CN109825489A

CN109825489A - A kind of beta amylase and its application with hypersecretion ability

Info

Publication number: CN109825489A
Application number: CN201910249596.1A
Authority: CN
Inventors: 段绪果; 张心怡; 朱秋雨; 沈镇炎; 郭双凤; 程欣; 陶钰清
Original assignee: Nanjing Forestry University
Current assignee: Nanjing Forestry University
Priority date: 2019-03-29
Filing date: 2019-03-29
Publication date: 2019-05-31
Anticipated expiration: 2039-03-29
Also published as: CN109825489B

Abstract

The invention discloses a kind of beta amylase with hypersecretion ability and its applications, belong to genetic engineering and microbial engineering field.Beta amylase of the invention has hypersecretion ability, the Escherichia coli shake flask fermentation 48h of beta amylase of the present invention will be carried, the beta amylase enzyme activity in fermented supernatant fluid can be made to be up to 434.65U/mL, the Escherichia coli of the beta amylase of the present invention Fiber differentiation 30h in 3L fermentor will be carried, the beta amylase enzyme activity in fermented supernatant fluid can be made to be up to 13063.8U/mL, therefore, beta amylase of the invention is suitable for large-scale industrial production.

Description

A kind of beta amylase and its application with hypersecretion ability

Technical field

The present invention relates to a kind of beta amylase with hypersecretion ability and its applications, belong to enzyme engineering and microbial project Technical field.

Background technique

Beta amylase (EC 3.2.1.2, saccharogen amylase, glycogenase) is a kind of with systematic name 4- α-D- glucan The enzyme of malto-hydrolase belongs to GH14 family, is a kind of exoenzyme to work from non-reducing end, can be catalyzed second α-Isosorbide-5-Nitrae Hydrolysis of glycoside bond once cracks two glucose units (maltose).Therefore, beta amylase may act on starch, glycogen, correlation Polysaccharide and by be inverted generate beta-maltose oligosaccharides, be brewing, maltose (malt syrup) manufacture main saccharifying agent, Consequence is occupied in food, medicine and other fields.

Beta amylase can be extracted from plant and microorganism and be obtained.Currently, the beta amylase of commercialization is mainly from plant Middle extract obtains, and the beta amylase for extracting plant origin need to consume a large amount of higher plant, such as barley, wheat, rye, big Seed and the stem tuber of sweet potato of beans etc., therefore, the beta amylase for extracting plant origin will cause great foodstuff waste, compare For, it is lower and without foodstuff waste that beta amylase cost is produced by microbial fermentation, is a kind of better choice.

But so far, it still has in terms of through Production by Microorganism Fermentation beta amylase and much asks both at home and abroad Topic, wherein beta amylase low output caused by secretion level is insufficient be influence its large-scale industrial production key factor it One.For example, A.NIPKOW et al. has obtained to produce the pyrolysis sulphur clostridium (Clostridium of beta amylase by continuously culture Thermosulfurogenes) engineering bacteria, still, the beta amylase enzyme activity by this engineering bacterium fermentation 46h, in fermented supernatant fluid Only 90U/mL；Guo Rui et al. is huge by realizing in bacillus licheniformis (Bacillus licheniformis) expression system The efficient heterogenous expression of Bacterium anthracoides (Bacillus megatherium) source beta amylase has obtained that β-starch can be produced Bacillus licheniformis (Bacillus licheniformis) genetic engineering bacterium of enzyme, still, for 24 hours by this engineering bacterium fermentation, Beta amylase enzyme activity in fermented supernatant fluid only has 226.7U/mL；Li Youran et al. passes through in bacillus subtilis (Bacillus Subtilis the beta amylase gene in efficient inducing expression bacillus megaterium (Bacillus megatherium) source obtains in) To bacillus subtilis (Bacillus subtilis) genetic engineering bacterium that can produce beta amylase, still, by this engineering bacteria For 24 hours, the beta amylase enzyme activity in fermented supernatant fluid only has 97.16U/mL, and industrial life is much not achieved in above-mentioned yield for fermentation The requirement of production.Therefore, it is badly in need of obtaining a kind of yield of the beta amylase with hypersecretion ability to improve beta amylase.

In addition, it is noted that by Production by Microorganism Fermentation beta amylase, there is also much ask in addition to low output Topic, for example, the enzyme pH adaptability obtained is poor, catalytic activity is low etc., these problems also can be to passing through Production by Microorganism Fermentation The process of industrialization of beta amylase adversely affects, it would be highly desirable to solve.

Summary of the invention

[technical problem]

The technical problem to be solved by the present invention is to obtain a kind of beta amylase with hypersecretion ability to improve β-starch The yield of enzyme.

[technical solution]

To solve the above problems, the present invention provides a kind of beta amylase with hypersecretion ability, the beta amylase Amino acid sequence as shown in SEQ ID No.1.

The present invention also provides the genes for encoding above-mentioned beta amylase.

In one embodiment of the invention, the nucleotide sequence of the gene is as shown in SEQ ID No.2.

The present invention also provides the recombinant plasmids for carrying said gene.

In one embodiment of the invention, the carrier of the recombinant plasmid is pET carrier, pUC carrier, pT7-7 load Body or pGEX carrier.

In one embodiment of the invention, the carrier of the recombinant plasmid is pET-20b (+) carrier.

The present invention also provides the host cells for carrying said gene or above-mentioned recombinant plasmid.

In one embodiment of the invention, the host cell is bacterium or fungi.

In one embodiment of the invention, the host cell is Escherichia coli.

The present invention also provides the preparation method of above-mentioned beta amylase, the method is that above-mentioned host cell is seeded to hair It ferments in ferment culture medium.

The present invention also provides the beta amylases being prepared using the above method.

The present invention also provides above-mentioned beta amylase or said gene or above-mentioned recombinant plasmid or above-mentioned host cell or on State the application of preparation method or the above-mentioned beta amylase being prepared in terms of hydrolyzing starch.

The present invention also provides a kind of method for producing maltose, the method is by above-mentioned beta amylase or above-mentioned host Cell or the above-mentioned beta amylase being prepared are added in starch and/or dextrin and are digested.

[beneficial effect]

(1) beta amylase of the invention has hypersecretion ability, will carry the Escherichia coli shaking flask of beta amylase of the present invention Ferment 48h, and the beta amylase enzyme activity in fermented supernatant fluid can be made to be up to 434.65U/mL, will carry the big of beta amylase of the present invention Enterobacteria Fiber differentiation 30h in 3L fermentor can make the beta amylase enzyme activity in fermented supernatant fluid be up to 13063.8U/mL, Therefore, beta amylase of the invention is suitable for large-scale industrial production；

(2) beta amylase of the invention is more stable in the environment of pH is 5.0~7.0, with the enzyme activity under optimal pH Compared to not varying widely, it is seen then that beta amylase of the invention has wider pH adaptation range, the more production advantage；

(3) beta amylase of the invention all has higher catalysis and lives when substrate is soluble starch and cornstarch Property, wherein when substrate is soluble starch, the maximum reaction rate (V of beta amylase of the present invention_max), catalytic constant (K_cat), bottom Object affinity (K_m) and catalytic efficiency (K_cat/K_m) respectively up to 6660 μm of ol/min/mg, 116961.11/s, 9.97mg/mL, 11733.66mL/s/mg, and cost is relatively low for soluble starch and cornstarch, it is seen then that beta amylase of the invention is producing Advantage is had more in efficiency and production cost, and there are the potentiality suitable for industrialized production and application.

