高山被孢霉产花生四烯酸发酵条件的研究

通过一株高山被孢霉M_(20)(Mortierella alpina)产花生四烯酸的摇瓶发酵研究,确定了其最佳发酵培养基组成及最适摇瓶发酵工艺条件。摇瓶实验确定的最佳培养基组成为(g/L):玉米粉水解液葡萄糖150,酵母粉15,KH_2PO_4 3.0,NaNO_3 3.0,MgSO_4·7H_2O 0.5。最佳发酵工艺条件为:初始pH6.5,装液量为50ml/500ml摇瓶,摇床转速150r/min,温度在菌体生长前三天控制在25℃培养,以后调至20℃培养。在此条件下,发酵培养被孢霉的生物量、菌体总油脂及花生四烯酸分别高达35.5g/L、13.2g/L及2.2g/L,在15L及1000L自动机械搅拌罐进行发酵试验,AA产量分别高达1.86g/L及1.70g/L。     

Box-Behnken设计-响应面法优化人参干细胞培养体系

[目的]研究人参形成层干细胞(Cambial Meristematic Cell, CMCs)培养体系的构建及相关工艺优化。[方法]通过Box-Behnken设计-响应面法优化人参CMCs培养相关工艺。[结果]从人参形成层中分离得到人参形成层细胞CMCs,诱导分离的最佳培养条件为：B5+IAA 6 mg/L+IBA 6 mg/L+蔗糖20 g/L+琼脂粉7 g/L+L-抗坏血酸100 mg/L+柠檬酸150 mg/L,诱导率为50.54%;固体增殖的最佳培养条件为：B5+IAA 2.9 mg/L+IBA 2.6 mg/L+NAA 5.9 mg/L+蔗糖20 g/L+L-抗坏血酸100 mg/L+柠檬酸150 mg/L,增殖量为1.01 g;悬浮培养的最佳培养条件为：B5+IAA 5 mg/L+IBA 5 mg/L+NAA 5 mg/L+蔗糖20 g/L+L-抗坏血酸100 mg/L+柠檬酸150 mg/L,pH 6.2,增殖量为3.05 g;均为24.6℃暗培养。[结论]人参CMCs具备干细胞特征，Box-Behnken设计-响应面法适用于人参CMCs培养工艺的优化。     

黑曲霉发酵产橙皮苷酶的工艺优化

目的:对黑曲霉WP124发酵产橙皮苷酶的工艺条件进行优化,旨在为利用酶法改造橙皮苷打下基础.方法:采用摇瓶培养,对培养基的成分和培养条件进行了优化.结果:黑曲霉WP124发酵产橙皮苷酶的最佳培养基组成是:蔗糖30g/L,酵母膏20g/L,磷酸二氢钾3g/L,桔皮粉50g/L;最佳培养条件是:起始pH为5.5,培养温度为30℃,摇瓶转速是180r/min.在上述条件下,经过72h的培养,橙皮苷酶酶活达到1398U/mL.结论:该菌株发酵过程具有较好的工业化应用的前景.     

金针菇菌丝体深层培养工艺研究

在1．8L气升式发酵反应器中,研究了金针菇菌丝体深层培养工艺条件及其特性。结果表明：金针菇菌丝体深层培养可采用玉米、黄豆和糖蜜等廉价原料作主要碳氮源;最适需氧量为1．0—2．0×10^-7mol O₂／ml·min·atm,培养24—72h内,菌丝球生长遵循立方根规律·即x^1/3,=0．786+0．027t。在最佳发酵条件下,摇瓶培养4天,茵丝干重达24．4mg／ml在反应器培养4天,菌丝干重为25．7mg／ml。     

