叔丁醇体系中复合酶催化餐饮废油制备生物柴油工艺优化

以叔丁醇为反应体系,研究固定化Novozym 435 和Lipozyme TLIM 脂肪酶协同催化餐饮废油合成生物柴油.采用5 因素5 水平响应面法优化工艺参数,最佳工艺条件为:复合酶用量4%( wt.)、复合酶配比1:1(w/w),油/醇摩尔比1:5,反应温度50℃,叔丁醇用量50%(油体积比v/v).在此条件下反应10 h,生物柴油转化率为83.65 %.复合酶操作稳定性较高,重复使用10 个批次,生物柴油转化率仍保持在80% 以上.     

超声辅助酶促合成丙二酸单对硝基苄酯

为了研究超声对固定化脂肪酶Novozym 435催化合成丙二酸单对硝基苄酯反应的影响。对超声辅助酶促酯化反应条件进行了优化,确定最佳反应条件:以甲苯为溶剂,固定化脂肪酶Novozym 435质量浓度为3.0 g/L,对硝基苄醇质量浓度为4.0 g/L,反应温度为30℃,反应时间为5 h,超声声强为0.8 W/cm2,超声频率为20 k Hz,丙二酸单对硝基苄酯收率为89.7%。与振荡水浴条件相比,超声辅助酶催化反应能强化传质,在反应温度降低15℃,时间缩短3 h和固定化酶浓度减少1.5 g/L的同时,产物收率增加了18.2%。超声作用下,Novozym 435重复使用性能较佳,应用于酯化反应8次后,丙二酸单对硝基苄酯收率为69.3%。     

固定化脂肪酶催化毛棉籽油制备生物柴油

研究了固定化脂肪酶Lipozyme TL IM和Novozym435催化毛棉籽油和乙酸甲酯制备生物柴油的过程。通过向反应体系中添加甲醇,可减少乙酸的抑制,明显提高生物柴油得率,确定最佳反应条件为:正己烷作溶剂,乙酸甲酯与油摩尔比9:1,添加油重3%的甲醇、油重10%的LipozymeTLIM和5%的Novozym435复合使用,温度55°C,反应8h,生物柴油得率达到91.83%。最后探索了酶催化毛棉籽油合成生物柴油的动力学,得到动力学方程。     

固定化脂肪酶催化制备生物柴油条件优化

本文探讨了以固定化脂肪酶为催化剂催化制备生物柴油中醇油比、水含量、游离脂肪酸酸值和催化剂使用寿命对菜子油酯交换反应的影响,并与以NaOH、固体碱纳米水滑石为催化剂生物柴油的制备条件相比较.研究表明:固定化脂肪酶为催化剂所需最佳醇油比最低,仅为4:1,游离脂肪酸含量对酯交换反应影响甚微,且有较强的抗水性,固定化脂肪酶催化剂可可重复使用6次;NaOH为催化剂酯交换反应抗水性最强,随游离脂肪酸的增加,酯交换转化率显著降低;纳米水滑石为催化剂可重复使用5次,酯交换产物易分离,所得产品完全符合德国生物柴油标准.     

脂肪酶协同催化猪油合成生物柴油工艺研究

探讨了以乙酸甲酯为酰基受体两种脂肪酶协同催化猪油转酯合成生物柴油的工艺条件。首先利用单因子试验确定2种固定化脂肪酶Novozym435、Lipozyme TLIM单独作为催化剂时的最佳酶用量为40％,反应温度为50℃,乙酸甲酯用量为14（相对于油的摩尔比）。在此基础上,采用3因素5水平和3个中心点的中心组分旋转设计法研究了上述2种脂肪酶协同使用时脂肪酶用量（g/g）、混合酶的配比（%/%）以及乙酸甲酯用量诸因素共同作用对转酯反应转化率的影响。优化后的反应条件为：总酶用量为40％,混合酶配比为50/50,乙酸甲酯用量为14,在该条件下甲酯得率可达97.6％,比同质量的Novozym435、Lipozyme TLIM的催化活性分别高出7.6％、22.3％。表明脂肪酶协同催化猪油合成生物柴油工艺可以较好地提高甲酯得率,并且节约生产成本。     

微水相超声波协同固定化脂肪酶催化酯交换过程优化

超声波协同固定化脂肪酶催化制备生物柴油的最佳工艺条件为：超声波功率70W、叔丁醇为反应介质、叔丁醇用量3％（v／v）、醇油比3：1且甲醇分三批加入、反应温度40℃、水含量为2％（v／v）。副产物甘油对固定化脂肪酶使用寿命影响最大,使用后的固定化脂肪酶用丙酮洗去表面的甘油,进行酯交换反应,酶的稳定性大为提高,可连续使用16批次。     

固定化脂肪酶催化花椒籽皮油转酯化反应研究

采用固定化脂肪酶催化花椒籽皮油制备生物柴油,研究了该转酯化反应的工艺条件.结果表明:在脂肪酶用量25%(质量分数).含水量10%(质量分数),正己烷用量15%(质量分数).醇油比3:1.分三次添加甲醇,于反应温度45℃下反应时间24 h,固定化脂肪酶使花椒籽皮油的棕榈酸甲酯的转化率达到82.5%.     