Detailed description of the invention

Fig. 1: recombinant bacterium E.coli BL21 (DE3)/PET20b (+)-amy-1 fermentation liquid fermented supernatant fluid component, loading The SDS-PAGE electrophoresis result of sample component and pure enzyme component；

Wherein, M is Protein Marker；1 is fermented supernatant fluid component；2 be loading sample component；3 be pure enzyme component.

Fig. 2: enzyme activity variation of the beta amylase of the present invention under condition of different pH.

Fig. 3: the enzyme activity after beta amylase of the present invention saves for 24 hours under condition of different pH changes.

Fig. 4: enzyme activity variation of the beta amylase of the present invention under condition of different temperatures.

Fig. 5: the enzyme activity during beta amylase of the present invention saves 2.5h under condition of different temperatures changes.

Fig. 6: specific variations of the beta amylase of the present invention to different substrates.

Specific embodiment

Combined with specific embodiments below, the present invention will be further elaborated.

E. coli BL21 (DE3), e. coli jm109 involved in following embodiments are purchased from Beijing Suo Lai Precious Science and Technology Ltd., pET-20b (+) carrier are purchased from Novagen company；Sweet potato beta amylase involved in following embodiments (traditional Chinese medicines coding: SA700501), soya-beta amylase (traditional Chinese medicines coding: TA044801), soluble starch, dextrin DE15-20, paste Smart DE10-15, maltodextrin DE8-10, cornstarch, tapioca, potato starch are limited purchased from Chinese medicines group chemical reagent Company.

(above-mentioned bacterial strains E. coli BL21 (DE3), e. coli jm109 can be commercially available, and not needed Carry out the preservation for proprietary program)

Culture medium involved in following embodiments is as follows:

LB liquid medium: yeast powder 5.0gL^-1, tryptone 10.0gL^-1、NaCl 10.0g·L^-1。

LB solid medium: yeast powder 5.0gL^-1, tryptone 10.0gL^-1、NaCl 10.0g·L^-1, agar powder 15g/L。

TB culture medium: glycerol 5.0gL^-1, tryptone 12.0gL^-1, yeast powder 24.0gL^-1、K₂HPO₄·3H₂O 16.4g·L^-1、KH₂PO₄2.3g·L^-1, glycine 7.5gL^-1。

Detection method involved in following embodiments is as follows:

The measuring method of beta amylase enzyme activity:

Saccharometry is restored referring to DNS；Drawing 500 μ L substrates respectively, (substrate used is that the soluble of 2% (m/m) is formed sediment Powder solution, soluble starch solution are prepared with the deionized water of pH6.0) and 400 μ LpH for 6.0 Na₂HPO₄Lemon acid buffering Liquid is added in the tool plug test tube of 15mL, and mixing, which is placed in 50 DEG C of water-baths, to be preheated, and the enzyme after dilution is added after 10min 100 μ L of liquid simultaneously shakes mixing, and 800 μ L DNS are added after 10min and are placed in boiling water bath 5min to develop the color, stand after boiling water bath It is put into cooling in ice water quarter, then distinguishes constant volume to 15mL with deionized water, concussion mixes, and extinction is measured at wavelength 540nm Degree, to use the enzyme solution inactivated in boiling water as the control group of measurement, standard curve by various concentration gradient maltose solution It is made as normal concentration.

Enzyme activity (U) is defined as: under above-mentioned analysis determination condition, catalysis generates and is equivalent to 1 μm of ol maltose per minute The enzyme amount of reducing power is defined as a unit of activity (1U).

Embodiment 1: the building of the recombinant bacterium containing nucleotide sequence beta amylase gene as shown in SEQ ID No.2

Specific step is as follows:

It designs and one section of nucleotide sequence of chemical synthesis beta amylase gene as shown in SEQ ID No.2 is (with this β-shallow lake The amino acid sequence of the corresponding beta amylase of powder enzyme gene is as shown in SEQ ID No.1), by this beta amylase gene with PET20b (+) carrier is connected through double digestion (restriction enzyme site Nco I, Hind III), after digestion products are tapped and recovered, then is connected with T4 Enzyme connects 12h at 16 DEG C, and connection product converts escherichia coli jm109 competent cell, and converted product is coated on containing 100mg/L The LB solid medium of ammonia jasmine penicillin selects the LB of transformant access ampicillin containing 100mg/L in 37 DEG C of culture 12h Fluid nutrient medium extracts plasmid after shaking table culture 10h under conditions of 37 DEG C, 200rpm, obtains recombinant plasmid PET20b (+)- amy-1；

By recombinant plasmid PET20b (+)-amy-1 thermal shock Transformed E .coli BL21 (DE3) competent cell, converted product It is coated on the LB solid medium of the jasmine penicillin of ammonia containing 100mg/L, in 37 DEG C of culture 12h, transformant is selected, obtains recombinant bacterium E.coli BL21(DE3)/PET20b(+)-amy-1。

Comparative example 1: the building of the recombinant bacterium containing other beta amylase genes

Specific step is as follows:

Separate sources beta amylase (respectively nucleotide sequence source as shown in SEQ ID No.3 is obtained from NCBI Bacillus is derived from as shown in SEQ ID No.4 in beta amylase, the nucleotide sequence of Bacillus aryabhattai Sp. beta amylase, nucleotide sequence derives from β-starch of Bacillus aryabhattai as shown in SEQ ID No.5 Enzyme, nucleotide sequence derive from beta amylase, the nucleotides sequence of Bacillus megaterium as shown in SEQ ID No.6 Arrange such as SEQ ID No.7 shown in derive from Bacillus sp. beta amylase) nucleotide sequence, by it is artificial synthesized must To after these sequences, then obtained sequence is connected respectively on pET20b (+) carrier and converts host cell E.coli BL21 (DE3) obtains recombinant bacterium E.coli BL21 (DE3)/PET20b (+)-amy-2, E.coli BL21 (DE3)/PET20b (+)-amy-3, E.coli BL21 (DE3)/PET20b (+)-amy-4, E.coli BL21 (DE3)/PET20b (+)-amy-5 with And E.coli BL21 (DE3)/PET20b (+)-amy-6.

