超声波对酶法制备MLM型结构脂质的影响

比较不同超声条件对无溶剂体系中固定化脂肪酶Lipozyme TL IM催化酯交换合成MLM结构脂质的影响.研究表明,超声时间4 min,超声功率100 W,超声工作/间歇方式5 s/10 s,间歇分次超声2次,辛酸结合率在反应产物甘三酯中达到最高.固定化脂肪酶Lipozyme TL IM在以上反应体系中重复使用10次,其酯交换酶活力降低50%.短时间超声条件对无溶剂体系中固定化脂肪酶Lipozyme TL IM催化酯交换合成MLM结构脂质有促进作用.     

生物酶催化废白土油制备生物柴油的工艺研究

研究生物酶催化废白土油与甲醇酯交换制备生物柴油的最佳工艺条件。通过对比相当用量的Lipozyme TL IM和Novozyme 435的催化效果,筛选出Lipozyme TL IM为适宜的酶;在此基础上,以醇油摩尔比、生物酶添加量、反应温度、反应时间为自变量,生物柴油得率为响应值,进行酯交换制备生物柴油的响应面优化实验。结果表明,酯交换反应最佳条件为：醇油摩尔比4∶1,Lipozyme TL IM添加量10%(以废白土油质量计),反应温度35℃,反应时间15 h;在此条件下,生物柴油得率为95.9%,所得生物柴油非常接近0#柴油的质量标准。     

超临界酶法酯交换合成结构脂质中酶活力的研究

超临界酯交换合成结构脂质的反应中使用脂肪酶Lipozyme RM IM,不同的工艺条件对脂肪酶的催化活性会有影响.当反应温度为45℃,底物摩尔比(辛酸乙酯:鱼油)为15:1,酶用量为底物总量的10%,添加水量为酶量的30%,反应时间为11h,超临界CO2压力为12.5 MPa时,脂肪酶Lipozyme RM IM的催化效果最好,辛酸结合率在反应产物甘三酯中达最大值.肪脂酶Lipozyme RMIM在以上反应体系中重复使用17次,其酯交换活力降低50%.     

超声辅助脂肪酶催化合成富含n-3多不饱和脂肪酸磷脂的研究

以脂肪酶Lipozyme TL IM为催化剂,研究了合成富含n-3多不饱和脂肪酸磷脂的最佳工艺条件,即以正庚烷:异辛烷:正已烷=8:1:1为超声介质,溶剂(mL)/底物(g)=2,酶用量为25%,超声介质中水分质量分数为2%,超声功率70 W,55℃下连续超声5.5 h,在此条件下酯交换到磷脂上的DHA和EPA总质量分数为22.99%。由此可见,通过超声辅助及酯交换条件的优化,不仅可以大大缩短反应所需的时间,而且也能充分激活Lipozyme TL IM的酶活力,从而提高酯化反应的效率。     

酶催化桑蚕蛹油酯交换制备中长链脂肪酸甘油酯

以桑蚕蛹油为底物,通过酶法催化其与三辛酸甘油酯进行酯交换反应,制备富含α-亚麻酸的中长链脂肪酸甘油三酯(MLCTs)。通过单因素实验考察了酶种类、底物质量比、反应温度、加酶量以及反应时间对酯交换反应的影响,对酯交换条件进行了优化。结果表明,最佳反应条件为：采用Lipozyme TL IM脂肪酶,三辛酸甘油三酯与桑蚕蛹油质量比1∶ 4,加酶量为底物质量的8%,反应温度45 ℃,反应时间10 h。在最佳反应条件下,酯交换反应的转化率为98.42%,酯交换产物中中长链脂肪酸甘油三酯含量为98.73%,辛酸含量为20.00%,α-亚麻酸含量为30.09%。     

高温气相色谱法分析油脂随机酯交换反应程度研究

以大豆油和极度氢化棕榈油为原料进行酯交换反应,利用高温气相色谱法分析反应前后各种三酰甘油组成的变化,研究了不同催化剂催化酯交换反应的酯交换率,从而评判催化剂催化效果。采用此方法,利用单因素试验对Lipozyme 435脂肪酶催化大豆油与极度氢化棕榈油酯交换的参数进行了研究,得到适合的反应条件为:反应温度90℃、反应时间4 h、加酶量4%(占油脂总质量)、大豆油与氢化棕榈油质量比4∶3。在此条件下反应随机酯交换率为98.3%。     