沼泽红假单胞菌富硒发酵条件的研究

通过对沼泽红假单胞菌富硒发酵条件的研究,确定最优的富硒培养方式。采用单一因素变量法,利用微波消解与紫外分光光度法测定沼泽红假单胞菌在不同发酵条件下的生物量变化与富硒效果,确定其最佳培养方式。结果表明,最佳富硒培养条件为:培养温度30℃,环境硒浓度100μg/mL,培养基初始pH为7,硒添加方式应为梯度分次添加,添加时间应为培养周期的第3天、第4天。利用得到的富硒菌种,在最优条件下培养7 d后,测得环境硒浓度下降为10.9μg/mL,硒的转化率为89.1%,菌体富硒量可达到73.54 mg/g(干菌种),其中有机硒含量为97.1%。利用沼泽红假单胞菌生产有机硒具有可行性,富硒菌体可以作为动物饲料添加剂,也可以为人类提供富含有机硒的食品。在以后的实验中,将进一步进行验证和工业化应用。     

响应面法优化氧化胁迫提高透明质酸分子量

本文研究了氧化剂NaClO胁迫培养兽疫链球菌Streptococcuszooepidemicus对透明质酸(HA)分子量的影响。运用响应面分析法优化发酵工艺条件,在单因素实验基础上,采用中心复合法研究了NaClO的加入时间和加入浓度对HA分子量的影响。利用Mintab 16软件分析确定最佳提取工艺,根据实际条件,得到HA最佳的发酵工艺参数为:NaClO加入时间7 h,NaClO加入浓度为0.415 mL/L。HA分子量由178万Da提高到219万Da。     

肺炎链球菌5型发酵工艺的优化

目的:采用正交试验设计方法进行肺炎链球菌5型发酵工艺的研究。方法:根据正交试验设计表L9(34)设计的试验条件组合进行了9次肺炎链球菌5型的发酵,采用70升发酵罐进行发酵工艺的摸索,提取了肺炎链球菌5型荚膜多糖粗糖。结果:最佳的发酵培养条件组合为温度37℃、葡萄糖20克/升、大豆胨15克/升、pH值7.3,最佳的纯化条件组合为冷酚抽提三次、沉核酸乙醇浓度23%、超滤膜孔径50kD、最终沉糖乙醇浓度60%,在此筛选得到的最佳条件下,连续进行了5个批次肺炎链球菌5型的发酵与荚膜多糖提取,荚膜多糖粗糖的平均收率为808.6mg/L,相对标准偏差为3.84%。结论:上述发酵培养条件组合适合用于肺炎多糖疫苗的研究和生产。     

玉米水解糖液体培养灵芝发酵条件的优化

目的：优化液体培养灵芝的发酵条件,提高多糖产量。方法：采用玉米水解糖为主要成分的培养基,通过单因素和正交实验,对赤芝G22菌株液体培养过程中影响多糖产量的发酵温度、摇床转速等工艺条件进行了研究。结果：经极差分析和方差分析确定了多糖高产的最佳发酵条件为：发酵温度27℃、摇床转速170r/min、培养基初始pH值6.5、发酵时间144 h。结论：通过优化液体发酵条件,可显著提高灵芝多糖的产量。在最佳发酵条件下液体培养G22菌株,灵芝总多糖产量由1.851g/L提高到2.439g/L,提高了31.0%。     

绿僵菌无纺布菌条的制作(Ⅰ)液体种子培养条件

研究了金龟子绿僵菌菌株Ma83液体培养最佳营养及环境条件,为无纺布培养提供良好的液体种子.以生物量为指标,通过液体摇瓶试验确定了绿僵菌Ma83菌株液体种子培养参数,对不同的氮源、碳源及其浓度和初始pH进行单因素分析.结果表明,绿僵菌Ma83菌株液体种子培养最佳营养条件为4%黄豆粉,2%白砂糖,0.5%MgSO4·7H2O,0.05g/LKCl,0.1g/L FeSO4·7H2O,1.0g/L KH2PO4,pH6.3～6.5.70L发酵罐培养,干生物量第三天可达35g/L,显著优于筛选前培养基(SDA,28g/L,a=0.05).     