Embodiment 2: the preparation of different beta amylases and the detection of different beta-amylase secretion ability

Specific step is as follows:

Recombinant bacterium E.coli BL21 (DE3)/PET20b (+)-amy-1 that picking embodiment 1 and comparative example 1 are prepared, E.coli BL21(DE3)/PET20b(+)-amy-2、E.coli BL21(DE3)/PET20b(+)-amy-3、E.coli BL21 (DE3)/PET20b (+)-amy-4, E.coli BL21 (DE3)/PET20b (+)-amy-5 and E.coli BL21 (DE3)/ PET20b (+)-amy-6 single colonie is inoculated into LB liquid medium respectively, the shaking table culture under conditions of 37 DEG C, 200rpm 8h obtains seed liquor；2.5mL seed liquor is taken to be added in TB culture medium respectively again, shaking table is trained under conditions of 37 DEG C, 200rpm After supporting 4h, the sweet continuation Fiber differentiation 48h of 4mg/L isopropylthio-D- galactolipin is added, obtains recombinant bacterium E.coli BL21 (DE3)/PET20b (+) fermentation liquid A, E.coli BL21 (DE3)/PET20b (+)-amy-2 that-amy-1 ferments ferment To fermentation liquid B, E.coli BL21 (DE3)/PET20b (+)-amy-3 the fermentation liquid C, E.coli BL21 that ferment (DE3)/PET20b (+) fermentation liquid D, E.coli BL21 (DE3)/PET20b (+)-amy-5 that-amy-4 ferments ferment To the fermentation liquid F that ferments of fermentation liquid E and E.coli BL21 (DE3)/PET20b (+)-amy-6.

Fermentation liquid A~F is centrifuged 5min under conditions of 8000rpm, obtains fermented supernatant fluid A~F, detects fermentation supernatant Beta amylase enzyme activity in liquid A~F, testing result are as follows: the beta amylase enzyme activity in fermented supernatant fluid A is 434.65U/mL, sends out Beta amylase enzyme activity in ferment supernatant B is 398.42U/mL, the beta amylase enzyme activity in fermented supernatant fluid C is 403.81U/ Beta amylase enzyme activity in mL, fermented supernatant fluid D is 356.76U/mL, the beta amylase enzyme activity in fermented supernatant fluid E is Beta amylase enzyme activity in 238.94U/mL, fermented supernatant fluid F is 191.38U/mL.

As it can be seen that nucleotide sequence beta amylase gene secretion ability as shown in SEQ ID No.2 is stronger.

Embodiment 3: the purifying of amino acid sequence beta amylase as shown in SEQ ID No.1

Specific step is as follows:

Determine that the ammonium sulfate of 70% (w/v) makes beta amylase saltout completely just by the method for ammonium sulfate precipitation, Therefore, the ammonium sulfate for 70% (w/v) being slowly added in the fermented supernatant fluid A that embodiment 2 obtains is saltoutd, after 12h, in 8000rpm, 10min is centrifuged under conditions of 4 DEG C, precipitated；It will be precipitated with appropriate amount of buffer solution A (20mM PBS, pH 7.5) molten It solves, filters (0.22 μm) through film after 4 DEG C of dialysis 12h, obtain loading sample；DEAE anion-exchange column is balanced with buffer solution A Loading afterwards, successively with buffer solution A, the buffer solution A of the NaCl containing 0~1M, the sodium chloride containing 1M buffer solution A elution of bound albumen, stream Speed is 1mL/min, obtains pure enzyme.

It detects the enzyme activity of pure enzyme and collects enzyme activity component and carry out protein electrophoresis analysis (protein electrophoresis analysis is with purchased from green cloud The protein molecular weight standard (14.4-116kD) of its biotech company is standard items), the results show that the amino finally obtained The specific enzyme activity of acid sequence pure enzyme of beta amylase as shown in SEQ ID No.1 is 3798.9U/mg, purification 8.8, yield For 14.2% (can specifically be shown in Table 1), amino acid sequence beta amylase as shown in SEQ ID No.1 is a band after purification, point Son amount is about 57.6kDa (specific visible Fig. 1)；

Wherein, specific enzyme activity refers to enzyme activity possessed by every milligram of zymoprotein, and unit is U/mg, its calculation formula is: ratio Enzyme activity=enzyme activity (U)/total protein (mg)；

Purification refers to the multiple that the Rate activity of enzyme after purification is improved than purifying the Rate activity of preferment, calculation method/ Formula are as follows: Rate activity/purifying preferment Rate activity of the enzyme of purification=after purification；

The rate of recovery refers to the total activity of enzyme and the ratio between the total activity of the purification step preferment after certain purification step, calculating side Method/formula are as follows: the total activity of enzyme/purification step preferment total activity after the rate of recovery=certain purification step.

The purifying of 1 amino acid sequence of table beta amylase as shown in SEQ ID No.1

Purification step	Total protein (mg)	Enzyme activity (U)	Rate activity (U/mg)	Purification	The rate of recovery (%)
						Fermented supernatant fluid	174.5	75629.1	433.4	1	100
Loading sample	41.3	30970.2	749.9	1.7	41
						Pure enzyme	0.8	3039.1	3798.9	8.8	14.2

Embodiment 4: the zymologic property research of amino acid sequence beta amylase as shown in SEQ ID No.1

Specific step is as follows:

(1) optimal pH and pH stability of amino acid sequence beta amylase as shown in SEQ ID No.1

Secure ph is respectively 4.0,5.0,6.0,7.0,8.0 Na₂HPO₄Citrate buffer solution is living instead of beta amylase Buffer in power measuring method, at 50 DEG C measure beta amylase vigor, with enzyme activity it is highest be 100%, remaining enzyme activity with Compared to opposite enzyme activity is calculated, to investigate the most suitable action pH of enzyme (testing result is shown in Fig. 2)；

Secure ph is respectively 4.0,5.0,6.0,7.0,8.0 Na₂HPO₄Citrate buffer solution is living instead of beta amylase Buffer in power measuring method, the enzyme that purifying is obtained is respectively under above-mentioned buffer system after 4 DEG C save for 24 hours, at 50 DEG C Lower measurement beta amylase vigor, with initial enzyme activity for 100%, enzyme activity calculates residual enzyme activity by comparison after preservation, to investigate it PH stability (testing result is shown in Fig. 3).

As shown in Figure 2, the optimal pH of amino acid sequence beta amylase as shown in SEQ ID No.1 is 6.0, this is most suitable The beta amylase of pH and most of other kinds of bacterial origins are very close, and when pH is 5.0~7.0, amino acid sequence is such as Beta amylase shown in SEQ ID No.1 is more stable, saves the 60% of highest enzyme activity, still, when pH lower than 5.0 or When higher than 7.0, the activity decline of amino acid sequence beta amylase as shown in SEQ ID No.1 is quickly.

As shown in figure 3, after saving a period of time under conditions of pH is 5.0~7.0, amino acid sequence such as SEQ ID Beta amylase shown in No.1 is more stable, illustrates it with wider pH adaptation range.

(2) optimum temperature and temperature stability of amino acid sequence beta amylase as shown in SEQ ID No.1

The Na that secure ph is 6.0₂HPO₄Citrate buffer solution replaces the buffer in beta amylase vigour-testing method, Respectively under conditions of 30 DEG C, 40 DEG C, 50 DEG C, 60 DEG C, 70 DEG C measure beta amylase enzyme activity, with enzyme activity it is highest be 100%, Remaining enzyme activity calculates opposite enzyme activity by comparison, to investigate the optimum temperature of enzyme (testing result is shown in Fig. 4)；

The Na that secure ph is 6.0₂HPO₄Citrate buffer solution replaces the buffer in beta amylase vigour-testing method, The obtained enzyme of purifying is kept the temperature into 2.5h under conditions of 50 DEG C, takes out part enzyme solution every 0.5h, it is cooling rapidly, 50 DEG C, Its beta amylase vigor is measured under the conditions of pH 6.0, with initial enzyme activity for 100%, enzyme activity calculates residual enzyme by comparison after heat preservation It is living, to investigate its temperature stability (testing result is shown in Fig. 5).

