鲍姆纤孔菌（桑黄）不同方式发酵的菌丝体生物活性比较

利用液体发酵、木屑固体发酵和米饭固体发酵3种方式培养鲍姆纤孔菌（桑黄）菌丝体,对菌丝体醇提物的体外抗氧化、抗肿瘤和抗衰老生物活性进行了研究。结果表明,木屑固体发酵、液体发酵和米饭固体发酵的菌丝体醇提物清除H2O2自由基的IC50值分别为78.28±0.32、27.73±0.57和7.84±0.37;米饭培养的桑黄菌丝体醇提物在低浓度500μg/mL下对超氧阴离子自由基清除作用到达80%,在相同的浓度下对DPPH自由基清除率也明显高于其他两种方法,表现出较高的抗氧化活性。木屑以及米饭培养方法得到的菌丝体对PC12神经细胞损伤修复均有较好的效果,液体培养的桑黄菌丝体表现的修复作用较低;液体发酵培养的菌丝体醇提物浓度在100μg/mL时,对肿瘤细胞HepG2的抑制率达70%,高于其他两种培养方法的抑制作用。     

响应面法优化干花豆总黄酮提取工艺研究

干花豆( Fordia cauliflora)的主要有效成分为黄酮类、生物碱、有机酸等,具有益智、抗衰老、抗炎等作用。目前的研究主要集中在化学成分及药理活性等方面,对总黄酮成分提取工艺优化报道较少。该研究以新鲜干花豆为材料,以总黄酮提取量为评价指标,在提取温度、料液比、乙醇浓度和提取时间单因素实验基础上,采用响应面法优化了干花豆总黄酮提取工艺,同时测定了总黄酮对1,1-二苯基苦基苯肼自由基( DPPH.)和羟基自由基(.OH)清除能力。结果表明：干花豆总黄酮提取最佳工艺条件为提取温度78℃、料液比为1∶30(g.mL-1)、乙醇浓度71％和提取时间为187 min。在此条件下,总黄酮得率预测值为10.61 mg.g-1,实际为10.53 mg.g-1,理论值与预测值的相对误差为0.76％;干花豆总黄酮对DPPH和OH自由基清除能力IC50值分别为14.09和78.43μg.mL-1,弱于Vc(8.11和67.95μg.mL-1)。该提取工艺稳定合理,准确可靠,是提取干花豆总黄酮的可行方法。该研究结果为干花豆中总黄酮成分的进一步开发利用奠定了基础。     

超声波辅助浸提毛木耳总黄酮类化合物的工艺优化

黄酮类化合物是一类重要的次生代谢产物,广泛存在于各种植物和真菌中,具有抗菌、抗癌、抗氧化等生物活性。本研究以提取毛木耳子实体中总黄酮量为考察指标,运用响应面分析法研究了超声功率、浸提时间、乙醇浓度和料液比4个因素对总黄酮提取量的影响,以获得提取毛木耳总黄酮的最优工艺。经响应面分析,各因素按照对响应值的影响顺序为：浸提时间＞超声功率＞乙醇浓度＞料液比,且超声功率、浸提时间、乙醇浓度对总黄酮提取量的影响极显著。结果表明提取毛木耳子实体中总黄酮含量的最优工艺为：超声功率168W、浸提时间50min、乙醇浓度60%、料液比1:7,总黄酮的最大预测提取量为2.11%。验证试验结果表明,总黄酮含量平均为2.08%,与理论值基本吻合。本研究将为食用菌中总黄酮的提取工艺提供理论基础。     

桦褐孔菌子实体多糖的提取及体外降血糖活性

通过响应面设计得到桦褐孔菌子实体Inonotus obliquus多糖的优化提取条件,利用酶和细胞体外实验,探究桦褐孔菌子实体多糖的降血糖活性,确定活性多糖组分,并初步分析其降糖机理及单糖组成.优化条件下多糖得率为(2.79±0.03)％.粗多糖经乙醇分级沉淀分别获得IOP30、IOP60、IOP80组分.其中IOP3...     

Optimization of dynamic-microwave assisted enzymatic hydrolysis extraction of total ginsenosides from stems and leaves of panax ginseng by response surface methodology

Abstract

Ginseng stems and leaves (GSAL) are abundant in ginsenosides compounds. For efficient utilization of GSAL and the enhancement of total ginsenosides (TG) compound yields in GSAL, TG from GSAL were extracted, using dynamic-microwave assisted extraction coupled with enzymatic hydrolysis (DMAE-EH) method. The extraction process has been simulated and its main influencing factors such as ethanol concentration, microwave temperature, microwave time and pump flow rate have been optimized by response surface methodology coupled with a Box-Behnken design(BBD). The experimental results indicated that optimal extraction conditions of TG from GSAL were as follows: ethanol concentration of 75%, microwave temperature of 60°C, microwave time of 20?min and pump flow rate of 38 r/min. After experimental verification, the experimental yields of TG was 60.62?±?0.85?mg?g^?1, which were well agreement with the predicted by the model. In general, the present results demonstrated that DMAE-EH method was successfully used to extract total ginsenosides in GSAL.     

