脂肪酶催化合成生物表面活性剂

脂肪酸单甘油酯、脂肪酸糖酯、聚甘油脂肪酸酯和长链脂肪酸蜡酯是重要的生物表面活性剂。传统化学法以碱为催化剂在高温下进行,不仅能耗高且产品纯度低。脂肪酶作为一种天然生物催化剂,可以温和条件下催化合成上述生物表面活性剂,能耗低且产品纯度高。综述对脂肪酶催化合成生物表面活笥剂工艺路线、反应体系及操作参数。     

固定化少根根霉发酵产脂肪酶及催化合成单甘酯

采用多种载体固定少根根霉细胞发酵产脂肪酶，发现珍珠岩和聚氨酯泡沫比较适合作固定化载体，发酵液酶活性比无载体直接发酵高6~8倍，而且产酶后固定化根霉细胞的废载体有较高酶活性，可直接作固定化细胞用于催化化学反应. 对根霉脂肪酶的性质进行了初步探讨. 提取的脂肪酶和固定化根霉细胞用于催化合成单甘酯，效果显著.     

不饱和脂肪酸甲酯环氧化工艺的研究进展

以催化剂体系为主线,综述了近年来化学法和脂肪酶法制备无毒增塑剂环氧脂肪酸甲酯的研究现状。对杂多酸和离子液体等化学催化体系和酶催化体系的优缺点进行了评述;集中讨论了脂肪酶催化法中氧载体、底物物质的量比、H2O2滴加速度、反应温度等因素对不饱和脂肪酸甲酯环氧化过程的影响规律;分析了脂肪酶的固载化技术以及存在的相关问题。指出寻找合适载体固载脂肪酶、提高脂肪酶的活性和稳定性、探寻适宜的环氧化工艺条件、提高脂肪酶的利用率是下一步的开发方向。     

非水相酶催化技术的应用

该项目利用非水相酶催化技术开发了光学活性环氧丙醇、手性2-辛醇、鲸蜡油、类可可酯和单酰甘油酯5个酶反应新产品,并提供了适合工业化应用的酶法生产新工艺。采用具有水解(S)-环氧丙醇丁酸酯专一性的根霉脂肪酶得到光学纯度超过95％e.e.的(R)-环氧丙醇丁酸酯;开发了固定化酶和双亲分子非共价修饰酶相协同的新方法,拆分得到的(S)-2-辛醇的光学纯度达98.0％e.e.;采用无溶剂系统,在63L反应器中进行了中试放大试验,所得鲸蜡油产品含蜡量达到95％;以资源丰富、价廉的乌桕脂为原料,利用1,3-位选择性脂肪酶和有机相中酶促反应,制得类可可脂纯度超过90％;以假单胞菌脂肪酶为催化剂进行无溶剂法棕榈油甘油解反应制得单甘酯,并在15L反应器中进行了放大试验,产品中单甘酯含量为76.0％,还对单甘酯在化妆品中的应用进行了初步研究。     

新型载体PEI修饰树脂固定化脂肪酶及其在对2-氯丙酸酯拆分中的应用

目的:研究新型载体PEI修饰树脂固定化脂肪酶及其在对2-氯丙酸酯拆分中的应用。方法:使用新型载体PEI修饰树脂固定化脂肪酶,并使用固化后的脂肪酶对2-氯丙酸酯进行拆分。结果:PEI在反应温度为34℃时对光学活性2-氯丙酸的生成量最佳,且固化后的脂肪酶拆分光学活性2-氯丙酸的效果最好。结论:对2-氯丙酸酯使用新型载体PEI修饰树脂固定化后的脂肪酶进行拆分能高效的获取光学活性的2-氯丙酸酯。     

固定化脂肪酶的载体材料

脂肪酶是一种羧基酯水解酶,能够逐步将甘油三酯水解成甘油和脂肪酸,也可以催化酯交换、酯合成等反应,广泛应用于食品、能源及医药等工业领域。但是,脂肪酶在应用环境中结构易被破坏而丧失活性。固定化脂肪酶是提高酶稳定性的一种有效手段,并能保持更高的催化活性。不同的固定化材料对酶的活性影响也不同,本文综述了固定化脂肪酶的无机、有机载体材料,以及近年来备受关注的纳米载体材料的研究进展,分析了各类材料的优缺点,并展望了固定化脂肪酶应用前景。     

丙酮中麦芽糖月桂酸单酯的酶法选择性合成

为选择性地合成麦芽糖月桂酸单酯,该文研究了脂肪酶催化合成条件对麦芽糖月桂酸酯浓度和产率的影响,确定了麦芽糖月桂酸单酯的最佳合成参数。当c(麦芽糖)=25 mmol/L、c(月桂酸)=75 mmol/L、ρ(脂肪酶)=20 g/L、ρ(3A分子筛)=60 g/L时,在丙酮中50℃反应72 h,麦芽糖月桂酸单酯的产率和浓度分别可达93%和23.35 mmol/L。     