As shown in Figure 4, the optimum temperature of amino acid sequence beta amylase as shown in SEQ ID No.1 is 50 DEG C, and Still there is 94% activity at 55 DEG C.

As shown in Figure 5, amino acid sequence beta amylase as shown in SEQ ID No.1 is after 50 DEG C of heat preservation 2.5h, enzyme activity 40% or less can be dropped quickly to.

(3) kinetic parameter of amino acid sequence beta amylase as shown in SEQ ID No.1

Using the soluble starch of various concentration (0.5~40mg/mL) as substrate, β-is measured under the conditions of 50 DEG C, 6.0 pH Amylase initially hydrolyzes vigor, is intended using the non-linear regression method in 7.0 software of Graph Pad Prism data It closes, respectively obtains the K of Michaelis (Michaelis-Menten) equation_mAnd V_maxValue, then K is calculated_catAnd K_cat/K_mValue；

K_catThe calculation formula of value are as follows: K_cat=V_max/M/56676/60；Wherein, M is the quality for the enzyme being added in reaction, single Position is mg.

The results show that maximum of the amino acid sequence beta amylase as shown in SEQ ID No.1 to soluble starch substrate Reaction rate (V_max), catalytic constant (K_cat), substrate affinity (K_m) and catalytic efficiency (K_cat/K_m) it is respectively 6660 μm of ol/ Min/mg, 116961.11/s, 9.97mg/mL, 11733.66mL/s/mg, this illustrate beta amylase catalytic activity of the present invention compared with It is high.

(4) substrate specificity of amino acid sequence beta amylase as shown in SEQ ID No.1

Respectively with the soluble starch of 2% (m/m), dextrin DE15-20, dextrin DE10-15, maltodextrin DE8-10, jade Rice starch, tapioca are that substrate is 100% so that it is highest initially to hydrolyze vigor under the conditions of 50 DEG C, 6.0 pH, at the beginning of remaining Beginning hydrolysis vigor calculates relatively initial hydrolysis vigor of the beta amylase under different substrates by comparison (testing result is shown in Fig. 6).

It will be appreciated from fig. 6 that amino acid sequence beta amylase as shown in SEQ ID No.1 has when substrate is soluble starch There is maximum enzyme activity, and amino acid sequence beta amylase as shown in SEQ ID No.1 still has when substrate is cornstarch The 95% hydrolysis vigor when substrate is soluble starch.

(5) influence of metal-chelator and metal ion to amino acid sequence beta amylase as shown in SEQ ID No.1

The Na that secure ph is 6.0₂HPO₄Citrate buffer solution replaces the buffer in beta amylase vigour-testing method, By metal ion Cu²⁺, Zn²⁺, Fe²⁺, Ca²⁺, Mn²⁺, Co²⁺And Mg²⁺And metal-chelator EDTA mother liquor is separately added into test tube and makes Metal ion Cu²⁺, Zn²⁺, Fe²⁺, Ca²⁺, Mn²⁺, Co²⁺And Mg²⁺And the final concentration of metal-chelator EDTA mother liquor in test tube point Not Wei 1mM and 5mM, mixed liquor is obtained, under the conditions of 50 DEG C, 6.0 pH, to be added without the sample of metal ion and metal-chelator The enzyme activity of product (Control group) measurement is 100%, remaining enzyme activity calculates beta amylase by comparison and chelates in different metal Enzyme activity (the results are shown in Table 2) under agent and metal ion.

As shown in Table 2, most of enzyme activity determination results that metal ion is added are not much different with Control group, only Co² ⁺、Zn²⁺Enzyme activity be significantly improved, it was demonstrated that Co²⁺、Zn²⁺To amino acid sequence beta amylase as shown in SEQ ID No.1 Catalysis reaction has certain facilitation.

The influence of 2 metal ion of table and metal-chelator to enzyme activity

Metal ion or chelating agent (1mM)	Relative activity^*	Metal ion or chelating agent (5mM)	Relative activity
				Control	100	Control	100
Cu²⁺	93.91	Cu²⁺	38.61
				Zn²⁺	98.78	Zn²⁺	115.20
Fe²⁺	88.42	Fe²⁺	84.65
				Ca²⁺	99.39	Ca²⁺	94.13
Mn²⁺	115.11	Mn²⁺	114.44
				Co²⁺	95.00	Co²⁺	85.56
Mg²⁺	94.52	Mg²⁺	96.24
				EDTA	75.02	EDTA	62.84

Embodiment 5: the production of amino acid sequence beta amylase as shown in SEQ ID No.1

Specific step is as follows:

(1) seed culture:

The recombinant bacterium E.coli BL21 (DE3) that picking embodiment 1 is prepared/PET20b (+)-amy-1 single colonie access The LB liquid medium of the ampicillin containing 100mg/L, shaking table culture 8h, obtains seed liquor under conditions of 37 DEG C, 200rpm； It takes 2.5mL seed liquor to be added in TB culture medium, under conditions of 37 DEG C, 200rpm after shaking table culture 4h, 4mg/L isopropyl is added The sweet continuation Fiber differentiation 48h of the thio-D- galactolipin of base,

(2) enzymatic production:

The batch fermentation stage: by seed liquor, with 5% inoculum concentration access fermentation medium, (ingredient of fermentation medium includes sweet Oily 6g/L, peptone 12g/L, yeast powder 24g/L, KH₂PO₄2.31g/L、K₂HPO₄·3H₂O 16.43g/L, liquid microelement 10mL/L and ampicillin 100mg/L, wherein the ingredient of liquid microelement includes FeSO₄·7H₂O 10g/L、ZnSO₄· 7H₂O 2.25g/L、CuSO₄·5H₂O 1.0g/L、MnSO₄·4H₂O 0.5g/L、Na₂B₄O₇·10H₂O 0.23g/L、 CaCl₂2.0g/L、(NH₄)₆Mo₇O₂₄0.1g/L), so that dissolved oxygen is maintained 30% by control speed of agitator and ventilation quantity, control temperature It is 37 DEG C, stream plus mass concentration are 25% ammonium hydroxide control pH 7.0, are cultivated 6~7 hours；

The fed-batch fermentation stage: 80~100% are risen to dissolved oxygen, after batch experiments, is mended in a manner of exponential fed-batch It is subject to feed supplement liquid (glycerol 500g/L, MgSO that glycerol is carbon source₄·7H₂O 20g/L, peptone 15g/L, yeast powder 30g/L), Make thallus with 0.2h^-1Specific growth rate grown, control 37 DEG C of temperature, dissolved oxygen maintains 30%, is by mass concentration 25% ammonium hydroxide controls pH 7.0；

The Fiber differentiation stage: as thallus OD₆₀₀When reaching 50, temperature is reduced to 30 DEG C, dissolved oxygen maintains 30%, with 0.8g/ The flow velocity of L/h continuously adds 200g/L lactose solution, meanwhile, dissolved oxygen control controls pH 7.0 ± 0.5, induction 20~30% 30 hours, obtain fermentation liquid.

