Optimization for the maximum bacteriocin production of Lactobacillus brevis DF01 using response surface methodology

To enhance the production of bacteriocin DF01, produced by Lactobacillus brevis DF01, cultivation conditions and medium composition were optimized by using response surface methodology (RSM). The selected 5 factors based on MRS medium were glucose, yeast extract, MgSO₄, temperature, and initial pH. Fractional factorial design (FFD) was effective in searching for the main factors. By a 2^5?1 FFD, glucose, yeast extract, and initial pH were found to be significant factors and had positive effects on bacteriocin production. The effects of the 3 main factors on bacteriocin production were further investigated by a central composite design (CCD). RSM revealed that the maximum bacteriocin production was achieved at yeast extract concentration of 14.56 g/L, glucose concentration of 28.95 g/L, and initial pH of 6.8. After RSM, the titer of bacteriocin was increased by 4-fold.     

响应面法优化茯苓多糖发酵培养基

以茯苓菌种为研究对象,采用响应面法对其产茯苓粗多糖的发酵培养基组分进行优化。 在单因素优化的基础上,利用Plackett- Burman（PB）试验设计筛选出影响茯苓粗多糖产量的3个显著性因素：葡萄糖、酵母粉、硫酸镁。 利用响应面分析法（RSM）优化,得到 最佳培养基组分为：葡萄糖47.1 g/L、酵母粉20.5 g/L、硫酸镁1.8 g/L、蛋白胨30 g/L、硝酸钠5 g/L、磷酸二氢钾1.0 g/L、VB1 1 g/L、无水氯 化钙0.1 g/L。 在此优化条件下,茯苓粗多糖产量为138 mg/100 mL,是优化前的1.3倍。     

枯草芽孢杆菌ZJS18发酵生产γ-聚谷氨酸培养条件的优化

通过响应面法对枯草芽孢杆菌ZJS18发酵生产γ-聚谷氨酸的培养条件进行优化。首先采用Plackett-Burman试验设计筛选出对γ-聚谷氨酸产量有显著影响的3?个关键因素,即蔗糖、酵母粉和谷氨酸钠;然后通过Box-Behnken试验设计和响应面法对这3?个关键因素的用量进行优化。响应面优化后的3?个关键因素的最佳质量浓度为蔗糖64.40?g/L、酵母粉7.10?g/L和谷氨酸钠57.96?g/L。枯草芽孢杆菌ZJS18发酵生产γ-聚谷氨酸的最佳培养条件为蔗糖用量64.40?g/L、酵母粉用量7.10?g/L、谷氨酸钠用量57.96?g/L,氯化钠用量30?g/L,MgSO4用量0.3?g/L、K2HPO4用量2?g/L,初始pH?7.5,接种量5%,装液量40?mL/250?mL,温度37?℃,摇床转速200?r/min,发酵时间36?h。在上述条件下,γ-聚谷氨酸产量为13.20?g/L。与未优化前相比,产量提高了1.88?倍。     

Statistical Optimization of Culture Components for Enhanced Bacteriocin Production by Lactobacillus plantarum LR/14

Statistical optimization of bacteriocin production by a natural isolate of Lactobacillus plantarum LR/14 was carried out in TGYE medium at 37°C and 200 rpm for 20h. In the first step of optimization using Plackett-Burman design, yeast extract, glucose and incubation period were identified as the most important factors for bacteriocin production. These factors were further optimized by response surface methodology (RSM) to understand their interaction and to determine their optimal levels. Results indicated that the maximum bacteriocin production was achieved in a medium containing glucose 2.0% and yeast extract 2.5%, and after an incubation period of 20h. An overall approximatley eightfold improvement in bacteriocin production was achieved as a result of optimization. These results indicated the importance of statistical tools in designing culture conditions for enhancing the production of bacteriocin from L. plantarum LR/14. Such an improved production will facilitate the application of bacteriocin, especially in food preservation.     