Ultrasound-assisted aqueous extraction of total flavonoids and hydroxytyrosol from olive leaves optimized by response surface methodology

Abstract

Olive leaves were often extracted with methanol or ethanol at different proportions. In this study, ultrasound-assisted aqueous extraction was adopted for olive leaf extraction. The yields of total flavonoids (TF) and hydroxytyrosol (HT) were optimized by central composite experimental design. Two second-order polynomial equations were established to quantify the relationship between the responses and the processing parameters. Under the optimal condition of extracting at 60?°C for 60?min with the solvent-to-material ratio of 40, TF and HT amounted to 57.31?±?0.35 and 1.80?±?0.02?mg/g dry leaves (DL), respectively. The scavenging rate of all extracts against α, α-diphenyl-β-picrylhydrazyl (DPPH) and hydroxyl free radicals was screened. The integrated scores, representing both active ingredients and antioxidant capacity of the extracts, were calculated by principle component analysis (PCA). The optimal extract gained the highest score in PCA. In addition, compared to the extracts from 80% methanol to 44% ethanol, the ultrasound-assisted aqueous extract was richer in TF, HT, and polyphenols, while it also presented stronger ferric reducing antioxidant power (FRAP), but poorer strength to quench hydroxyl radicals. The study indicated that the aqueous extract of olive leaves may present broad potential opportunities in health-care sector.     

黑曲霉固态发酵生产单宁酶的条件优化

研究采用响应面法优化黑曲霉固态发酵生产单宁酶的培养条件。应用Plackett—Burman试验筛选出重要影响因子：五倍子粉含量、（NH4）2SO4浓度以及接种孢子量,最陡爬坡试验逼近最大响应区域。应用Box．Behnken响应面试验对重要影响因子进一步优化。得到最佳培养条件：每250mL三角瓶中装入1．0g五倍子粉、4．4g稻壳和0．5g麸皮、液固比（mL／g）2：1且营养盐溶液组成为（NH4）2s0421g/L、MgSO4·7H2O1g／L、NaCl1g／L,培养基pH自然,接种5．7×10^7个孢子后在30℃温度下培养4d。在此条件下,单宁酶产量从40U／g提高到114U／g,3次重复验证性试验平均值为115U／g,验证了模型的可靠性。     

酵母菌利用糖蜜发酵产麦角甾醇的工艺条件优化

麦角甾醇是由酵母菌产生的具有重要经济价值的代谢产物。为了提高酵母菌利用糖蜜发酵生产麦角甾醇的产量,通过响应面分析法优化了发酵培养基配方,并在5 L发酵罐对发酵过程pH控制和底物流加补料方式进行了优化。结果表明,利用优化后的发酵培养基,即糖蜜总糖40 g/L,KH2PO4 1 g/L,K2HPO4 1.86 g/L,CuSO4·5H2O 17.5 mg/L,FeSO4·7H2O 13.9 mg/L,MgSO4·5H2O 12.3 mg/L,玉米浆10 mL/L,麦角甾醇产量比优化前提高了29.5%;利用恒定pH控制策略,在5 L发酵罐进行分批发酵,使麦角甾醇产量提高了62.1%;进一步采用底物流加补料策略,使麦角甾醇产量达到1 953.85 mg/L,是分批发酵的3.2倍,而且麦角甾醇产率比分批发酵提高了42.7%。为酵母菌发酵糖蜜产麦角甾醇的产业化应用奠定了基础。     

刺梨茶总黄酮的提取工艺的建立及其抗氧化活性

为进一步开发并利用贵州独特野生资源刺梨茶,研究其总黄酮的提取工艺及体外抗氧化活性,本文采用单因素实验和响应曲面分析法优化刺梨茶中总黄酮的提取工艺,并经1,1-二苯基-2-三硝基苯肼(DPPH)法初步评价其抗氧化活性。结果表明,刺梨茶总黄酮最佳提取工艺为料液比(g∶mL)1∶26,乙醇浓度74%,提取温度75℃,提取时间120min。此条件下,刺梨茶总黄酮得率为2.190%,与预测值2.216%接近。刺梨茶总黄酮对DPPH具有较好的清除能力,其EC50值为0.012 27mg/mL,其清除DPPH的能力微弱于Vc,但强于2,6-二叔丁基对甲酚(BHT)。刺梨茶总黄酮表现出良好的抗氧化活性,可作为天然抗氧化剂开发利用。     

Ethanol production from xylose by Fusarium oxysporum and the optimization of culture conditions