Fermentation liquid is centrifuged 10min under conditions of 8000rpm, obtains fermented supernatant fluid, is detected in fermented supernatant fluid Beta amylase enzyme activity, testing result are as follows: the beta amylase enzyme activity in fermented supernatant fluid is 13063.8U/mL.

Embodiment 6: the application (production maltose) of amino acid sequence beta amylase as shown in SEQ ID No.1

Specific step is as follows:

(1) it liquefies:

100mL deionized water is added to round-bottomed flask, and places it in 60 DEG C of water-baths and preheats 10min, by 10% (w/v) potato starch is added in additive amount, and is persistently stirred with blender, adjusts pH with the sodium hydroxide and hydrochloric acid solution of 1M 15min is kept the temperature after to 6.0, alpha-amylase is added with the amount of 12U/g dried starch, water bath temperature is risen to 90 DEG C, keeps the temperature 10 points Clock obtains liquefaction potato starch；

(2) it reacts:

After liquefaction, liquefaction potato starch is dispensed into conversion triangular flask, and be separately added into amino acid sequence such as Beta amylase shown in SEQ ID No.1, sweet potato beta amylase and soya-beta amylase, enzyme concentration are 50U/g dried starch, will be turned Change triangular flask to be placed in 55 DEG C of shaking baths, revolving speed is set as 150rpm, and reaction boils sample afterwards for 24 hours and terminates reaction, by 1:1's Acetonitrile is added in ratio, and standing 1~2h precipitates long-chain sugar, is then centrifuged for taking supernatant, with the yield of HPLC detection product；

HPLC carries out detection chromatographic condition are as follows: Yi Lite HPLC system；Detector: Shodex RI-201H；Nh 2 column: Thermo Hypersil APS-2NH2, mobile phase use the mixed solution of 70% (v/v) acetonitrile and deionized water, take out after mixing Filter；35 DEG C of detector temperature of setting, 35 DEG C of column temperature, flow velocity 1mL/min.

Testing result is shown: amino acid sequence beta amylase converted starch as shown in SEQ ID No.1 prepares maltose Conversion ratio be 76.1%, be under the same terms respectively using sweet potato beta amylase and soya-beta amylase conversion ratio 106.7% and 107.7%；

Wherein, calculation method/formula of conversion ratio are as follows: maltose conversion ratio (%)=(quality/starch matter of maltose Amount) × 100%.

Although the present invention has been described by way of example and in terms of the preferred embodiments, it is not intended to limit the invention, any to be familiar with this skill The people of art can do various change and modification, therefore protection model of the invention without departing from the spirit and scope of the present invention Enclosing subject to the definition of the claims.