猪油与棕榈硬脂酶法酯交换制备零反式脂肪酸起酥油的研究

研究了固定化脂肪酶Lipozyme RM IM催化猪油和棕榈硬脂酯交换制备起酥油的工艺,考察了反应温度、酶添加量、反应时间对酯交换反应的影响.并以反应后体系在20℃下的固体脂肪含量(SFC)为指标,确定了理想的工艺条件:反应温度60℃,酶添加量8％,反应时间1h.利用等温曲线和X-射线衍射技术研究了混合体系酯交换前后的相容性和晶体形态,结果表明:经酯交换后,混合体系的相容性得到显著改善,晶型由β型转变为β’型,适宜用作焙烤起酥油.     

固定化酶在连续制备酯交换中的稳定性研究

考察Lipozyme TL IM脂肪酶在填充床无溶剂条件下,连续酯交换过程中的操作稳定性。混合油为棕榈油硬脂、椰子油和色拉油的比例为60∶30∶10,酶反应器的操作温度为70℃,反应时间为100 h,混合油在反应器的停留时间为13.94 min。与酯交换前的混合油脂相比,酯交换产物的氧化稳定性更高,SFC35℃降低了33%,提高了人造黄油的可操作性及口感。     

棕榈油硬脂和大豆油酶法酯交换的研究

进行了固定化脂肪酶Lipozyme TL IM催化棕榈油硬脂和大豆油酶法酯交换的研究,考察了酶法酯交换分批操作的反应动力学曲线,发现5%的加酶量、70℃下反应,反应3 h内达到平衡,反应温度在70~90℃对反应速度无明显影响。采用填充床式反应器进行连续反应,结果表明通过装有10 g脂肪酶柱子的最佳流速为30 g/h。对化学酯交换和酶法酯交换产品性质的比较发现,二者SFC无明显差异。采用填充床式反应器对40∶60和30∶70的棕榈油硬脂和大豆油的混合物进行酶法酯交换反应,测定了反应产物的SFC曲线,为将来的应用开发提供参考数据。     

影响酶催化制备类可可脂过程中酰基位移和酯交换因素研究

该文研究棕榈油中间熔点物(POMF)与硬脂酸(StA)进行酶酯交换制备类可可脂。利用胰脂酶定向水解和Lipozyme TL IM脂肪酶酯交换的特性,结合TLC和GC法分析Sn–2位酰基转移率和酯交换的程度。从而得出棕榈油中间物制备类可可脂的反应条件:POMF为5 g,水活度为0.43,加酶量为10%,底物质量比为1∶1.8,振荡速度为150 r/min,反应温度60℃,反应时间10 h。此时,酯交换程度为75.70%,酰基转移率为12.30%,产品的滑动熔点为31³5℃,酸值为1.2mgKOH/g。     

超临界体系酶催化制备甘油二酯及其纯化

以二氧化碳为流体,在超临界体系中用脂肪酶催化大豆油脂与甘油反应制备甘油二酯及其纯化研究。选取Lipozyme RMIM、Novozyme 435、Lipozyme TLIM 三种固定化脂肪酶为试验酶进行酯化反应,通过单因素试验,分别确定3种酶的最佳工艺条件,3种酶的最佳添加量分别为2.5%、3%、8%;反应温度分别为65、70、65℃,反应时间分别为7、8、9h,底物比均为2:1,得甘油二酯含量分别为68.6%、67.7%、64.8%。采用二级分子蒸馏工艺对超临界体系生产的甘油二酯混合物进行纯化,甘油二酯产品纯度从68.6%提高到90.4%,产品得率为60.0%。综合考虑,在工业生产中,建议用脂肪酶Lipozyme RMIM。     

Lipase-catalyzed acidolysis of lard for the production of human milk fat substitute

Human milk fat substitute (HMFS) was prepared by Lipozyme RM IM-catalyzed acidolysis of lard and fatty acids obtained from palm kernel oil, tea seed oil and soybean oil, in a solvent-free system. The effects of substrate mass ratio, Lipozyme RM IM load and reaction time on the total fatty acids composition and sn-2 fatty acids composition were investigated. To optimize the reaction conditions, an orthogonal design was selected with three levels and three factors. Substrate mass ratio, Lipozyme RM IM load and reaction time were the factors employed. Under the given reaction temperature of 60 °C, the optimal reaction conditions were, 1/2 mass ratio of lard/fatty acids blend, 7% Lipozyme RM IM load and 1-h reaction time. By the “deducting score” principle, the produced HMFS in comparison with the reported HMFS possessed highest degree of similarity with local HMF from Guangzhou mothers. The results showed that it was possible to produce HMFS through the scale-up enzymatic acidolysis.     