Bioethanol is the most commonly used renewable biofuel as an alternative to fossil fuels. Many microbial strains can convert lignocellulosics into bioethanol. However, very few natural strains with a high capability of fermenting pentose sugars and simultaneously utilizing various sugars have been reported. In this study, fermentation of sugar by Fusarium oxysporum G was performed for the production of ethanol to improve the performance of the fermentation process. The influences of pH, substrate concentration, temperature, and rotation speed on ethanol fermentation are investigated. The three significant factors (pH, substrate concentration, and temperature) are further optimized by quadratic orthogonal rotation regression combination design and response surface methodology (RSM). The optimum conditions are pH 4, 40?g/L of xylose, 32?°C, and 110?rpm obtained through single factor experiment design. Finally, it is found that the maximum ethanol production (10.0?g/L) can be achieved after 7 d of fermentation under conditions of pH 3.87, 45.2?g/L of xylose, and 30.4?°C. Glucose is utilized preferentially for the glucose–xylose mixture during the initial fermentation stage, but glucose and xylose are synchronously consumed without preference in the second period. These findings are significant for the potential industrial application of this strain for bioethanol production.     

双水相萃取法分离竹叶黄酮的工艺研究

以竹叶黄酮水提溶液为原料,采用PEG(聚乙二醇)/(NH4)2SO4双水相体系对竹叶黄酮进行萃取,考察了PEG平均相对分子质量、PEG质量分数、(NH4)2SO4质量分数、pH值、NaCl质量分数、原液质量分数、萃取温度等对双水相及竹叶黄酮萃取效果的影响。双水相萃取法提取竹叶黄酮的最优条件为:PEG 400 31%,(NH4)2SO411%,pH 3.9,NaCl 0.7%,原液51.5%,萃取温度20℃,在此条件下得到的竹叶黄酮萃取率为97.8%。结果说明,双水相萃取法操作简单方便,成本低,不会引起生物质失活或变性,适合于黄酮类化合物的萃取分离。     

Biosynthesis regulation of natamycin production from Streptomyces natalensis HDMNTE-01 enhanced by response surface methodology

Natamycin has been widely applied in medical treatments and food protection widely due to its effective inhibition to the growth of yeast and mold. As polyene macrolide antibiotic, the biosynthesis pathway of natamycin is relatively clear. To regulate the biosynthesis of natamycin, additions of precursors affecting cell growth and natamycin production were investigated. The results showed that 0.003% (w/v) potassium ferrocyanide and sodium propionate: n-butanol at a ratio of 4:1 was added into the broth at 0 and 24?hr, respectively, and they contributed to yield natamycin, reaching 1.62?g?L^?1 (174.6% higher than control). Furthermore, response surface methodology was undertaken to enhance natamycin production by Streptomyces natalensis HDMNTE-01 (a wild strain). The optimum conditions determined were: glucose 3.97%; soya peptone 2%; yeast extract 0.5%; original pH 7.0; inoculum volume 6%; growth in a 250-mL flask containing 24.68?mL of medium; shaken (220?rpm) at 28°C for 4 days. Under the optimized conditions, the yield was 2.81?g?L^?1 natamycin in 5-L fermentor when the fermentation was processed.     

响应面设计法优化仙鹤草总多酚的超声提取工艺

在单因素实验的基础上,采用响应面分析法对影响超声辅助提取仙鹤草总多酚得率的主要因素(超声温度、料液比和乙醇浓度)进行优化,建立了影响因素与总多酚之间的函数关系。获得最佳工艺条件为:71%乙醇,料液比1∶24,超声提取温度60℃,提取时间20 min。在此最佳条件下,总多酚得率为3.56%,试验结果与模型预测值相符。     

Phytase from Citrobacter koseri PM-7: Enhanced production using statistical method and application in ameliorating mineral bioaccessibility and protein digestibility of high-phytate food

The present study was aimed at enhancing phytase (Phy-Ck) production from Citrobacter koseri PM-7 using response surface methodology (RSM) and improving the bioaccessibility of minerals (Fe and Zn) and protein digestibility in high-phytate food using Phy-Ck. A five-variable and three-level central composite design of RSM using wheat bran (6.681%, w/v), inoculum level (2.5%, v/v), and triton X-100 (0.2%, v/v) resulted in up to 5.57-fold (1.047 U/ml) improvement in Phy-Ck yield from C. koseri PM-7 when compared with fermentation media I and II. The model was successfully validated in the design space by taking a random set of variable combinations. Treatment of high-phytate food with partially purified Phy-Ck showed improvement in mineral bioaccessibility maximally for defatted sesame flour (DSF) (Fe 45.5%; Zn 50.7%) followed by wheat flour (WF) (Fe 13.5%; Zn 14.4%), green gram flour (GGF) (Fe 0.7%; Zn 3.8%) and defatted groundnut flour (DGF) (Zn 5.6%). The in vitro protein digestibility (IVPD) of WF increased from 48.83 to 65.04%, GGF from 45.04 to 57.12%, and DSF from 47.34 to 55.7% after Phy-Ck treatment.     