Optimization of medium on exopolysaccharides production in submerged culture of Cordyceps militaris

Statistical experimental design strategy (SES) was applied to optimize the medium for the exopolysaccharides (EPS) production of Cordyceps militaris by submerged culture in shaker flask. A significant influence of the glucose and peptone on the EPS production was first evaluated by using a Plackett-Buman design. Then, steepest ascent method was employed to approach the experimental design space. Last, these factors were further optimized using central composite design (CCD) and response surface methodology (RSM). A quadratic model was found to fit the EPS production. The optimum values of the tested variables for the production of EPS were 48.67 g/L glucose, 12.56 g/L peptone, 1 g/L KH₂PO₄, 10 g/L yeast extract, and 0.5 g/L MgSO₄·7H₂O. Under optimization of culture conditions, the EPS production was enhanced from 0.78 to 1.96 g/L. In comparison with that of original culture conditions, 2.5 fold increase was obtained.     

响应面法优化海洋细菌Bacillus sp.YP07淀粉酶发酵条件研究

从海南洋浦近海分离到1株产淀粉酶的海洋细菌Bacillus sp.G23,利用Plackett-Burman设计对发酵条件进行了筛选,结果表明,蛋白胨、酵母粉和NaCl浓度对酶产量具有显著的影响;利用响应面法对3个因子进行了优化,获得了最佳发酵条件:可溶性淀粉5.00g/L,蛋白胨3.88g/L,酵母粉3.97g/L,NaCl 37.69g/L,pH7.0,180r/min、35℃培养48h,酶产量为665.4U/mL,较初始酶产量提高了4.3倍.     

Medium Optimization of Gamma Linolenic Acid Production in Mucor rouxii CFR -G15 using RSM

Omega-6 polyunsaturated fatty acids has both pharmaceutical and neutraceutical importance. Central composite rotatable design (CCRD), along with response surface methodology (RSM), was employed to optimize the medium components for maximum production of gamma linolenic acid (GLA) from Mucor rouxii CFR-G15. Nutritional parameter such as carbon (glucose) and nitrogen (yeast extract and ammonium nitrate) sources were focused in this study to enhance the GLA production. The optimal conditions for maximizing GLA production (18.55%) were at 65 g glucose per liter; 3.5 g yeast extract per liter, and 0.5 g ammonium nitrate per liter. Thus, by using CCRD with RSM, it is quite possible to determine the accurate values of the fermentation parameters where maximum production of GLA is achieved.     

Optimization of culture medium and conditions for Neo-fructooligosaccharides production by <Emphasis Type="Italic">Penicillium citrinum</Emphasis>

Culture medium and conditions were optimized to improve neo-fructooilgosaccharide (neo-FOS) production by Penicillium citrinum using Response Surface Methodology (RSM). The central composite designs using RSM were employed in this investigation. The quadratic models for neo-FOS production were obtained. Among culture media, optimal concentration of sucrose and yeast extract were found to be 12.65% and 2.90%, respectively, and predicted maximum value of neo-FOS production was 39.3 g/l. For culture conditions, optimal points of inoculum age (78.5 h), initial pH (7.34) and inoculum size (11.36% (v/v)) were determined and predicted maximum value of neo-FOS production was 40.6 g/l. By performing the culture under optimal culture media and conditions, actual neo-FOS production increased to 107%. It was also suggested that RSM can be used as a potential tool for optimization of factors in fermentation and food industry.     