荧光假单胞菌脂肪酶固定化及催化制备生物柴油的工艺研究

研究了不同因素对制备固定化荧光假单胞菌脂肪酶的影响及固定化酶的酶学性质,并初步探讨了利用该固定化酶制备生物柴油的工艺。以海藻酸钠明胶为复合载体,采用包埋法制备固定化荧光假单胞菌脂肪酶,考察了载酶量、颗粒直径等因子对固定化效果的影响,并用制备的固定化酶进行了酶促酯交换合成生物柴油的工艺研究,考察了反应条件如酶量、反应温度、甲醇流加方式、醇油比等因素对甲酯得率的影响。试验结果表明,制备固定化荧光假单胞菌脂肪酶的最优条件为:每克载体给酶量为300 IU,选用6号注射器针头(内径为0.5 mm);通过酯交换,催化大豆油合成生物柴油的最佳反应工艺参数为:固定化酶25%,醇油比4:1,含水量6%,反应温度40℃;此条件下反应35 h后,甲酯的最高得率可达82%。     

静置的固定化荧光假单胞菌脂肪酶(PFL)生物反应器中催化合成乙酸香茅酯

为提高脂肪酶催化合成乙酸香茅酯的效率,优化催化条件,通过物理吸附,将脂肪酶Pseudomonas fluorescens lipase(PFL)固定在脱脂棉上,与柱形瓶或滴定管形成简易的生物反应器,并用于催化香茅醇与乙酸乙烯酯反应,合成乙酸香茅酯。结果发现,即使在静置条件下,在脱脂棉固定化PFL瓶型生物反应器中,在37℃催化反应24 h,香茅醇转化成乙酸香茅酯的转化率达96%以上。同样在静置条件下,在脱脂棉固定化PFL管式生物反应器中,在室温下催化反应4 h,香茅醇转化成乙酸香茅酯的转化率达68.5%。显然,制备的固定化酶反应器具有高效的催化作用。     

间歇及连续式固定化酶反应生产生物柴油

探讨了利用本实验室自制的Candida sp99．125脂肪酶转酯化合成生物柴油的过程。在利用间歇式反应得到最佳反应条件的情况下利用固定床反应器生产生物柴油,经过初步优化的试验结果表明,在采用分级流加甲醇下,生物柴油的转化率可以达到93％左右,并且固定化酶的使用寿命超过480h。     

Enzymatic coproduction of biodiesel and glycerol carbonate from soybean oil and dimethyl carbonate

The enzymatic coproduction of biodiesel and glycerol carbonate by the transesterification of soybean oil was studied using lipase as catalyst in organic solvent. To produce biodiesel and glycerol carbonate simultaneously, experiments were designed sequentially. Enzyme screening, the molar ratio of dimethyl carbonate (DMC) to soybean oil, reaction temperature and solvent effects were investigated. The results of enzyme screening, at 100 g/L Novozym 435 (immobilized Candida antarctica lipase B), biodiesel and glycerol carbonate showed conversions of 58.7% and 50.7%, respectively. The optimal conditions were 60 °C, 100 g/L Novozym 435, 6.0:1 molar ratio with tert-butanol as solvent: 84.9% biodiesel and 92.0% glycerol carbonate production was achieved.     

Ultrasonic irradiation with vibration for biodiesel production from soybean oil by Novozym 435

The production of biodiesel with soybean oil and methanol through transesterification by Novozym 435 (Candida antarctica lipase B immobilized on polyacrylic resin) were conducted under two different conditions—ultrasonic irradiation and vibration to compare their overall effects. Compared with vibration, ultrasonic irradiation significantly enhanced the activity of Novozym 435. The reaction rate was further increased under the condition of ultrasonic irradiation with vibration (UIV). Effects of reaction conditions, such as ultrasonic power, water content, organic solvents, ratio of solvent/oil, ratio of methanol/oil, enzyme dosage and temperature on the activity of Novozym 435 were investigated under UIV. Under the optimum conditions (50% of ultrasonic power, 50 rpm vibration, water content of 0.5%, tert-amyl alcohol/oil volume ratio of 1:1, methanol/oil molar ratio of 6:1, 6% Novozym 435 and 40 °C), 96% yield of fatty acid methyl ester (FAME) could be achieved in 4 h. Furthermore, repeated use of Novozym 435 after five cycles showed no obvious loss in enzyme activity, which suggested this enzyme was stable under the UIV condition. These results indicated that UIV was a fast and efficient method for biodiesel production.     