绿僵菌无纺布菌条的制作(I)液体种子培养条件

研究了金龟子绿僵菌菌株M a83液体培养最佳营养及环境条件,为无纺布培养提供良好的液体种子。以生物量为指标,通过液体摇瓶试验确定了绿僵菌M a83菌株液体种子培养参数,对不同的氮源、碳源及其浓度和初始pH进行单因素分析。结果表明,绿僵菌M a83菌株液体种子培养最佳营养条件为4%黄豆粉,2%白砂糖,0.5%MgSO4.7H2O,0.05g/LKC l,0.1g/L FeSO4.7H2O,1.0g/L KH2PO4,pH6.3~6.5。70L发酵罐培养,干生物量第三天可达35g/L,显著优于筛选前培养基(SDA,28g/L,a=0.05)。     

蛋白酶产生菌LN01水解玉米黄粉蛋白的研究

玉米黄粉中含有约质量分数60%的蛋白质,但很难直接应用,必须进行预处理.本文以玉米黄粉为原料,利用蛋白酶产生菌LN01进行液体发酵,分别研究了液体接种量、初始pH、培养温度和培养时间等因素对LN01菌株水解玉米黄粉蛋白的影响.实验结果表明,LN01菌株水解玉米黄粉蛋白的最佳发酵条件为:初始pH值为6.0,液体种子接种量...     

Modeling and optimization in anaerobic bioconversion of complex substrates to acetic and butyric acids

Cheese-processing wastewater was biologically treated to produce short-chain organic acids in laboratory scale continuously stirred tank reactors. A constant inoculum system was used to mimimize the experimental error due to the use of inconsistent inoculum. The inoculum system was operated with dilute cheese-processing wastewater with 5000 mg soluble chemical oxygen demand/L at pH 6.5 and 35 degrees C at 0.5 days hydraulic retention time. Response surface methodology was successfully applied to determine the optimum physiological conditions where the maximum rates of acetic and butyric acid production occurred. These were pH 7.01 at 36.2 degrees C and pH 7.26 at 36.2 degrees C, respectively. The lack of overall predictability for butyric acid production meant that the response surface was much more complicated than that of acetic acid; therefore, a small change in pH or temperature could cause large variations in the response of butyric acid production. (c) 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 54:451-460, 1997.     

Dry-thermophilic anaerobic digestion of organic fraction of the municipal solid waste: focusing on the inoculum sources

The effect of inoculum source on anaerobic thermophilic digestion of separately collected organic fraction of municipal solid wastes (SC_OFMSW) has been studied. Performance of laboratory scale reactors (V: 1.1 L) were evaluated using six different inoculums sources: (1) corn silage (CS); (2) restaurant waste digested mixed with rice hulls (RH_OFMSW); (3) cattle excrement (CATTLE); (4) swine excrement (SWINE); (5) digested sludge (SLUDGE); and (6) SWINE mixed with SLUDGE (1:1) (SWINE/SLUDGE). The SC_OFMSW was separately and collected from university restaurant. The selected conditions were: 25% of inoculum, 30% of total solid and 55 degrees C of temperature, optimum in the thermophilic range. The six inoculum sources showed an initial start-up phase in the range between 2 and 4 days and the initial methane generation began over 10 days operational process. Results indicated that SLUDGE is the best inoculum source for anaerobic thermophilic digestion of the treatment of organic fraction of municipal solid waste at dry conditions (30%TS). Over 60 days operating period, it was confirmed that SLUDGE reactor can achieve 44.0%COD removal efficiency and 43.0%VS removal. In stabilization phase, SLUDGE reactor showed higher volumetric biogas generated of 78.9 mL/day (or 35.6 mLCH(4)/day) reaching a methane yield of 0.53 LCH(4)/gVS. Also, SWINE/SLUDGE and SWINE were good inoculums at these experimental conditions.     