乳酸乳球菌生产γ-氨基丁酸条件的优化

采用析因设计和中心组合试验设计对乳酸乳球菌FJNU-GA1304产γ-氨基丁酸(γ-aminobutyric acid,GABA)的条件进行优化。完全析因设计优化后的细胞转化条件为:p H 3.5、反应温度40℃、反应时间24 h,谷氨酸钠质量浓度20 g/L和湿菌体质量浓度25 g/L;在单因素试验的基础上,通过筛选设计确定谷氨酸钠、玉米浆粉和葡萄糖质量浓度为主效因子。采用三因素三水平的中心组合试验对主效因子的交互作用进行分析,结果表明:最佳的培养基组成为谷氨酸钠9.50 g/L、玉米浆粉12.50 g/L、葡萄糖5.74 g/L、酵母膏5.00 g/L、K2HPO4 1.20 g/L、Mg SO4 0.60 g/L。在最佳转化条件和发酵培养基组合下,GABA产量最高达9.06 g/L,比优化前4.80 g/L提高了88.8%。     

Actinobacillus succinogenes NJ113厌氧发酵产丁二酸培养条件的优化

采用Plackett-Burman设计法(Plackett-Burman,PB),对影响Actinobacillus succinogenes NJ113厌氧发酵生产丁二酸的11个因子进行了筛选。结果表明,影响该菌厌氧发酵产丁二酸的主要因子为葡萄糖、酵母膏、玉米浆。在此基础上,采用响应曲面法(Response Surface Methodology,RSM)对这3个因子的影响进行了研究,得出丁二酸产量的数学模型,通过对二次多项回归方程求解,得到3因子的最优用量:葡萄糖107g/L,酵母膏16 g/L,玉米浆12 g/L,在优化条件下培养48 h,丁二酸的产量由原始培养条件下的62g/L增到84 g/L,收率从62%提高到78.5%,生产强度达1.75 g/(L·h)。     

重组乳酸克鲁维酵母产磷脂酶A2发酵条件的优化

利用重组乳酸克鲁维酵母（Kluyveromyces lactis）GG799表达磷脂酶A2,对其产酶发酵条件进行研究。采用单因素试验和正交试验对培养基及培养条件进行优化,确定了重组菌产酶的最佳发酵条件。结果表明：最优培养基组成为葡萄糖30 g/L、酵母粉20 g/L、蛋白胨30 g/L、KH2PO4 3 g/L;最优培养条件为：发酵温度30 ℃、接种量2%（V/V）、初始pH?7.0、装液量90 mL/250 mL三角瓶、摇床转速220 r/min,在此条件下发酵培养,酶活力由（1.87±0.12）U提高到（5.35±0.27）U。     

响应曲面法优化短双歧杆菌Bifidobacterium breve A04培养基

本文通过响应曲面法(RSM)达到优化双歧杆菌培养基组分的目的。以TPYG培养基为基础培养基,采用FFD(factionalfactorialdesign)实验设计法,筛选出三种最佳生长强化因子葡萄糖、酵母粉和初始pH值;通过快速登高法摸索出生长强化因子的最佳浓度范围为:葡萄糖5.0g/L,酵母膏3.01g/L以及初始pH6.0;利用旋转中心组分设计法(RCD)和响应曲面法(RSM)确定关键组分的最佳浓度并进行了验证。最终优化培养基组分为葡萄糖5.194g/L,酵母膏2.829g/L,低聚果糖2g/L,西红柿汁50ml,肝浸液5g/L,Tween801ml,半胱氨酸盐酸盐0.3g/L,pH6.463。最终优化出的培养基获得的菌体干重达到4.462g/L,比优化前3.16g/L提高了1.43倍。     

黑曲霉SFGT601产葡萄糖酸钠发酵培养基及工艺条件的研究

以一株耐高温、耐高糖的葡萄糖酸钠生产菌株Aspergillus niger SFGT601为研究对象,在前期研究工作的基础上,首先利用5 L发酵罐对其发酵培养基组成进行了优化,得到了理想的培养基组成为葡萄糖320 g/L,玉米浆3.5 g/L,酵母膏2.0 g/L,硫酸镁1.5 g/L,然后进一步考察了pH值和溶解氧对其发酵的影响,确定了最佳的pH和溶解氧控制策略为溶解氧20%,0～8 h控制pH值5.5～6.0,8～22 h控制pH值5.0～5.5。在此最佳工艺条件下菌株SFGT601的葡萄糖酸钠产量提高到326.0 g/L。     

