响应面法优化皱褶假丝酵母脂肪酶催化合成甾醇共轭亚油酸酯

以皱褶假丝酵母(Candida rugosa)脂肪酶为催化剂,在正己烷体系中催化植物甾醇与共轭亚油酸合成甾醇共轭亚油酸酯.以植物甾醇酯化率为考察指标,通过单因素实验和响应面实验确定最佳工艺参数为:酸醇摩尔比6∶1,反应温度40℃,酶用量9.6％(占底物质量),反应时间87 h.在此条件下,酯化率达97.5％.     

响应面法优化豆粕发酵产共轭亚油酸条件

为寻求以豆粕为主要基质产共轭亚油酸最佳发酵条件,采用响应面法优化其发酵条件.在单因素试验基础上,选择不同接种量、油脂添加量、发酵时间为自变量,共轭亚油酸产量为响应值,利用Box-Benhnken中心组合方法进行3因素3水平的试验设计,并做响应面分析,建立回归模型.结果表明,回归方程拟合性好,发酵最优条件为:接种量3.2％,油脂添加量1.93 g·(50 g豆粕)-1,初始pH6.0,在37℃发酵80 h.在此条件下,发酵豆粕中共轭亚油酸产量可达700.32 μg/g.这为生物发酵法生产共轭亚油酸提供研究基础.     

酶法合成共轭亚油酸型磷脂的研究

在非水相体系中利用固定化脂肪酶为催化剂,将共轭亚油酸酰基转移到磷脂分子中,合成富含共轭亚油酸(CLA)的改性磷脂。选用的三种常用的固定化脂肪酶中Lipozyme RM IM催化效率最高,最佳反应条件为:CLA乙酯与大豆粉末磷脂的摩尔比为4∶1,反应温度45℃。对反应产物中的CLA含量进行检测分析表明,48h后其含量可以达到31.3%。进行分离处理后,检测该产品的理化指标。     

酶法合成共轭亚油酸型磷脂的研究

在非水相体系中利用固定化脂肪酶为催化剂,将共轭亚油酸酰基转移到磷脂分子中,合成富含共轭亚油酸(CLA)的改性磷脂。选用的三种常用的固定化脂肪酶中Lipozyme RM IM催化效率最高,最佳反应条件为:CLA乙酯与大豆粉末磷脂的摩尔比为4∶1,反应温度45℃。对反应产物中的CLA含量进行检测分析表明,48h后其含量可以达到31.3%。进行分离处理后,检测该产品的理化指标。      

溶剂体系酶催化酸解反应合成富含共轭亚油酸油脂的研究

研究了溶剂体系中脂肪酶催化共轭亚油酸(CLA)与油脂酸解反应制备富含共轭亚油酸油脂的影响因素考察了温度、底物配比、酶量、体系水分、无机盐等因素对酯交换反应的影响结果表明,适宜的工艺条件是:水含量0.5％, 底物配比2:1,温度50℃,酶量200U/g油脂,在上述条件下反应12h,花生油中共轭亚油酸含量可达18％左右研究了溶剂体系中脂肪酶对共轭亚油酸异构体的底物选择性,结果表明,脂肪酶催化10,12-十八碳二烯酸酸解反应优于9,11-十八碳二烯酸酸     

响应面优化红花籽油碱异构化法制备共轭亚油酸的研究

以新疆优质红花籽油为原料,通过碱异构化法制备共轭亚油酸(CLA)。采用单因素试验研究了异构化过程中反应温度、反应时间、PEG-400用量、Fe(OH)_3用量对CLA转化率的影响,同时采用响应面法对制备工艺进行优化。结果表明:在红花籽油质量为20 g前提下,红花籽油碱异构化法制备共轭亚油酸的最佳工艺条件为以PEG-400为溶剂、Fe(OH)_3为催化剂、反应温度178℃、反应时间2.7 h、PEG-400用量265 m L、Fe(OH)_3用量6 g,在此条件下,CLA转化率为96.54%。     

响应面法优化重组亚油酸异构酶产酶条件

共轭亚油酸(CLA)广泛存在于多种食物中,具有减肥、抗癌、抗动脉粥状硬化和抗糖尿病等诸多生理活性。为了获得活性CLA高产,本文将突变的亚油酸异构酶克隆到大肠杆菌中表达,单因素试验确定最优产酶条件为发酵时间18 h、IPTG诱导浓度0.2mmol/L、20%装液、培养基初始p H7、诱导前菌体生物量OD_(600)=0.4、LA浓度0.5mg/m L、离子浓度0.02%;在此基础上采用响应曲面法优化重组大肠杆菌培养条件提高生产亚油酸异构酶的能力,根据响应面法实验结果分析显示,发酵时间、诱导前生物量和LA浓度对重组亚油酸异构酶的表达有显著影响且均为正效应。三个影响因素最佳组合为发酵时间19.5h、诱导前生物量OD600=0.47和LA浓度0.57 mg/mL,此时预测亚油酸异构酶催化LA转化为CLA最大量为143.33μg/m L。验证显示,发酵CLA的产量为141.75±0.14μg/m L,与预测产量相符;通过优化设计,提高了107.5%。     