响应面优化褶皱假丝酵母脂肪酶催化合成木质甾醇油酸酯

以木质甾醇转化率为指标,考察了10种常见商业化脂肪酶催化合成木质甾醇油酸酯的效果,确定褶皱假丝酵母脂肪酶(CRL)为优选生物催化剂,进一步筛选出正己烷为优选反应介质.在脂肪酶用量、油酸和木质甾醇的物质的量比、反应温度和反应时间这4个单因素考察基础上,通过响应面分析法对酶催化木质甾醇油酸酯合成工艺条件进行优化,并对优化条件进行验证和放大实验.CRL催化合成木质甾醇油酸酯的优化工艺参数为:CRL添加量为木质甾醇质量的10％,油酸与木质甾醇的物质的量比为3.8:1,反应温度为46℃,反应时间为28 h,木质甾醇的转化率为91.56％±0.25％.     

技术市场

脂肪酶合成维生素A棕榈酸酯维生素A、维生素A醋酸酯、维生素A棕榈酯是我国可允许添加的维生素A系列添加剂,但是维生素A、维生素A醋酸酯对热、光极不稳定。维生素A棕榈酯相对维生素A、维生素A醋酸酯具有化学性质稳定,不易分解等优点,已广泛应用于化妆品、药物、饲料等。该项目中的发酵法生产脂肪酶部分属于国家“九五”攻关课题,现已经完成了中试,积累了成熟的技术资料,通过了国家鉴证,并于1997年申请了国家专利:固定化脂肪酶催化合成脂肪酸低碳醇酯,专利授理号为02117514·0。该技术的特点:酶法合成工艺简便,具有反应条件温和、催化反应…     

酶法生产棕榈酸异辛酯首获成功

北京化工大学采用脂肪酶催化法合成棕榈酸异辛酯项目通过北京市科委的技术鉴定。专家认定该技术为国内外首创,达到国际领先水平。目前,国内外棕榈酸异辛酯的生产方法全都为化学法,生产能耗大,而且产品颜色较深,反应转化率一般在85 %～92 %。北京化工大学开发的酶法技术则采用棕榈酸和异辛醇在脂肪酶催化下合成棕榈酸异辛酯。这种方法与化学法相比,具有能耗低,环境污染小,不存在因酸碱催化剂产生污水问题,转化率达到95 %以上,生产成本低等优点。目前已建立了30 0t/a脂肪酶催化合成棕榈酸异辛酯的工业化装置。棕榈酸异辛酯热稳定性好,并具有内…     

Enzymatische Herstellung von festen Fettsäuremonoglyceriden

Enzymatic Preparation of Solid Fatty Acid Monoglycerides Lipases can be used to synthesize monoglycerides from solid fatty acids and glycerol. We have examined the conditions of such reaction systems with a view to developing a simple technical process. The selectivity of the Penicillium cyclopium and Rhizopus sp. lipases were studied at high rates of fatty acid turnover. By the correct choice of lipase, temperature and water content, the reaction may be steered in the direction of either monoglycerides of diglycerides. Using the Penicillium lipase under narrowly defined reaction conditions a highly selective monoglyceride synthesis is possible. Di glycerides are almost the sole products when using the Rhizopus lipase at 40°C. At 20°C, but under otherwise identical conditions, the main products are monoglycerides. The Penicillium lipase catalyzes the synthesis of monoglycerides at both 20°C and 40°C, provided that the water content of the glycerine is less than 10%. At a glycerol concentration of 80% the selectivity changes such that more diglycerides are formed. The enzymatic synthesis of glycerides can be so regulated that more than 95% of the available fatty acid is incorporated into monoglyceride. After melting the reaction mixture and allowing it to stand for less than an hour, the phases separate and excess glycerol can be separated very simply. A product conforming to industry specifications can then be produced by distilling off the trace amounts of remaining glycerol from the lipid phase.     

聚乙烯醇-壳聚糖复合酶膜的制备及在单甘油酯合成中的应用

引　言脂肪酶有机相酶催化在有机合成及手性药物合成中有重要用途[1],这些反应大都是在油水两相中进行 ,脂肪酶是一种界面酶 ,在两相界面上反应活性最高 .为增大比表面积 ,在反应体系中加入表面活性剂或采用反胶团体系进行脂肪酶催化反应[2 ],但加入表面活性剂后对后续产物的分离纯化带来不利影响 .采用酶膜反应器进行脂肪酶两相反应是近年来的一个发展方向 ,即将脂肪酶固定在膜上 ,油水两相分别走膜两侧 ,并在膜表面接触反应 ,反应生产的产物可及时被两相带走 ,从而避免了两相直接接触乳化的问题[3].目前脂肪酶是通过吸附或交联固定在疏水…     

CAY10499, a novel monoglyceride lipase inhibitor evidenced by an expeditious MGL assay

