米糠蛋白抗氧化活性肽的制备

以水解度(DH％)和对DPPH自由基清除率为指标,筛选出制备米糠蛋白抗氧化活性肽的最适蛋白酶.研究最适蛋白酶的酶解条件,探讨底物浓度、蛋白酶的加入量、pH值、酶解时间等因素对水解度(DH％)和DPPH自由基清除率的影响;在单因素基础上采用Box-Behnken响应曲面中心组合设计法,对酶解米糠蛋白的工艺进行优化.试验结果表明,在加酶量13970.82 U/g,时间3.05h,底物浓度4.97％的水解条件下,米糠蛋白的水解度能够达到23.67％,活性肽对DPPH自由基清除率达到64.26％.     

响应面法优化黄绿蜜环菌子实体蛋白酶解条件

黄绿蜜环菌（Armillaria luteo—virens Sacc）子实体中蛋白含量很高,采用酶水解黄绿蜜环菌子实体蛋白的方法是生产具有生物学功能特性的活性肽的有效途径。实验采用酸性蛋白酶、中性蛋白酶和碱性蛋白酶水解黄绿蜜环菌子实体蛋白制备生物活性肽。实验中确定了酶解前处理条件,即最适宜的酶制剂为中性蛋白酶。酶解条件的优化采用中心组合响应面分析法：建立数学模型回归分析,模型评价,最后进行验证实验。结果表明：底物浓度为7．6％、加酶量为1．6％、酶解温度为52％、酶解时间为6．4h,此条件下蛋白水解度最高。     

双酶法制备螺旋藻多肽的工艺研究

选用碱性蛋白酶和木瓜蛋白酶结合的双酶法对螺旋藻蛋白进行水解。其中,对木瓜蛋白酶水解螺旋藻蛋白的工艺进行优化。以水解度为指标,研究了酶解时间、酶与底物比、pH和酶解温度4种因素对酶解反应的影响。在此基础上设计了3因素(加酶量、酶解温度和pH)3水平的响应面试验。结果表明碱性蛋白酶水解螺旋藻蛋白的最佳酶解条件为:加酶量4300 U/g,pH 7.0,酶解温度55℃,酶解时间160 min;木瓜蛋白酶的最佳酶解条件为:酶底比为4.5%,酶解温度60℃,pH 6.5,酶解时间210 min。利用碱性蛋白酶和木瓜蛋白酶结合的双酶法制得的多肽水解度可达32.90%,与单酶法相比,水解度明显提高。     

固定化酶解猪小肠黏膜制备肝素的工艺研究

本文以肝素效价为指标,探索了固定化胰蛋白酶对小肠黏膜的酶解作用。在单因素试验基础上采用Box-Behnken中心组合试验设计和响应面(RSM)分析法,以肝素效价为响应值,通过考察p H值、加酶量、酶解温度及料液比,优化了固定化胰蛋白酶酶解制备肝素的工艺,建立了二次回归方程。结果表明,p H值、酶解温度、加酶量、及料液比均对肝素提取具有显著影响。固定化酶制备肝素最佳工艺条件为:p H为11,加酶质量分数为0.24%,酶解温度为46℃,料液比为1∶3.3(g/m L),酶解时间为5 h,在此条件下获得肝素酶解液效价为15.28 U。     

响应面法优化人工蛹虫草子实体中虫草酸微波提取工艺

为优化人工蛹虫草子实体中虫草酸的微波提取工艺,在单因素试验基础上,利用响应曲面法考察提取时间、微波功率和液固比对虫草酸提取率的影响,优化提取工艺.结果表明:人工培养蛹虫草子实体中虫草酸微波提取的优化工艺条件为:微波功率555 W,液固比35 mL/g,提取时间4min,提取2次,虫草酸提取率的理论值可达84.45％.     

酶解法去除胭脂虫红色素提取液中蛋白工艺研究

本文对酶解胭脂虫体内蛋白工艺过程进行了研究,首先通过实验筛选出了木瓜蛋白酶为酶制剂,重点在单因素实验的基础上,选用了Box—Benhnken响应面分析法,得到了酶解工艺过程优化工艺条件：加酶量为3％、酶解时间为5h、温度为45℃、溶液pH值为5,水解率为4．72％。     

Study on Optimal Conditions of Degradation of Wheat Straw by Cellulase and Analysis of Kinetics

以小麦秸秆为原料,通过正交实验对纤维素酶降解秸秆纤维的影响因素进行了研究.结果表明,影响小麦秸秆降解的因素依次为:酶量＞酶解时间＞料液比＞反应温度,其最适条件是:加酶量为40 u/g,酶解时间为10h,反应温度为40℃,料液比为1∶3,总糖含量达到43.24％.以米氏方程为基础,建立起最适酶解条件下总纤维素降解的动力学模型.     