The optimization of Marasmius androsaceus submerged fermentation conditions in five-liter fermentor

Using desirability function, four indexes including mycelium dry weight, intracellular polysaccharide, adenosine and mannitol yield were uniformed into one expected value (Da) which further served as the assessment criteria. In our present study, Plackett–Burman design was applied to evaluate the effects of eight variables including initial pH, rotating speed, culture temperature, inoculum size, ventilation volume, culture time, inoculum age and loading volume on Da value during Marasmius androsaceus submerged fermentation via a five-liter fermentor. Culture time, initial pH and rotating speed were found to influence Da value significantly and were further optimized by Box–Behnken design. Results obtained from Box–Behnken design were analyzed by both response surface regression (Design-Expert.V8.0.6.1 software) and artificial neural network combining the genetic algorithm method (Matlab2012a software). After comparison, the optimum M. androsaceus submerged fermentation conditions via a five-liter fermentor were obtained as follows: initial pH of 6.14, rotating speed of 289.3 rpm, culture time of 6.285 days, culture temperature of 26 °C, inoculum size of 5%, ventilation volume of 200 L/h, inoculum age of 4 days, and loading volume of 3.5 L/5 L. The predicted Da value of the optimum model was 0.4884 and the average experimental Da value was 0.4760. The model possesses well fitness and predictive ability.     

Optimization of methane fermentation from effluent of bio-hydrogen fermentation process using response surface methodology

The individual effects and interactive effects of substrate concentration, ratio of inoculum to substrate, Ca(2+) concentration on the methane yield from the effluent of bio-hydrogen fermentation of food waste were investigated in this study. A central composite design (CCD) and response methodology (RSM) were employed in designing the experiments, in order to determine the optimum conditions for methane fermentation. The experiment results showed that the effects of substrate concentration, ratio of inoculum to substrate, Ca(2+) concentration were statistically significant at 5% level. The interactive effect of substrate concentration and ratio of inoculum to substrate was significant, however the interactive effect of substrate concentration and Ca(2+) concentration, ratio of inoculum to substrate and Ca(2+) concentration were found to be insignificant at 5% level. A maximum yield of 565.76 ml CH(4)/g VS(added) was estimated under the optimum conditions for substrate concentration 7.77 g of VS/l, inoculum to substrate ratio of 2.81 and calcium concentration of 380.82 mg/l. Verification experiment of the estimated optimum conditions confirmed that the RSM was useful for optimizing the methane yield from effluent of bio-hydrogen fermentation of food waste.     

Effects of inoculum size and age on biomass growth and paclitaxel production of elicitor-treated Taxus yunnanensis cell cultures

Suspension cultures of Taxus yunnanensis cells were inoculated with cells of different culture ages (12-24 days) at various densities [50-250 g fresh weight (fw)/l], and treated (on day 7) with a mixture of elicitors, including Ag(+), chitosan and methyl jasmonate. The biomass productivity (during the production stage) increased dramatically with inoculum size, but decreased with inoculum age over 16 days. The volumetric yield and productivity of taxol (paclitaxel) also increased with inoculum size, while the specific taxol yield (per cell) was mainly dependent on inoculum age, with an optimum of 20 days, during the early stationary phase. The highest taxol yield and productivity, 39.8 mg/l and 1.9 mg/l per day, respectively, were obtained with a 20-day-old inoculum at 200 g fw/l. Taxol excretion by the cells increased with inoculum age but decreased with inoculum size. The elicitor-induced activities of catalase (CAT) and phenylalanine ammonia-lyase (PAL) also depended mainly on inoculum age; higher PAL activity and lower CAT activity were obtained with an older inoculum, corresponding to a higher taxol yield. The results show that both inoculum size and age are important variables for taxol production, though the latter more profoundly influences elicitor-induced taxol biosynthesis of the cells. Inoculum size and age are also interrelated and should be optimized together in a two-stage culture process.     