Sequence table

<110>Nanjing Forestry University

<120>a kind of beta amylase and its application with hypersecretion ability

<160> 7

<170> PatentIn version 3.3

<210> 1

<211> 545

<212> PRT

<213>artificial sequence

<400> 1

Met Lys Gln Leu Cys Lys Lys Gly Leu Ala Phe Ile Leu Val Leu Ile

1 5 10 15

Phe Val Asn Ala Phe Ile Leu Asn Pro Leu Asn Gly Ala Ala Ala Val

20 25 30

Asp Gly Lys Ser Met Asn Pro Gly Tyr Lys Thr Tyr Leu Met Ala Pro

35 40 45

Leu Lys Lys Val Thr Asp Tyr Thr Thr Trp Glu Ala Phe Glu Asn Asp

50 55 60

Leu Arg Lys Ala Lys Gln Asn Gly Phe Tyr Ala Val Thr Val Asp Phe

65 70 75 80

Trp Trp Gly Asp Met Glu Lys Asn Gly Asp Gln Gln Phe Asp Phe Ser

85 90 95

Tyr Ala Gln Arg Phe Ala Gln Ala Ala Arg Asn Ala Gly Ile Lys Ile

100 105 110

Val Pro Ile Ile Ser Thr His Gln Cys Gly Gly Asn Val Gly Asp Asp

115 120 125

Cys Asn Val Pro Leu Pro Gln Trp Val Trp Asn Leu Lys Ser Asp Asp

130 135 140

Ser Leu Tyr Phe Lys Ser Glu Thr Gly Thr Thr Asn Lys Glu Thr Leu

145 150 155 160

Ser Pro Leu Ala Thr Asp Val Ile Ser Lys Gln Tyr Gly Glu Leu Tyr

165 170 175

Thr Ala Phe Ala Gln Ala Leu Ala Pro Tyr Lys Asp Val Ile Ala Lys

180 185 190

Ile Tyr Leu Ser Gly Gly Pro Ala Gly Glu Ile Arg Tyr Pro Ser Tyr

195 200 205

Thr Ala Ala Asp Gly Thr Gly Tyr Pro Ser Arg Gly Lys Phe Gln Val

210 215 220

Tyr Thr Asn Phe Ala Lys Ser Lys Phe Gln Ser Tyr Ala Leu Thr Lys

225 230 235 240

Tyr Gly Ser Leu Ala Gly Val Asn Gln Ala Trp Gly Thr Asn Leu Thr

245 250 255

Ser Ala Ser Gln Ile Leu Pro Pro Ser Asp Gly Tyr Gln Phe Leu Lys

260 265 270

Asp Gly Tyr Ser Thr Ala Tyr Gly Lys Asp Phe Leu Ala Trp Tyr Gln

275 280 285

Gly Ala Leu Glu Asp His Thr Lys Arg Ile Gly Gln Leu Ala His Gln

290 295 300

Ala Phe Asp Ala Thr Phe Asn Val Pro Ile Gly Ala Lys Val Ala Gly

305 310 315 320

Ile His Trp Gln Tyr Asn Asn Pro Thr Ile Pro His Ala Ala Glu Lys

325 330 335

Pro Ala Gly Tyr Asn Asp Tyr Asn Ala Leu Leu Asp Ala Phe Lys Thr

340 345 350

Ala Lys Leu Asp Ile Thr Phe Thr Cys Leu Glu Met Thr Asp Ser Gly

355 360 365

Ser Tyr Pro Glu Tyr Ser Met Pro Lys Thr Leu Val Arg Gln Val Ala

370 375 380

Gly Ile Ala Asn Ala Lys Gly Ile Val Leu Asn Gly Glu Asn Ala Leu

385 390 395 400

Thr Ile Gly Ser Glu Asp Gln Tyr Lys Lys Ala Ala Glu Met Ala Phe

405 410 415

Asn Tyr Asn Phe Ala Gly Phe Thr Leu Leu Arg Phe Tyr Asp Val Ile

420 425 430

Asn Asn Asp Thr Leu Met Gly Gln Phe Lys Asn Thr Leu Gly Val Thr

435 440 445

Pro Val Ala Gln Thr Val Val Val Lys Asn Ala Pro Thr Ala Val Gly

450 455 460

Glu Thr Val Tyr Ile Val Gly Asp Arg Ala Glu Leu Gly Gln Trp Asp

465 470 475 480

Thr Ser Leu Tyr Pro Ile Lys Leu Thr Tyr Asn Ser Ser Thr Ala Asp

485 490 495

Trp Arg Gly Thr Val Tyr Phe Pro Ala Ser Gln Asn Val Gln Phe Lys

500 505 510

Ala Ile Val Lys Arg Ala Asp Gly Ser Leu Lys Ala Trp Gln Pro Ser

515 520 525

Gln Gln Tyr Trp Ser Val Pro Ser Thr Thr Ala Thr Tyr Thr Asp Asn

530 535 540

Trp

545

<210> 2

<211> 1638

<212> DNA

<213>artificial sequence

<400> 2

atgaaacagc tatgtaaaaa aggattggct tttattttgg tactcatttt tgttaacgct 60

ttcattttga atccacttaa tggagcggct gccgtagatg gaaaatcaat gaatcctggt 120

tacaaaacct acttaatggc gcctttaaaa aaggtaacag actatacaac atgggaagcg 180

tttgagaacg atttacgcaa agcgaaacaa aatggatttt atgcggtgac agtagacttc 240

tggtggggag atatggagaa gaacggcgat cagcagtttg atttttccta tgctcagcgc 300

tttgctcaag ctgctcgtaa tgcaggtata aagatcgttc ctattatttc tactcatcag 360

tgcggcggta atgttggaga tgattgtaac gttccgcttc cgcagtgggt atggaactta 420

aaaagtgatg acagccttta ctttaaatct gaaacaggta cgacaaataa agaaacgcta 480

agcccgcttg caactgacgt tatttctaag caatacggag agctctatac ggcatttgcg 540

caagcgttag caccttataa agacgtgatt gctaaaatct atttatccgg aggccctgca 600

ggtgaaattc gttatccatc ctatacagca gcagacggaa ccggctatcc gtctagagga 660

aaatttcaag tgtatacgaa cttcgccaaa agcaagtttc aatcatatgc tttgactaaa 720

tacggttcac tcgccggcgt caatcaggca tggggaacca atttaacctc tgcatcgcaa 780

attttaccgc catcagatgg ctatcagttc ttaaaagatg gttattcaac agcttatgga 840

aaagatttct tagcatggta tcaaggagct ttggaagatc acacaaaacg tattggacag 900

ttagctcatc aggcttttga tgccaccttt aacgtaccaa tcggtgcaaa agtggcggga 960

attcattggc agtacaataa tccgacgatt cctcatgctg cagaaaaacc tgctggatat 1020

aatgattaca atgcgctttt agacgctttt aaaacagcta aattagatat aacgtttacg 1080

tgcttagaaa tgacggacag cggaagttat cccgaatatt ctatgccaaa gacgcttgta 1140

cgccaagtag caggtattgc gaatgcaaaa ggaattgttt taaacgggga aaatgctcta 1200

actataggca gtgaagatca atataaaaaa gcagctgaaa tggcctttaa ctataatttt 1260

gcaggattta ctttgcttcg gttctacgat gtcattaaca atgatacgct gatggggcaa 1320

tttaaaaata cgctgggcgt tacaccagtt gcgcaaacgg ttgtagtaaa aaatgcgcca 1380

actgcggtag gagaaacggt ttatattgtt ggagacagag ctgagctagg tcagtgggat 1440

acgtcccttt atccaattaa attaacatat aattcatcta cagccgattg gagaggcact 1500

gtctattttc ctgcgagtca aaatgttcaa tttaaagcaa ttgtgaagag agctgatggc 1560

tcgttaaaag catggcagcc ttcgcagcaa tattggagcg tgccgtcaac aacagcaact 1620

tatacagata attggtaa 1638

<210> 3

<211> 1701

<212> DNA

<213>artificial sequence

<400> 3

atgaaacagc tatgtaaaaa aggattggct tttattttgg tactcatttt tgttaacgct 60

ttcattttga atccacttaa tggagcggct gccgtagatg gaaaatcaat gaatcctggt 120

tacaaaacct acttaatggc gcctttaaaa aaggtaacag actatacaac atgggaagcg 180

tttgagaacg atttacgcaa agcgaaacaa aatggatttt atgcggtgac agtagacttc 240

tggtggggag atatggagaa gaacggcgat cagcagtttg atttttccta tgctcagcgc 300

tttgctcaag ctgctcgtaa tgcaggtata aagatcgttc ctattatttc tactcatcag 360

tgcggcggta atgttggaga tgattgtaac gttccgcttc cgccttgggt atggaactta 420

aaaagtgatg acagccttta ctttaaatct gaaacaggta cgacaaataa agaaacgcta 480

agcccgcttg caactgacgt tatttctaag caatacggag agctctatac ggcatttgcg 540

caagcgttag caccttataa agacgtgatt gctaaaatct atttatccgg aggccctgca 600

