 3 below.
TABLE 3 Table 3
| Increasing parameters | Increasing amount/% |
| Amount of cell | 16 |
| Xylose volume utilization rate throughout the stage | 15.7 |
| Xylose utilization stage xylose specific utilization rate | 7.8 |
| Ethanol accumulation for 48 hours | 5.2 |
The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, a number of simple variants of the technical solution of the invention are possible, including combinations of the individual technical features in any other suitable way, which simple variants and combinations should likewise be regarded as being disclosed by the invention, all falling within the scope of protection of the invention.
Claims (10)
1. A saccharomyces cerevisiae with improved xylose utilization efficiency, characterized in that it is selected from saccharomyces cerevisiae with xylose metabolic pathway and with suppressed activity of transcription factor Skn 7.
2. Saccharomyces cerevisiae according to claim 1, wherein the Saccharomyces cerevisiae is selected from Saccharomyces cerevisiae CGMCC No.17264 and/or GDMCC No. 62491.
3. A method of increasing the growth capacity of saccharomyces cerevisiae for xylose utilization and/or increasing the efficiency of xylose utilization by saccharomyces cerevisiae, comprising inhibiting the activity of the transcription factor Skn7 in saccharomyces cerevisiae, wherein the saccharomyces cerevisiae is selected from the group consisting of saccharomyces cerevisiae with a xylose metabolic pathway.
4. A method according to claim 3, wherein the means for inhibiting the activity of the transcription factor Skn7 in saccharomyces cerevisiae comprises: the SKN7 gene is knocked out, the mutant SKN7 gene is used for inactivating the expressed protein or interfering the expression of the SKN7 gene, and the SKN7 gene is knocked out preferably.
5. The method according to claim 3 or 4, wherein the saccharomyces cerevisiae is selected from saccharomyces cerevisiae CGMCC No.17264 and/or GDMCC No. 62491.
6. Use of a saccharomyces cerevisiae according to claim 1 or 2 and/or of a method according to any of claims 3-5 in the production of ethanol, in particular in the fermentation production of ethanol with substrates containing lignocellulose hydrolysates.
7. A method for producing ethanol, comprising fermenting a xylose-containing substrate with saccharomyces cerevisiae and inhibiting the activity of a transcription factor Skn7 in the saccharomyces cerevisiae, wherein the saccharomyces cerevisiae is selected from the group consisting of saccharomyces cerevisiae having a xylose metabolic pathway.
8. The method of claim 7, wherein the substrate comprises a lignocellulosic feedstock hydrolysate;
preferably, the substrate further contains at least one of glucose, mannose and galactose as a carbon source;
more preferably, the weight ratio of glucose to xylose in the substrate is 1:0.5-5;
and/or the saccharomyces cerevisiae is selected from saccharomyces cerevisiae CGMCC No.17264 and/or GDMCC No. 62491.
9. The method of claim 7, wherein the activity of the transcription factor SKN7 in s.cerevisiae is inhibited by knocking out the SKN7 gene, mutating the SKN7 gene such that the expressed protein is inactive or interfering with the expression of the SKN7 gene.
10. The method of claim 7, wherein the conditions of the fermentation comprise an initial OD 600 =0.5-5, rotational speed 100-300rpm, temperature 25-35 ℃.
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