一株脂肪酶产生菌的筛选及产酶条件优化研究

通过利用溴甲酚紫显色培养基初筛和酶活测定法复筛得到产脂肪酶的一株细菌HP2,经形态学观察和生理生化测定初步鉴定该菌株为不动杆菌属。并对该菌株的摇床培养产酶条件进行了初步研究,采用正交试验对HP2菌株发酵产脂肪酶的条件进行了优化,得到最佳发酵条件为初始pH为7.7,培养温度为35℃,接种量(V/V)为1.5%,发酵周期为48 h,酶活力达到129.7 U/mL。     

Xylanase production in solid state fermentation by Aspergillus niger mutant using statistical experimental designs

The initial moisture content, cultivation time, inoculum size and concentration of basal medium were optimized in solid state fermentation (SSF) for the production of xylanase by an Aspergillus niger mutant using statistical experimental designs. The cultivation time and concentration of basal medium were the most important factors affecting xylanase activity. An inoculum size of 5 x 10(5) spores/g, initial moisture content of 65%, cultivation time of 5 days and 10 times concentration of basal medium containing 50 times concentration of corn steep liquor were optimum for xylanase production in SSF. Under the optimized conditions, the activity and productivity of xylanase obtained after 5 days of fermentation were 5,071 IU/g of rice straw and 14,790 IU l(-1) h(-1), respectively. The xylanase activity predicted by a polynomial model was 5,484 IU/g of rice straw.     

高产纤维素酶枯草芽胞杆菌S-16的筛选及其发酵工艺优化

利用刚果红鉴别培养基及基础液体筛选培养基进行菌种筛选,从新疆盐碱地分离得到的16株菌株中筛选获得一株产纤维素酶活力较高的菌株S-16,对该菌株进行16SrDNA鉴定,确定该菌为枯草芽胞杆菌(Bacillus subtilis)。对S-16发酵产纤维素酶的主要影响因素进行研究,分别考察了碳源、氮源、培养基初始pH和接种量等因素对发酵产纤维素酶的影响。结合单因素影响实验得到优化后的培养基配方为:羧甲基纤维素钠1.5%,酵母粉1%,NaCl 1%,MgSO_4·7H_2O 2‰,KH_2PO_4·3H_2_O 1‰。优化后的发酵条件为:初始pH为8,接种量1%,种龄8h,培养时间48h。经过发酵工艺优化,S-16产生的羧甲基纤维素酶活(CMCase)和滤纸酶活(FPase)分别达到4.64IU/mL和0.46IU/mL,与初始培养条件下的酶活相比分别提高了3.14倍和1.30倍。本研究得到的枯草芽胞杆菌S-16及其优化发酵工艺为秸秆的快速腐熟和高产纤维素酶的应用奠定了基础。     

Synbiotics growth optimization of Bifidobacterium pseudocatenulatum G4 with prebiotics using a statistical methodology

Aims:  This study demonstrated the optimum growth of Bifidobacterium pseudocatenulatum G4 with prebiotics via statistical model.
Methods and Results:  Commercial prebiotics [inulin and fructooligosaccharide (FOS)], together with sorbitol, arabinan and inoculum rate, were tested by fractional factorial design to determine their impact on growth of Bif. pseudocatenulatum G4 in skim milk. At 48 h incubation, bacterial growth was mainly influenced by FOS and inoculum rate. Growth reduction was observed in all samples incubated for 72 h. Central composite design (CCD) was adopted using FOS and inoculum rate at 48 h incubation to develop the statistical model for optimization. The model predicted that 2·461 log CFU ml⁻¹ produced the optimum growth increase of Bif. pseudocatenulatum G4. The combination that produced the optimum point was 2·86% FOS (g/v) and 0·67% inoculum rate (v/v).
Conclusion:  At optimum combination of inoculum rate and FOS, validation experiments recorded 2·40 ± 10·02 log CFU ml⁻¹. The application in 1-l bioreactor for 24 h showed higher growth increase of 2·95 log CFU ml⁻¹.
Significant and Impact of the Study:  Response surface methodology approach is useful to develop optimum synbiotics combination for strain G4 with FOS.