ggtgaaattc gttatccatc ctatacagca gcagacggaa ccggctatcc gtctagagga 660

aaatttcaag tgtatacgaa cttcgccaaa agcaagtttc aatcatatgc tttgactaaa 720

tacggttcac tcgccggcgt caatcaggca tggggaacca atttaacctc tgcatcgcaa 780

attttaccgc catcagatgg ctatcagttc ttaaaagatg gttattcaac agcttatgga 840

aaagatttct tagcatggta tcaaggagct ttggaagatc acacaaaacg tattggacag 900

ttagctcatc aggcttttga tgccaccttt aacgtaccaa tcggtgcaaa agtggcggga 960

attcattggc agtacaataa tccgacgatt cctcatgctg cagaaaaacc tgctggatat 1020

aatgattaca atgcgctttt agacgctttt aaaacagcta aattagatat aacgtttacg 1080

tgcttagaaa tgacggacag cggaagttat cccgaatatt ctatgccaaa gacgcttgta 1140

cgccaagtag caggtattgc gaatgcaaaa ggaattgttt taaacgggga aaatgctcta 1200

actataggca gtgaagatca atataaaaaa gcagctgaaa tggcctttaa ctataatttt 1260

gcaggattta ctttgcttcg gttctacgat gtcattaaca atgatacgct gatggggcaa 1320

tttaaaaata cgctgggcgt tacaccagtt gcgcaaacgg ttgtagtaaa aaatgcgcca 1380

actgcggtag gagaaacggt ttatattgtt ggagacagag ctgagctagg tcagtgggat 1440

acgtcccttt atccaattaa attaacatat aattcatcta cagccgattg gagaggcact 1500

gtctattttc ctgcgagtca aaatgttcaa tttaaagcaa ttgtgaagag agctgatggc 1560

tcgttaaaag catggcagcc ttcgcagcaa tattggagcg tgccgtcaac aacagcaact 1620

tatacagata attggtgtgg atcaaaggtg aatgcagaga tgaatatacc gctgtcgacg 1680

tgggtgtggg atacaaagta g 1701

<210> 4

<211> 1701

<212> DNA

<213>artificial sequence

<400> 4

atgaaacagc tatgtaaaaa aggattggct tttattttgg tactcatttt tgttaacgct 60

ttcattttga atccacttaa tggagcggct tccgtagatg gaaaatcaat gaatcctggt 120

tacaaaacct acttaatggc gcctttaaaa aaggtaacag actatacaac atgggaagcg 180

tttgagaacg atttacgcaa agcgaaacaa aatggatttt atgcggtgac agtagacttc 240

tggtggggag atatggagaa gaacggcgat cagcagtttg atttttccta tgctcagcgc 300

tttgctcaag ctgctcgtaa tgcaggtata aagatcgttc ctattatttc tactcatcag 360

tgcggcggta atgttggaga tgattgtaac gttccgcttc cgtcttgggt atggaactta 420

aaaagtgatg acagccttta ctttaaatcg gaaacaggta cgacaaataa agaaacgcta 480

agcccgcttg caactgacgt tatttctaag caatacggag agctctatac ggcatttgcg 540

caagcgttag caccttataa agacgtgatt gctaaaatct atttatccgg aggccctgca 600

ggtgaaattc gttatccgtc ctatacagca gcagacggaa ccggctatcc gtctagagga 660

aaatttcaag tgtatacgaa cttcgccaaa agcaagtttc aatcatatgc tttgactaaa 720

tacggttcac tcgccggcgt caatcaggca tggggaacca atttaacctc tgcatcgcaa 780

attttaccgc catcagatgg ctatcagttc ttaaaagatg gttattcaac agcttatgga 840

aaagatttct tagcatggta tcaaggagct ttggaagatc acacaaaacg tattggacag 900

ttagctcatc aggcttttga tgccaccttt aacgtaccaa tcggtgcaaa agtggcggga 960

attcattggc agtataataa tccgacgatt cctcatgctg cagaaaaacc tgctggatat 1020

aatgattaca atgcgctttt agacgctttt aaaacagcta aattagatat aacgtttacg 1080

tgcttagaaa tgacggacag cggaagttat cccgaatatt ctatgccaaa gacgcttgta 1140

cgccaagtag caggtattgc gaatgcaaaa ggaattgttt taaacgggga aaatgctcta 1200

actataggca gtgaagatca atataaaaaa gcagctgaaa tggcctttaa ctataatttt 1260

gcaggattta ctttgcttcg tttctacgat gtcattaaca atgatacgct gatggggcaa 1320

tttaaaaata cgctggccgt tacaccagtt gcgcaaacgg ttgtagtaaa aaatgcgcca 1380

actgcggtag gagaaacggt ttatattgtt ggagacagag ctgagctagg tcagtgggat 1440

acgtcccttt atccaattaa attaacatat aattcatcta cagccgattg gagaggcacc 1500

gtctattttc ctgcgagtca aaatgttcaa tttaaagcaa ttgtgaagag agctgatggc 1560

tcgttaaaag catggcagcc ttcgcagcaa tattggagcg tgccgtcaac aacagcaact 1620

tatacagata attggtgtgg atcaaaggtg aatgcagaga tgaatatacc gctgtcgacg 1680

tgggtgtggg atacaaagta g 1701

<210> 5

<211> 1701

<212> DNA

<213>artificial sequence

<400> 5

atgaaacagc tatgtaaaaa agggttggct tttattttgg tgctcatttt tgttaacgct 60

ttcattttga atccacttaa tggagcggct gccgtagatg gaaaatcaat gaatcctggt 120

tacaaaacct acttaatggc gcctttaaaa aaggtaacag actatacaac atgggaagcg 180

tttgagaacg atttacgcaa agcgaaacaa aatggatttt atgcggtgac agtagacttc 240

tggtggggag atatggagaa gaacggcgat cagcagtttg atttttccta tgctcagcgc 300

tttgctcaag ctgctcgtaa tgcaggtata aagatcgttc ctattatttc tactcatcag 360

tgcggcggta atgttggaga tgattgtaac gttccgcttc cgtcttgggt atggaactta 420

aaaagtgatg acagccttta ctttaaatcg gaaacaggta cgacaaataa agaaacgcta 480

agcccgcttg caactgacgt tatttctaag caatacggag agctctatac ggcatttgcg 540

caagcgttag caccttataa agacgtgatt gctaaaatct atttatccgg aggccctgca 600

ggtgaaattc gttatccgtc ctatacagca gcagacggaa ccggctatcc gtctagagga 660

aaatttcaag tgtatacgaa cttcgccaaa agcaagtttc aatcatatgc tttgactaaa 720

tacggttcac tcgccggcgt caatcaggca tggggaacca atttagcctc tgcatcgcaa 780

attttaccgc catcagatgg ctatcagttc ttaaaagatg gttattcaac agcttatgga 840

aaagatttct tagcatggta tcaaggagct ttggaagatc acacaaaacg tattggacag 900

ttagctcatc aggcttttga tgccaccttt aacgtaccaa tcggtgcaaa agtggcggga 960

attcattggc agtataataa tccgacgatt cctcatgctg cagaaaaacc tgctggatat 1020

aatgattaca atgcgctttt agacgctttt aaaacagcta aattagatat aacgtttacg 1080

tgcttagaaa tgacggacag cggaagttat cccgaatatt ctatgccaaa gacgcttgta 1140

cgccaagtag caggtattgc gaatgcaaaa ggaattgttt taaacgggga aaatgctcta 1200

actataggca gtgaagatca atataaaaaa gcagctgaaa tggcctttaa ctataatttt 1260

gcaggattta ctttgcttcg tttctacgat gtcattaaca atgatacgct gatggggcaa 1320

tttaaaaata cgctggccgt tacaccagtt gcgcaaacgg ttgtagtaaa aaatgcgcca 1380

actgcggtag gagaaacggt ttatattgtt ggagacagag ctgagctagg tcagtgggat 1440

acgtcccttt atccaattaa attaacatat aattcatcta cagccgattg gagaggcacc 1500

gtctattttc ctgcgagtca aaatgttcaa tttaaagcaa ttgtgaagag agctgatggc 1560

tcgttaaaag catggcagcc ttcgcagcaa tattggagcg tgccgtcaaa aacagcaact 1620

tatacagata attggtgtgg atcaaaggtg aatgcagaga tgaatatacc gctgtcgacg 1680

tgggtgtggg atacaaagta g 1701

<210> 6

<211> 1701

<212> DNA

<213>artificial sequence

<400> 6

atgaaacagc tatgtaaaaa aggattggct ttcgttttga tgttcatttt tgttaacgct 60

ttcatttcaa gtccaattaa cggagcggct gccgtagatg gaaaatcaat gaatccaggt 120