锁掷孢酵母产胞外多糖发酵条件优化

为进一步提高酵母菌产酵母胞外多糖（EPS）的能力,该研究以近粉红锁掷孢酵母（Sporidiobolus pararoseus）PFY-Z1为出发菌株,筛选出其最适产糖发酵培养基,并以此为基础,联合应用单因素试验、Plackett-Burman（PB）试验和中心组合设计（CCD）试验,优化菌株产EPS的最佳发酵条件。结果表明,菌株最佳培养基配方为葡萄糖15 g/L,硫酸铵15 g/L,硫酸镁1.8 g/L,氯化钙0.28 g/L,磷酸氢二钾0.24 g/L,氯化钠0.6 g/L。菌株最佳培养条件为培养温度28 ℃、摇床转速210 r/min、接种量5%、装液量100 mL/250 mL、培养时间6 d,培养基初始pH值5.10条件下,EPS含量最高,为（4.60±0.13）g/L,是优化前的1.40倍。该研究为今后利用S. pararoseus PFY-Z1产胞外多糖奠定了基础,同时也为酵母菌EPS的工业化制备和生产提供了理论依据。     

Production of malic and succinic acids by sugar-tolerant yeast <Emphasis Type="Italic">Zygosaccharomyces rouxii</Emphasis>

Zygosaccharomyces rouxii V19 was grown in YPG medium (yeast extract, 0.5%, peptone, 1.0%, glucose, 10%). Fermented broth was purified through a series of ion-exchange columns and ODS column and the purified sample was TMS-esterified. Malic and succinic acids were identified with GC-MS analysis. The yeast was cultivated under various cultural conditions and quantitative determination of the organic acids was carried out with HPLC on Shodex column. Glucose concentration of 30%, initial pH 5.0, and 25 °C incubation temperature were the optimum conditions. Inclusion of glutamic, malic, and succinic acid precursors in the medium increased the production of malic acid. On the other hand, only addition of malic acid enhanced the production of succinic acid. Maximum amount of malic acid produced was 74.9 g/L (32.8% yield, based on glucose consumption) in the medium with 0.5% glutamic acid supplement, and that of succinic acid was 7.7 g/L (8.1% yield) when 0.3% malic acid was added in the medium.     

鞘氨醇单胞菌产3-苯氧基苯甲酸降解酶发酵条件的优化

以鞘氨醇单胞菌（Sphingomonas sp.）SC-1产3-苯氧基苯甲酸降解酶的酶活性为响应值,对其产酶条件进行优化。采用Plackett-Burman法对培养基组分和培养条件筛选显著性影响因素,并通过Box-Bohnken设计试验优化产酶条件,得到其最优培养基配方为：蛋白胨0.5 g/L、酵母膏0.5 g/L、葡萄糖0.8 g/L、硫酸镁0.01 g/L、3-苯氧基苯甲酸（3-phenoxybenzoic acid,3-PBA）质量浓度0.1 mg/mL;最优培养条件为：初始pH 8.33、种龄40.0 h、接种量4 mL/100 mL（种子液细胞浓度为108 CFU/mL）、转速180 r/min、温度30 ℃、装液量30 mL（250 mL锥形瓶）、培养时间37.75 h。在此条件下,发酵液酶活力可达1.870 5 mU/ g,比优化前（0.226 9 mU/g）提高8.24 倍。     

Statistical Optimization of Culture Components for Enhanced Bacteriocin Production by Lactobacillus plantarum LR/14