响应面优化脂肪酶催化合成三棕榈酸甘油酯

以单因素实验为基础,采用响应面法优化脂肪酶CalB immo Plus在无溶剂体系中催化棕榈酸和甘油酯化反应合成三棕榈酯甘油酯工艺。结果表明：最佳合成工艺条件为反应时间12.8 h、底物摩尔比2.9∶?1、反应温度75?℃、加酶量4.4%,在此条件下,酯化率和甘三酯含量分别为95.44%和85.75%。     

响应面优化法尿素包合法分离共轭亚油酸2种异构体

目的优化尿素包合法,对共轭亚油酸2种主要异构体c9, t11-CLA和t10, c12-CLA进行分离(2种异构体比例近1:1)。方法在单因素实验基础上,以温度、尿素与油比例、乙醇与油比例3个因素为自变量,以t10, c12-CLA/c9, t11-CLA为响应值,利用响应面法优化了共轭亚油酸异构体的分离。结果优化后的实验条件为:在乙醇作溶剂的情况下,将共轭亚油酸、尿素和乙醇按1:2.5:5(V:V:V)配比,置于75℃水浴锅中水浴溶解,室温下搅拌冷却结晶。所得样品中t10,c12-CLA与c9,t11-CLA的比值高达2.47,且共轭亚油酸总量为97.3%。结论优化后的尿素包合法可有效分离CLA的2种异构体,提高t10, c12-CLA比例。     

响应面法优化黄秋葵籽油中亚油酸的共轭转化率

为了提高黄秋葵籽油中亚油酸的共轭转化率,在单因素实验的基础上,根据中心组合（Box-Benhnken）设计实验,以共轭亚油酸（CLA）的得率为响应值进行响应面分析,并建立了相应的回归模型。黄秋葵籽油中亚油酸共轭转化的最佳工艺条件为:反应时间4 h,反应温度162℃,籽油/KOH为1.9（m L/g）,丙二醇/籽油为2.0（m L/m L）,CLA转化率为74.20%,其中反应温度对转化率影响最大,反应时间与反应温度的交互作用显著。经验证,实测值（74.20%）与模型预测值（76.99%）基本一致,说明响应面法优化黄秋葵籽油中亚油酸的共轭转化工艺可行。      

Production of reduced calorie structured lipid by acidolysis of tripalmitin with capric acid: optimisation by response surface methodology

BACKGROUND: Structured lipids (SLs) containing medium‐chain fatty acids (C8:0–C12:0) in the 1‐ and 3‐positions and long‐chain fatty acids in the 2‐position of triacylglycerols have interesting applications as reduced calorie fats. The aim of this study was to produce an SL by inserting capric acid (CA, C8:0) into tripalmitin (TP) and to optimise the reaction conditions by response surface methodology (RSM) with a three‐level, three‐factor face‐centred cubic design. RESULTS: Lipozyme TL IM from Thermomyces lanuginosa was used for the acidolysis of TP with CA in n‐hexane. The effects of three independent parameters, namely substrate molar ratio, enzyme amount and reaction time, on CA incorporation into TP were optimised. The range of each parameter was selected as follows: substrate molar ratio (CA/TP), 4–8; enzyme amount, 9–15 wt% of total substrate; reaction time, 6–10 h. Optimal conditions were determined to be a CA/TP molar ratio of 6.5, an enzyme amount of 11.6 wt% and a reaction time of 8.9 h. Experiments conducted under these optimised conditions yielded an SL containing 35.7 wt% (44.9 mol%) CA. A second‐order polynomial model was obtained for CA incorporation. CONCLUSION: The possibility of enriching CA in TP by enzymatic acidolysis has been established. The SL containing 44.9 mol% CA produced under optimal conditions may be considered a reduced calorie fat. Copyright © 2008 Society of Chemical Industry     

Production of structured lipids containing conjugated linolenic acid: optimisation by response surface methodology

Structured lipids containing conjugated linolenic acid (CLNA) were produced separately by enzymatic acidolysis reaction of corn and canola oils (CAO) with bitter gourd (Momordica charantia L) seed oil fatty acids [bitter gourd seed oil fatty acids (BGFA)]. Reactions were conducted using a commercial immobilised sn‐1,3‐specific lipase from Thermomyces lanuginosa (Lipozyme TL IM) in hexane. The effects of reaction time, substrate molar ratio, temperature and enzyme amount on incorporation yield of CLNA were investigated and optimised by response surface methodology with three‐level, two‐factor face‐centred cube design. When reactions were conducted using 10% enzyme for 3 h, the optimum reaction conditions were found for corn oil (CO) as 53.5 °C and 5.9:1 BGFA/CO molar ratio. At these conditions, the incorporation of CLNA into CO was determined as 41.4%. However, CLNA incorporation into CAO was resulted as 37% at optimum conditions which were 54.2 °C and 6.8:1 BGFA/CAO molar ratio.     