Enzymatic synthesis of structured lipids using a novel cold-active lipase from Pichia lynferdii NRRL Y-7723

Structured lipids (SL) were synthesized by the acidolysis of borage oil with caprylic acid using lipases. Six commercial lipases from different sources and a novel lipase from Pichia lynferdii NRRL Y-7723 were screened for their acidolysis activities and Lipozyme RM IM and NRRL Y-7723 lipase were selected to synthesize symmetrical SL since recently NRRL Y-7723 lipase was identified as a novel cold-active lipase. Both lipases showed 1,3-regiospecifity toward the glycerol backbone of borage oil. The effects of enzyme loading and temperature on caprylic acid incorporation into the borage oil were investigated. For Lipozyme RM IM and NRRL Y-7723 lipase, the incorporation of caprylic acid increased as enzyme loading increased up to 4% of total weight of the substrate, but significant increases were not observed when enzyme loading was further increased. The activity of NRRL Y-7723 lipase was higher than that of Lipozyme RM IM in the temperature range between 10 and 20 °C.     

酶法合成棕榈酸马铃薯淀粉酯

以马铃薯原淀粉和棕榈酸为原料,在无溶剂体系下,以LipozymeTLIM为催化剂合成棕榈酸淀粉酯。考察了脂肪酶添加量、底物配比、反应时间、反应温度对淀粉酯合成的影响。确定了最适反应条件为脂肪酶添加量为6%(干淀粉),淀粉棕榈酸质量比为3:10,反应时间60h,反应温度65℃,产物取代度可达0.0351。对产品进行淀粉-碘复合物吸收光谱和红外光谱检测,证明合成了棕榈酸淀粉酯。     

无溶剂体系合成1,3-甘油二酯用脂肪酶的筛选及其酯化性质

对不同来源的脂肪酶进行了系统的筛选,并根据位置专一性的差别将脂肪酶分为1,3 特异的、1,3 选择性和非选择性的3类.采用LipozymeRMIM在无溶剂系统中催化甘油、脂肪酸合成1,3 sn 甘油二酯.研究表明脂肪酸、底物醇种类、温度、水分活度对LipozymeRMIM的活力有明显的影响.     

Lipase-catalyzed synthesis and characterization of flaxseed oil-based structured lipids

The biosynthesis of structured lipids (SLs) was carried out by the interesterification of flaxseed oil (FO) and tricaprylin (TC) in an organic solvent medium (OSM), using selected commercial lipases, including Amano DF, Novozym 435, Lipozyme TL-IM and Lipozyme RM-IM. The fatty acyl chains of the synthesized triacylglycerols (TAGs) were identified by atmospheric pressure chemical ionization/mass spectrometric (APCI/MS) analysis, while the fatty acid positional distribution of the MLM- and MML-SLs (M-medium and L-long chain fatty acids) was determined by silver-ion high-performance liquid chromatographic (Ag⁺/HPLC) analysis. The effects of reaction temperature (T_r, 30–50 °C), enzyme concentration (E_c, 0.5–4%, w/v), initial water activity (a_w, 0.05–0.43) and reaction time (R_t, 0–72 h) on the efficiency of the enzymes, were studied. The bioconversion yield (%) of the synthesized MLM- and MML-SLs was monitored under the established reaction parameters for each lipase. The maximum yield of MLM-SLs was obtained in the order, of Novozym 435 > Lipozyme TL-IM > Lipozyme RM-IM > Amano DF. Moreover, considering the ratio of the MLM- to MML-SLs produced by each enzyme, Novozym 435 and Lipozyme TL-IM were selected as the most effective enzymes for interesterification of FO and TC.     