蛋白鲜味肽调味品生产工艺初探

蛋白二次酶解技术生产蛋白鲜味肽能够在保有传统鲜味的同时,有效提高蛋白质得率,利于人体吸收。试验根据不同水产品的呈味特点,选择沙丁鱼和对虾为实验原料,利用复合蛋白酶对原料进行初步定向酶解并超滤,制备具有独特风味的短肽。采用响应面法优化酶解水产蛋白工艺,水解度作响应值,以探究酶添加量、酶解温度、时间及pH值对鲜味肽得率的影响,得到初步酶解制备鲜味肽最优工艺条件：复合蛋白酶加酶量3.3%、温度57℃、酶解时间3.5h、pH为7.1。     

海参制备胶原蛋白肽工艺研究

主要研究以海参体壁为原料制备胶原蛋白肽的工艺条件,通过单因素和正交试验对酶解条件进行优化。结果表明,使用木瓜蛋白酶的酶解效果最好,最佳酶解条件为:酶解温度55℃、p H值7.0、加酶量2%、料液比1:30和提取时间3 h,此条件下海参胶原蛋白肽水解度达到14.23%。     

响应面法优化豆粕固态发酵工艺的研究

采用SAS 9.1.3中的响应面分析法（中心组合一致精度设计）对影响豆粕固态发酵中蛋白质水解的四个主要因素（料水比,加酶量,发酵时间,接种量）进行了优化,考察了各因素及其交互作用对大豆蛋白水解度的影响。通过模拟二次多项式回归预测模型并建立了影响因素与响应值（水解度）之间的函数关系,即回归方程,根据回归方程寻优得出,当料水比1：1.00,加酶量2.55％,发酵时间65h,接种量1.00％时水解度可达13.3％,且比优化前提高了56％。     

水酶法提取紫苏籽油脂工艺

采用中心组合设计(CCD)-响应面(RSM)优化紫苏籽油脂的水酶法提取工艺。在单因素试验的基础上采用中心组合设计方法,研究了酶的种类、酶解温度、pH、液(mL)固(g)比、加酶量、以及时间相互作用对紫苏油脂提取率的影响。结果显示,拟合得到方程显著,确定的紫苏油脂提取最优条件为:碱性蛋白酶在pH9.5条件下液(mL)固(g)比9.97∶1、加酶量2.75%、温度56.1℃、时间5.25h,该条件下紫苏油脂的提取率可达到37.65%,与理论值38.3%十分接近,建立的模型真实可靠,确定了紫苏油脂的最佳提取工艺。经气相色谱检测紫苏籽油中含有棕榈酸、硬脂酸、油酸、亚油酸、α-亚麻酸等脂肪酸,水酶法提取紫苏油脂的α-亚麻酸相对含量最高67.9%,且相对溶剂法及冷榨法理化指标最好。     

Pretreatment of lignocellulosic biomass using ultrasound aiming at obtaining fermentable sugar

This study aims to evaluate the activity of the cellulase enzyme forward the use of ultrasound technology in different conditions of temperature, pH and exposure time, as well, to match the steps of pretreatment and enzymatic hydrolysis in one step. A central composite design (CCRD) and response surface analysis were used to evaluate the effect of ultrasound power, temperature and pH on enzyme activity. Optimum condition in the studied range was 30% for ultrasound power, pH 4.6 and 50?°C, yielding an enzyme activity of 15.5 UPF/mL. From this, we carried out kinetics of enzymatic hydrolysis on filter paper and bagasse malt, in optimized conditions. Total reducing sugars (TRS) were 3.85 and 0.46?mg/mL when the filter paper and bagasse malt were used as substrate, respectively. Ultrasound showed to be a good technology to increase the enzyme activity aiming to intensify enzymatic processes.     

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。     

Statistical optimization of sulfite pretreatment of corncob residues for high concentration ethanol production

In this study, a central composite design of response surface method was used to optimize sulfite pretreatment of corncob residues, in respect to sulfite charge (5-10%), treatment time (1-2h), liquid/solid (l/s) ratio (6:1-10:1) and temperature (150-180°C) for maximizing glucose production in enzymatic hydrolysis process. The relative optimum condition was obtained as follows: sulfite charge 7.1%, l/s ratio 7.6:1, temperature 156°C for 1.4h, corresponding to 79.3% total glucan converted to glucose+cellobiose. In the subsequent simultaneous saccharification and fermentation (SSF) experiments using 15% glucan substrates pretreated under this kind of conditions, 60.8 g ethanol l(-1) with 72.2% theoretical yield was obtained.     

Optimization of Enzymatic Hydrolysis Conditions of Caspian kutum (Rutilus frisii kutum)ˮ By-product for Production of Bioactive Peptides with Antioxidative Properties

The enzymatic hydrolysis was performed by Alcalase to recover the fish protein hydrolysate from Caspian kutum by-product (CB). The degree of hydrolysis (DH) was applied for monitoring the hydrolysis reaction of CB. The response surface methodology was applied based on a D-optimal design to perform the optimization process for obtaining the high yield of CB protein hydrolysate. The effect of four independent variables including pH (7.5–8.5), temperature (45–55 °C), time (1–3 h), and enzyme concentration (0.5–1.5% w/w) on DH was studied. The results indicated that the predicted and actual values of the optimum condition had no significant difference. The optimum enzymatic hydrolysis conditions were achieved at pH 8.5, temperature of 55 °C, enzyme concentration of 1.5% w/w, and time of 3 h, which resulted in the maximum value of DH (19.08%). Antioxidant assays including DPPH scavenging and metal chelating activities showed that Caspian kutum protein hydrolysates had antioxidant properties.