Statistical optimization of bacteriocin production by a natural isolate of Lactobacillus plantarum LR/14 was carried out in TGYE medium at 37°C and 200 rpm for 20h. In the first step of optimization using Plackett-Burman design, yeast extract, glucose and incubation period were identified as the most important factors for bacteriocin production. These factors were further optimized by response surface methodology (RSM) to understand their interaction and to determine their optimal levels. Results indicated that the maximum bacteriocin production was achieved in a medium containing glucose 2.0% and yeast extract 2.5%, and after an incubation period of 20h. An overall approximatley eightfold improvement in bacteriocin production was achieved as a result of optimization. These results indicated the importance of statistical tools in designing culture conditions for enhancing the production of bacteriocin from L. plantarum LR/14. Such an improved production will facilitate the application of bacteriocin, especially in food preservation.     

Optimization of beta-carotene production by Rhodotorula glutinis using high hydrostatic pressure and response surface methodology

ABSTRACT:  Rhodotorula glutinis RG6 was treated by high hydrostatic pressure (HHP) of 300 MPa for 15 min for improving its ability of β-carotene production. After the treatments of 5 repeated cycles, the mutant strain RG6p was obtained, β-carotene production of which reached 10.01 mg/L, increased by 57.89% compared with 6.34 mg/L from parent strain RG6. To optimize the medium for β-carotene fermentation by mutant RG6p, a response surface methodology (RSM) approach was used in conjunction with a factorial design and a central composite design, and the maximum yield of β-carotene (13.43 mg/L), an increase of 34.17% compared to the control, was obtained at a pH 6.7 with an optimum medium (40 mL/250 mL) of yeast extract (4.23 g/L), glucose (12.11 g/L), inoculum (30 mL/L), tomato extract (2.5 mL/L), peanut oil (0.5 mL/L), and (NH₄)₂SO₄ (5 g/L).     

γ-聚谷氨酸生产菌株的鉴定及发酵培养基优化

目的:鉴定一株高产γ-聚谷氨酸(γ-polyglutamic acid,γ-PGA)的菌株,并优化其发酵培养基。方法:以实验室前期诱变筛选出的菌株N-2出发,通过16s rDNA核酸序列分析,对该菌株进行了鉴定;采用单因素实验、响应面设计对菌株的发酵培养基进行优化,最终确定最佳培养基配方。结果:经过16s rDNA序列分析,菌株N-2被鉴定为Bacillus subtilis。通过Plackett-Burman(PB)试验,筛选出3个显著影响γ-PGA产量的因素:葡萄糖、谷氨酸钠和K₂HPO₄·3H₂O;用最陡爬坡试验逼近最大产量区后,利用box-behnken试验获得响应曲面最优解,确定葡萄糖、谷氨酸钠和K₂HPO₄·3H₂O的最佳浓度分别为42.93、44.85、2.39 g/L。经过54 h发酵γ-PGA终产量为28.51 g/L,比优化前提高了34.48%。结论:响应面法试验次数少、周期短,可以快速优化发酵培养基成分,结果可靠,是提高产量的有效途径。     

高生物量富硒产朊假丝酵母培养基优化

对富硒产朊假丝酵母发酵培养基进行优化,获得高生物量富硒酵母。从6种发酵培养基中确定G改良培养基为最佳培养基。利用Plackett-Burman设计法从影响富硒产朊假丝酵母生长的12个因子中筛选出葡萄糖、蛋白胨、KH2PO4、CuSO4添加量这4个关键因子。再利用Box-Behnken试验设计及响应面分析法确定关键因子的最佳水平及交互作用。试验得出各关键因子的最优组合为葡萄糖30 g/L、蛋白胨17 g/L、KH2PO4 6.5 g/L、CuSO4 0.01 g/L。结果表明,培养基优化后酵母生物量为12.01 g/L,有机硒含量为1 337.46 μg/g,谷胱甘肽为134.27 mg/L。将培养基中亚硒酸钠添加量由25 μg/mL提高至30 μg/mL,酵母生物量为11.21 g/L,有机硒为1 673.32 μg/g,谷胱甘肽为126.80 mg/L。