Production and structural analysis of triacylglycerols containing capric acid and conjugated linoleic acid isomers obtained by enzymatic acidolysis

BACKGROUND: Structured lipids containing medium‐chain fatty acids have interesting applications as reduced‐calorie fats; moreover, conjugated linoleic acid (CLA) isomers have shown interesting biological properties. The aim of this study was to synthesize triacylglycerols (TAGs) containing capric acid in the sn‐1‐ and sn‐3‐ positions and CLA isomers in the sn‐2‐ position, using different commercial available lipases. RESULTS: The homogeneous CLA‐TAGs (Tri‐CLA) were chemically synthesized starting from glycerol and CLA isomers, 9‐cis,11‐trans and 10‐trans,12‐cis CLA. The acidolysis reactions of Tri‐CLA with capric acid were carried out at 55 °C for different times in hexane; after 96 h the acidolysis average yield was 65%. The best capric acid incorporation in total TAGs was obtained after 96 h with Lipozyme IM (56.6%). The results of structural analysis carried out on the obtained TAGs showed that both Novozyme 435 and anhydrous Lipozyme IM gave the best incorporation of capric acid in sn‐1(3)‐ positions (61.8%). However, anhydrous Lipozyme IM gave also the highest CLA percent content in sn‐2‐ position (73.2%). CONCLUSION: Anhydrous Lipozyme IM appears to be the more effective enzyme in acidolysis reactions to obtain structured TAGs containing CLA isomers in the central position and capric acid at external positions. Copyright © 2009 Society of Chemical Industry     

Biosynthesis of oleyl oleate wax ester by non-commercial lipase

Oleyl oleate can be considered a synthetic analogue of jojoba oil. This one has been the main natural source of wax esters for commercial applications since the global ban on whale hunting. Lipase catalyzed production of this ester was carried out using oleic acid and oleyl alcohol in a solvent-free system. Lipase from Rhizopus sp. CBMAI 1127 was used as the biocatalyst and commercial enzyme Lipozyme TL IM? was used to compare results. The acid/alcohol molar ratio showed significant effects for both lipases and the amount of enzyme had a significant effect just for Lipozyme TL IM?. The rate of the esterification reaction using lipase from Rhizopus sp. CBMAI 1127 was very similar to that obtained with commercial lipase. The present study also evaluated antimicrobial and emulsifying properties of this ester. Emulsifying capacity of the synthesized oleyl oleate was lower than Tween 80 and sodium dodecyl sulfate, and no antimicrobial activity was observed.     

Production of olive oil enriched with medium chain fatty acids catalysed by commercial immobilised lipases

Structured triacylglycerols, containing medium chain fatty acids, were produced by acidolysis of virgin olive oil with caprylic or capric acid, at a molar ratio of olive oil:fatty acid of 1:2, at 45 °C for 24 h, in solvent-free media or in n-hexane, catalysed by Thermomyces lanuginosa (Lipozyme TL IM), Rhizomucor miehei (Lipozyme RM IM) and Candida antarctica (Novozym 435) immobilised lipases. Incorporations were always greater for capric than for caprylic acid. For both acids, higher incorporations were always attained in solvent-free media: the highest caprylic acid incorporations were obtained with Novozym 435 (25.5 mol%) and Lipozyme RM IM (25.7 mol%), while similar capric acid incorporations were obtained with all biocatalysts (27.1–30.4 mol%).     

Chemoenzymatic synthesis of structured triacylglycerols with conjugated linoleic acids (CLA) in central position

A chemoenzymatic process for the production of structured triacylglycerols (TAG) containing CLA at sn2 position and lauric acid at external ones is proposed. First, castor bean oil was chemically dehydrated and isomerised to obtain a new modified oil with very high proportion of CLA (>95%). Then, this new oil was used for enzymatic transesterification allowing the grafting of lauric acid at external positions of the TAG backbone by using 1,3 regioselective enzymes. Among these, Aspergillus niger lipase was not satisfactory giving very low lauroyl incorporation (<5%) On the contrary, lipases from Thermomyces lanuginosa (Lipozyme TL IM) and from Carica papaya latex allowed good reaction yields. The effect of the type of acyl donor was studied. With alkyl esters T. lanuginosa lipase provided a final incorporation of 58.9% after 72 h corresponding to 88.4% transesterification yield. Concerning C. papaya lipase, incorporation of lauroyl residues was lower than Lipozyme TL IM. This lipase exhibited higher performance with lauric acid accounting for 44.7% lauroyl incorporation at the end of reaction for a 67.1% transesterification yield. The effect of the substrates mole ratio was also evaluated. It was observed that a 1:3 TAG/acyl donor mole ratio was the most efficient for both lipases. Finally, fatty acids regiodistribution of the newly formed structured TAG was determined. With Lipozyme TL IM, the proportion of lauric acid incorporated at the sn2 position did not exceed 5.4% after 72 h while with C. papaya lipase a more pronounced incorporation of lauroyl residues at the central position (8.8%) was observed.