Enzymatic transesterification of fractionated rice bran oil with conjugated linoleic acid: Optimization by response surface methodology

Rice bran oil (RBO) was fractionated at a low temperature (−16 °C) and the yield of fractionated solid (S-RBO) and liquid (L-RBO) phase were 66.5 and 33.5 g/100 g, respectively. The L-RBO contained more unsaturated fatty acids (81.8%) than S-RBO (76.1%). Response surface methodology (RSM) was used to determine the effects of three variables (water activity of lipase, reaction temperature and time) on the lipase catalyzed incorporation of conjugated linoleic acid (CLA) into L-RBO. We used CLA as the acyl due to its purported health benefits. The transesterified lipid (TL) contained palmitic (13.5%), oleic (37.5%), linoleic (26.6%) and CLA isomers (20.7%), respectively. According to ridge analysis, optimal reaction conditions for water activity of lipase, reaction temperature and time were 0.177, 55.66 °C and 29.25 h, respectively, for producing TL with maximum incorporation of CLA. The coefficient of determination (R²=0.94) showed that the fitted model explained 94% of the observation. The TL was reproduced to confirm the experimental incorporation with the estimated value. The data showed that the experimental response was reasonably close to the estimated response. These results suggested that RSM can be used to optimize lipase-catalyzed incorporation of CLA into the fractionated L-RBO.     

植物乳杆菌转化合成共轭亚油酸的培养基条件优化

生物法转化合成共轭亚油酸,产物中异构体组成单一,具有很好的应用前景。通过一株植物乳杆菌(Lactobacillus plantarum)合成共轭亚油酸的培养基成分进行优化,确定最优的培养基组成:葡萄糖20g/L,酵母浸出物40g/L,硫酸镁0.5g/L,硫酸锰0.5g/L,乙酸钠2g/L,磷酸氢二钾1g/L。优化后,共轭亚油酸产量达到0.259g/L,相比优化前(0.0455g/L)有了较大的提升。      

一株植物乳杆菌转化生成共轭亚油酸的特性研究

报道了一株植物乳杆菌(L.plantarumLT2-6)发酵转化亚油酸(LA)生成共轭亚油酸(CLA)的特性研究。微氧环境有利于CLA的生成;温度为37℃、初始pH为7.0、底物LA浓度为0.075%时,菌体生长及CLA生成量较高。时间曲线结果表明,接种后8h,CLA开始生成;发酵24h时,CLA生成量达到最高(0.29g/L),LA转化率为387%。生成的CLA产物主要为cis9,trans11/trans9,cis11-CLA。     

响应面法优化脂肪酶催化脂肪酸甲酯环氧化

以Novozyme 435脂肪酶为催化剂,在单因素实验的基础上,利用响应面法优化了脂肪酸甲酯(FAMEs)环氧化工艺.选择反应时间、脂肪酶用量和H2O2与FAMEs双键的摩尔比为自变量,环氧值为响应值,建立了脂肪酶催化FAMEs环氧化体系的二次回归模型.优化后的工艺条件为:在不加脂肪酸氧载体的条件下,FAMEs 20 g,甲苯用量30 mL,脂肪酶用量3％(以FAMEs质量计),H2O2与FAMEs双键摩尔比1.7∶1,反应温度40℃,反应时间5h.在此条件下,环氧值为4.82％,与模型预测值基本一致.     

Enzymatic production of low‐calorie structured lipid from Echium seed oil and lauric acid: optimisation by response surface methodology

Low‐calorie structured lipids (SLs) were produced from Echium seed oil and lauric acid by enzymatic acidolysis reactions. Lipozyme^® RM IM, commercially immobilised sn‐1,3 specific lipase derived from Rhizomucor miehei, was used in the reactions. The effects of substrate molar ratio and reaction time on incorporation of lauric acid were investigated and optimised by response surface technology (RSM) with five‐level, two‐factor central composite design. Good quadratic model was obtained for the response [lauric acid (%) incorporation]. Highest lauric acid incorporation into Echium oil was obtained at 5:1 lauric acid/Echium oil molar ratio and at 4‐h reaction time. The model was verified at these conditions and furthermore scale‐up synthesis of SLs was performed. At these conditions, SL contained predominantly lauric acid (42.8%), oleic acid (9.9%), linoleic acid (10.8%), α‐linolenic acid (15.1%), γ‐linolenic acid (7.5%) and stearidonic acid (8.5%) with% 64.4 of PUFA at sn‐2 position in gram‐scale synthesis.     

酶法合成高含量共轭亚油酸甘油酯

选用AB-8大孔弱极性树脂对脂肪酶进行固定化,固定化脂肪酶的活力为210U／g。用此固定化酶催化共轭亚油酸乙酯和大豆油合成富含共轭亚油酸（CLA）的改性大豆油,最佳反应条件为：底物摩尔比（n（CLA乙酯）：n（大豆油））1：0．33,酶加量21U／g,反应温度60℃。放大反应体系,对反应产物中的CLA含量进行检测分析表明,其含量可达37％。