粘性嗜热链球菌ST-1产胞外多糖发酵条件优化

应用响应面法对一株粘性嗜热链球菌ST-1的产胞外多糖的发酵条件进行了优化.根据单因素的实验结果,选取接种量,发酵温度,发酵时间作为考察因素,以胞外多糖的产量作为响应值,利用Box-Behnken实验设计方法,建立了胞外多糖产量与三个考察因素之间的回归方程并得到最佳发酵条件为:接种量5%,发酵时间14 h,发酵温度42℃...     

响应面法优化荷叶离褶伞菌丝体产漆酶条件

为了对荷叶离褶伞产漆酶条件进行优化,在单因素实验基础上,通过最陡爬坡实验(PB)对培养基8因素进行筛选,获得影响产漆酶的3个显著性因素:葡萄糖,pH和KH₂PO₄;通过中心组合(CCD)设计及响应面分析确定了最优发酵条件:葡萄糖20.09g/L,酪蛋白1.5g/L,酵母提取物1.5g/L,MgSO₄ 3g/L,CuSO₄ 3.75mg/L,KH₂PO₄ 3.97g/L,pH 4.98,VB₁ 0.1g/L,愈创木酚12mg/L,该条件下,漆酶酶活为829.83U/mL,较未优化对照提高46.6%.     

基于响应面设计脂肪酶Novo435催化合成甘油二酯的工艺优化

以甘油、油酸为原料,优化在无溶剂体系中以固定化脂肪酶Novo435催化合成甘油二酯（diglyceride,DAG）的工艺。系统考察底物摩尔比（油酸／甘油）、反应温度、时间和加酶量等因素对油酸转化率和甘油二酯含量影响的基础上,利用响应面试验设计优化各主效因子,并经回归分析获得最优的工艺条件。所得最优条件：油酸与甘油底物摩尔比2．27、反应温度48．14℃、反应时间6．3h、加酶量1．68％。在此条件下,实验测得油酸转化率为45．42％,甘油二酯质量分数为70．01％,与响应面模型预测值吻合。     

响应面优化纤维素酶辅助提取木豆叶总黄酮工艺

为探讨纤维素酶辅助提取木豆叶总黄酮最佳工艺条件,在单因素试验基础上,以酶用量、酶解温度、酶解时间和酶解pH为影响因子,总黄酮得率为响应值,采用Box-behnken中心组合设计建立4个影响因子与总黄酮得率关系的数学模型,进行响应面法分析。结果表明,纤维素酶辅助提取木豆叶总黄酮的最佳工艺条件为：酶用量为8.65 mg,酶解温度为33.88℃,酶解时间为2.02 h,酶解pH为5.02。在最优条件下总黄酮理论得率为4.86%,实测值为4.88%,拟合得到的模型与实际吻合良好。本研究建立的提取工艺条件稳定可靠,为以后木豆叶总黄酮的应用开发提供实验依据。     

响应面法优化产酰胺酶发酵培养基

采用响应面分析方法,对阿萨希丝孢酵母（Trichosporon asahii）ZZB-1产酰胺酶的发酵培养基进行了优化。运用单N子试验筛选出麦芽糖和酵母浸膏为最适碳源、氮源,金属离子Ca^2＋、Mn^2＋可提高发酵酰胺酶产量;通过最陡爬坡实验逼近以上4个因子的最大响应区域后,采用Box—Behnken响应面分析法,确定产酰胺酶最佳发酵培养基为麦芽糖18．84g／L、酵母浸膏9．55g／L、NaC15g／L、KH2PO41g／L、MgSO4·7H2O0．2g／L、FeS040．001g／L、CaC0370．84μmol／L、MnS0465．39肚mo[／L（1％丙烯酸诱导）,NH4·H2O调节pH至7．0。培养基优化后酰胺酶产量由初始2554U／L提高到4156U／L,为原始发酵培养基配方酶活产量的1．63倍。     

响应面法对红法夫酵母合成虾青素主要影响因素的优化

在单因素试验确定了红法夫酵母生物合成虾青素培养基组份的基础上,用响应面法对其浓度进行优化。首先用分式析因设计评价了培养基的各组份对虾青素产量的影响,并找出主要影响因子为蔗糖和酵母粉,二者分别达到了极显著和显著水平。用最陡爬坡路径逼近最大响应区域后,运用旋转中心复合设计及响应面分析,确定了主要影响因子的最佳浓度。其中,蔗糖的最佳浓度为49.8g/L,酵母粉的浓度为9.6g/L。菌株在优化培养基中的虾青素产量为9861μg/L,比优化前增加了近1倍。