Monoglyceride lipase (MGL) plays a major role in the metabolism of the lipid transmitter 2-arachidonoylglycerol (2-AG). This endocannabinoid is known to mediate a large number of physiological processes, and its regulation is thought to be of great therapeutic potential. However, the number of available monoglyceride lipase inhibitors is limited, mostly due to the lack of rapid and accurate pharmacological assays for the enzyme. We have developed a 96-well-format assay for MGL using a nonradiolabeled substrate, 4-nitrophenylacetate. The IC(50) values that were obtained for known inhibitors of MGL using 4-nitrophenylacetate were similar to those reported by using the radiolabeled form of an endogenous substrate, 2-oleoylglycerol. In a first small-scale screening, we identified CAY10499 as a novel monoglyceride lipase inhibitor. Thus, we report here the characterization of this submicromolar inhibitor, which acts on MGL through an unprecedented mechanism for inhibitors of this enzyme.     

PREPARATION OF PVA/CHITOSAN LIPASE MEMBRANE AND ITS APPLICATION IN SYNTHESIS OF MONOGLYCERIDE

PVA/Chitosan(CS) composite membrane was used for enzyme processing of fats and oils. The concentration of lipase and cross-linking agent which influence the immobilization of lipase in membrane were determined. Epichlorohydrin is used as the cross-linking agent. The immobilized lipase is 0.66 u·cm -2 and the recovery of immobilized lipase is 24%. The membrane reactor was tested to synthesis monoglyceride(MG), which could be used many times without loss conversion yield of MG. The PVA/CS lipase membrane reactor is a new reactor for lipase catalytic biphase systems.     

Enzymatic glycerolysis of a triglyceride in aqueous and nonaqueous microemulsions

Enzymatic solvolysis of a model triglyceride, palm oil, was performed in microemulsions containing isooctane, sodiumbis(2-ethylhexyl)sulfosuccinate (AOT), palm oil and a combination of water and glycerol as the polar component. Using a 1,3-specific lipase both hydrolysis, leading to the formation of fatty acid and one mole of monoglyceride, and glycerolysis, giving three moles of monoglyceride, occur. The reaction was very slow in a completely nonaqueous system. Addition of a small amount of water led to an increased rate of glycerolysis, in addition to hydrolysis. It was found that by using³H labelled material reaction products originating from the two reactions were formed in equimolar amounts. The products probably emanate from a common intermediate. The molar ratio, R, of water and glycerol to surfactant turned out to be critical, optimum R-value being 3.4. Four different lipases, one from porcine pancreas and three of fungal origin, were tested. No marked differences in ratio of monoglyceride to fatty acid formed were obtained, indicating that the ratio between glycerolysis and hydrolysis is constant regardless of the lipase used.     

Triglyceride specificity ofCandida cylindracea lipase: Effect of docosahexaenoic acid on resistance of triglyceride to lipase

Tuna oil was hydrolyzed withCandida cylindracea lipase. After 70% hydrolysis of the oil, the docosahexaenoic acid (DHA) content in the glyceride mixture [a mixture of TG (triglyceride), DG (diglyceride) and MG (monoglyceride)] was twice that of the original oil. DHA-rich TG and DG were observed, but DHA-rich MG was absent.C. cylin-dracea lipase seemed to have a “triglyceride specificity,” and it favors TG without DHA over TG containing DHA. In accordance with this hypothesis, TG containing a mixture of oleic acid (OA) and DHA was synthesized and then hydrolyzed withC. cylindracea lipase. TGs in the hydrolysis product were fractionated and analyzed quantitatively by high-performance liquid chromatography. Four kinds of TGs were obtained. TG with three molecules of OA was hydrolyzed most easily. Increasing the DHA content of TG resulted in less hydrolysis of TG. The results suggested thatC. cylindracea lipase had a TG specificity for the whole structure of TG in preference to the individual ester bonds; OA coexisting with DHA in TG was resistant toC. cylindracea lipase due to the TG structure.     

单甘油硼酸酯镁阻燃剂的合成

以硼酸和甘油为起始原料,在75℃条件下反应2.5 h,合成中间体单甘油硼酸酯;再用中间体单甘油硼酸酯与氧化镁在110℃条件下反应3.5 h合成单甘油硼酸酯镁。产品收率达到87.77%。采用红外的表征方法对合成的产物进行分析,利用络合滴定的方法测定镁含量为17.5%。     

PREPARATION OF PVA/CHITOSAN LIPASE MEMBRANE REACTOR AND ITS APPLICATION TO SYNTHESIS OF MONOGLYCERIDE

PVA/ Chitosan (CS) composite membrane was studied in this paper, which could be used for enzyme processing of fat and oils. The parameters such as concentration of lipase, pH, and cross-linking agent as well as metal ions, which influence the immobilization of lipase in membrane, were optimized. The immobilized lipase was 0.66 u/cm2 and the recovery of immobilized lipase activity was 24%. The membrane reactor could be used to synthesize monoglyceride (MG) with many batches.