     

Pretreatment of rapeseed straw by sodium hydroxide

Pretreatment method for rapeseed straw by sodium hydroxide was investigated for production of bioethanol and biobutanol. Various pretreatment parameters, including temperature, time, and sodium hydroxide concentration were optimized using a statistical method which is a central composite design of response surface methodology. In the case of sodium hydroxide pretreatment, optimal pretreatment conditions were found to be 7.9% sodium hydroxide concentration, 5.5 h of reaction time, and 68.4 °C of reaction temperature. The maximum glucose yield which can be recovered by enzymatic hydrolysis at the optimum conditions was 95.7% and the experimental result was 94.0 ± 4.8%. This experimental result was in agreement with the model prediction. An increase of surface area and pore size in pretreated rapeseed straw by sodium hydroxide pretreatment was observed by scanning electron microscope.     

Process Modeling of Enzymatic Hydrolysis of Wet-Exploded Corn Stover

The aim of this work was to investigate the optimal process conditions leading to high glucose yield (over 80 %) after wet explosion (WEx) pretreatment and enzymatic hydrolysis. The study focused on determining the “sweet spot” where the glucose yield obtained is optimized compared to the cost of the enzymes. WEx pretreatment was conducted at different temperatures, times, and oxygen concentrations to determine the best WEx pretreatment conditions for the most efficient enzymatic hydrolysis. Enzymatic hydrolysis was further optimized at the optimal conditions using central composite design of response surface methodology with respect to two variables: Cellic® CTec2 loading [5 to 40 mg enzyme protein (EP)/g glucan] and substrate concentration (SC) (5 to 20 %) at 50 °C for 72 h. The most efficient and economic conditions for corn stover conversion to glucose were obtained when wet-exploded at 170 °C for 20 min with 5.5 bar oxygen followed by enzymatic hydrolysis at 20 % SC and 15 mg EP/g glucan (5 filter paper units) resulting in a glucose yield of 84 %.     

Optimization of fermentation conditions for alcohol production

The quantitative effects of carbohydrate levels, degree of initial saccharification, glucoamylase dosage, temperature, and fermentation time were investigated using a Box-Wilson central composite design protocol. With Saccharomyces cerevisiae ATCC 4126, it was found that the use of a partially saccharified starch substrate markedly increased yields and attainable alcohol levels. Balancing the degree of initial saccharification with the level of glucoamylase used to complete hydrolysis was found necessary to obtain optimum yields. The temperature optimum was found to be 36 degrees C. The regression equations obtained were used to model the fermentation in order to determine optimum fermentation conditions.     

The effect of process conditions on the alpha-amylolytic hydrolysis of amylopectin potato starch: An experimental design approach

The hydrolysis of amylopectin potato starch with Bacillus licheniformis alpha-amylase (Maxamyl) was studied under industrially relevant conditions (i.e. high dry-weight concentrations). The following ranges of process conditions were chosen and investigated by means of an experimental design: pH [5.6-7.6]; calcium addition [0-120 microg/g]; temperature [63-97 degrees C]; dry-weight concentration [3-37% [w/w]]; enzyme dosage [27.6-372.4 microL/kg] and stirring [0-200 rpm]. The rate of hydrolysis was followed as a function of the theoretical dextrose equivalent. The highest rate (at a dextrose equivalent of 10) was observed at high temperature (90 degrees C) and low pH (6). At a higher pH (7.2), the maximum temperature of hydrolysis shifted to a lower value. Also, high levels of calcium resulted in a decrease of the maximum temperature of hydrolysis. The pH, temperature, and the amount of enzyme added showed interactive effects on the observed rate of hydrolysis. No product or substrate inhibition was observed. Stirring did not effect the rate of hydrolysis. The oligosaccharide composition after hydrolysis (at a certain dextrose equivalent) did depend on the reaction temperature. The level of maltopentaose [15-24% [w/w]], a major product of starch hydrolysis by B. licheniformis alpha-amylase, was influenced mostly by temperature.     

Maximization of bioconversion of castor oil into ricinoleic acid by response surface methodology

In this study, response surface methodology was applied to optimize process variables like temperature, pH, enzyme concentration (mg/g oil), and buffer concentration (g/g oil) for hydrolysis of castor oil using Candida rugosa lipase. A 2⁴ full factorial central composite design was used to develop the quadratic model that was subsequently optimized and the optimal conditions were as follows: temperature 40 °C, pH 7.72, enzyme concentration 5.28 mg/g oil, buffer concentration 1 g/g oil and there was 65.5% conversion in 6 h. These predicted optimal conditions agreed well with the experimental results. This is the first report on the application of response surface methodology in castor oil hydrolysis using C. rugosa lipase with higher percentage conversion in 6 h.