tacaaaacct atttaatggc gcctttaaaa aaggtaacag actatacaac atgggaagcg 180

tttgagaacg atttacgcaa agcgaaacaa aatggatttt atgcagtgac agtagacttc 240

tggtggggag atatggagaa aaacggtgat cagcagttcg atttttccta tgctcagcga 300

tttgctcaag cagctcgtaa cgcgggtata aagatcgttc ctattatttc tactcatcag 360

tgcggcggta atgtaggaga tgattgtaac gttccgcttc cgtcttgggt atggaactta 420

aaaagtgatg acagccttta ctttaaatct gaaacaggta cgacaaataa agaaacgcta 480

agcccgcttg caaccgacgt tatttctaag caatacggag agctctatac ggcatttgcg 540

caagcgttag caccttataa agacgtgatt gctaaaatct atttatcagg aggccctgca 600

ggtgaaattc gttatccgtc ttatacagca gcagacggaa ccggctatcc gtctagaggg 660

aaatttcaag tgtatacgaa cttcgccaaa agcaagtttc aatcatatgc tttgactaaa 720

tacggttcac tcgccggcat taatcaagca tggggaacca atttaacgtc tgcatcgcaa 780

attttaccgc catcagatgg ctatcagttc ttaaaagatg gttattcaac agcttatgga 840

aaagatttct tagcatggta tcaaggagct ttggaagatc acacaaaacg tattggacag 900

ttagctcatc aggcttttga ttccaccttt aacgtaccaa tcggtgcaaa agtggcagga 960

attcattggc agtataataa tcccacgatt cctcatgctg cagaaaaacc tgctggatat 1020

aatgattaca acgcgctttt agatgcgttt aaaacagcta aattagatat aacgtttacg 1080

tgcttagaaa tgacggacag cggaaattat ccggaatatt ctatgccaaa gacgcttgta 1140

cgccaggtag caggtattgc gaatgcaaaa ggagttgttt taaacgggga aaatgcttta 1200

actataggca gtgaagatca atataaaaaa gcagctgaaa tggcctttaa ctataatttt 1260

gcaggattta ctttgcttcg tttctacgat gttattaaca atgatacgct gatggggcaa 1320

tttaaaaata cgttgggcgt tacacctgtt gcgcaaacgg ttgtagtaaa aaatgcgcca 1380

actgcattag gagaaacggt ttatattgtt ggagacagag ctgagctagg tcagtgggat 1440

acgtccattt atccaattaa attaacatat aattcatcta cagctgattg gagaggcacc 1500

gtctattttc ctgcgagtca aaatgttcaa tttaaagcaa ttgtgaagag agctgatgga 1560

tcgttaaaag catggcagcc ttcgcagcaa tattggagcg tgccgtcaac aacaacgact 1620

tatacagata attggtgtgg atcaaatgtg aatgcagaga tgaatatacc gctgtcgacg 1680

tgggtgtggg atacaaagta g 1701

<210> 7

<211> 1701

<212> DNA

<213>artificial sequence

<400> 7

atgaaacagc tatgtaaaaa aggattggct ttcgttttga tgttcatttt tgttaacgct 60

ttcattttaa gtccaattaa cggagcggct gccgtagatg gaaaatcaat gaatccaggt 120

tacaaaacct atttaatggc gcctttaaaa aaggtaacag actatacaac atgggaagcg 180

tttgagaacg atttacgcaa agcgaaacaa aatggatttt atgcagtgac agtagacttc 240

tggtggggag atatggagaa aaacggcgat cagcagttcg atttttccta tgctcagcga 300

tttgctcaag cagctcgtaa cgcgggtata aagatcgttc ctattatttc tactcatcag 360

tgcggcggta atgtaggaga tgattgtaac gttccgcttc cgtcttgggt atggaactta 420

aaaagtgatg acagccttta ctttaaatct gaaacaggta cgacaaataa agaaacgcta 480

agcccgcttg caaccgacgt tatttctaag caatacggag agctctatac ggcatttgcg 540

caagcgttag caccttataa agacgtgatt gctaaaatct atttatcagg aggccctgca 600

ggtgaaattc gttatccgtc ttatacagca gcagacggaa ccggctatcc gtctagaggg 660

aaatttcaag tgtatacgaa cttcgccaaa agcaagtttc aatcatatgc tttgactaaa 720

tacggttcac tcgccggcat taatcaagca tggggaacca atttaacgtc tgcatcgcaa 780

attttaccgc catcagatgg ctatcagttc ttaaaagatg gttattcaac agcttatgga 840

aaagatttct tagcatggta tcaaggagct ttggaagatc acacaaaacg tattggacag 900

ttagctcatc aggcttttga ttccaccttt aacgtaccaa tcggtgcaaa agtggcagga 960

attcattggc agtataataa tcccacgatt cctcatgctg cagaaaaacc tgctggatat 1020

aatgattaca acgcgctttt agatgcgttt aaaacagcta aattagatat aacgtttacg 1080

tgcttagaaa tgacggacag cggaaattat ccggaatatt ctatgccaaa gacgcttgta 1140

cgccaggtag caggtattgc gaatgcaaaa ggagttgttt taaacgggga aaatgcttta 1200

actataggca gtgaagatca atataaaaaa gcagctgaaa tggcctttaa ctataatttt 1260

gcaggattta ctttgcttcg tttctacgat gttgttaaca atgatacgct gatggggcaa 1320

tttaaaaata cgttgggcgt tacaccactt gcgcaaacgg ttgtagtaaa aaatgcgcca 1380

actgcattag gagaaacggt ttatattgtt ggagacagag ctgagctagg tcagtgggat 1440

acgtccattt atccaattaa attaacatat aattcatcta cagctgattg gagaggcacc 1500

gtctattttc ctgcgagtca aaatgttcaa tttaaagcaa ttgtgaagag agctgatgga 1560

tcgttaaaag catggcagcc ttcgcagcaa tattggagcg tgccgtcaac aacaacgact 1620

tatacagata attggtgtgg atcaaatgtg aatgcggaga tgaatatacc gctgtcgacg 1680

tgggtgtggg atacaaagta g 1701

Claims

1. a kind of beta amylase, which is characterized in that the beta amylase are as follows:

(a) protein that the amino acid sequence shown in SEQ ID No.1 forms；Alternatively,

(b) amino acid sequence in (a) is by replacing, missing or adding one or several amino acid and having beta amylase living The protein as derived from (a) of property.

2. encoding the gene of beta amylase described in claim 1.

3. gene as claimed in claim 2, which is characterized in that the nucleotide sequence of the gene is as shown in SEQ ID No.2.

4. carrying the recombinant plasmid of gene described in Claims 2 or 3.

5. recombinant plasmid as claimed in claim 4, which is characterized in that the carrier of the recombinant plasmid is pET carrier, pUC load Body, pT7-7 carrier or pGEX carrier.

6. carrying the host cell of gene described in Claims 2 or 3 or the recombinant plasmid of claim 4 or 5.

7. host cell as claimed in claim 6, which is characterized in that the host cell is bacterium or fungi.

8. the preparation method of beta amylase described in claim 1, which is characterized in that by host cell described in claim 6 or 7 It is seeded in fermentation medium and ferments.

9. gene described in beta amylase or Claims 2 or 3 described in claim 1 or the recombinant plasmid of claim 4 or 5 or Application of the preparation method described in the host cell of claim 6 or 7 or claim 8 in terms of producing maltose.

10. a kind of method for producing maltose, which is characterized in that by beta amylase described in claim 1 or claim 5 or 6 The beta amylase being prepared described in the host cell or claim 8 is added in starch and/or dextrin and is digested.