Enzyme catalyzed transesterification of waste cooking oil with dimethyl carbonate

The detrimental effects of waste cooking oil on sewer system attracted attention toward its proper management and reusing this waste oil for making biodiesel provides commercial and environmental advantage. In the present study, biodiesel has been successfully produced from waste cooking oil and dimethyl carbonate by transesterification, instead of the conventional alcohol. In this optimization study, the effect of various reaction conditions such as solvent, time and temperature, molar ratio of DMC to oil, enzyme loading and reusability, on the yield of fatty acid methyl ester (FAME) has been studied. The Maximum conversion of FAMEs achieved was 77.87% under optimum conditions (solvent free system, reaction time of 24 h, 60 °C, molar ratio of DMC to oil 6:1, catalyst amount 10% Novozym 435 (based on the oil weight)). Moreover, there was no obvious loss in the conversion after lipases were reused for 6 batches under optimized conditions.     

Production of bioethanol and biodiesel using instant noodle waste

Instant noodle manufacturing waste was used as feedstock to convert it into two products, bioethanol and biodiesel. The raw material was pretreated to separate it into two potential feedstocks, starch residues and palm oil, for conversion to bioethanol and biodiesel, respectively. For the production of bioethanol, starch residues were converted into glucose by α-amylase and glucoamylase. To investigate the saccharification process of the pretreated starch residues, the optimal pretreatment conditions were determined. The bioethanol conversion reached 98.5 % of the theoretical maximum by Saccharomyces cerevisiae K35 fermentation after saccharification under optimized pretreatment conditions. Moreover, palm oil, isolated from the instant noodle waste, was converted into valuable biodiesel by use of immobilized lipase (Novozym 435). The effects of four categories of alcohol, oil-to-methanol ratio, reaction time, lipase concentration and water content on the conversion process were investigated. The maximum biodiesel conversion was 95.4 %.     

Lipase-catalyzed transesterification of rapeseed oils for biodiesel production with a novel organic solvent as the reaction medium

tert-Butanol, as a novel reaction medium, has been adopted for lipase-catalyzed transesterification of rapeseed oil for biodiesel production, with which both the negative effects caused by excessive methanol and by-product glycerol could be eliminated. Combined use of Lipozyme TL IM and Novozym 435 was proposed further to catalyze the methanolysis and the highest biodiesel yield of 95% could be achieved under the optimum conditions (tert-butanol/oil volume ratio 1:1; methanol/oil molar ratio 4:1; 3% Lipozyme TL IM and 1% Novozym 435 based on the oil weight; temperature 35 °C; 130 rpm, 12 h). There was no obvious loss in lipase activity even after being repeatedly used for 200 cycles with tert-butanol as the reaction medium. Furthermore, waste oil was also explored for biodiesel production and it has been found that lipase also showed good stability in this novel system.     

Enzymatic synthesis of fatty acid ethyl esters by utilizing camellia oil soapstocks and diethyl carbonate

This study was reported on a novel process for fatty acid ethyl esters preparation by transesterification and esterification from renewable low-cost feedstock camellia oil soapstocks and friendly acyl acceptor diethyl carbonate. The main components of product were 83.9% ethyl oleate, 8.9% ethyl palmitate, 4.7% ethyl linoleate and 2.1% ethyl stearate, which could be used as eco-friendly renewable resources or additives of industrial solvent and fossil fuel. The effects of molar ratio of diethyl carbonate to soapstocks oil, lipases, organic solvent, reaction temperature and time were investigated, and process conditions were optimized. The yield was up to 98.4% in solvent-free system with molar ratio of diethyl carbonate to soapstocks oil 3:1 and 5% Novozym 435 (based on the weight of soapstocks oil) at 50 °C and 180 rpm for 24 h. Moreover, there was no obvious loss in the yield after lipases were reused for 10 batches without treatment under optimized conditions.     

复合脂肪酶催化生物柴油的初步研究

初步探讨了复合脂肪酶催化生物柴油的工艺。优化了复合酶配比条件和叔丁醇反应体系。在无溶剂体系中,Novozym435分别与Lipozyme TLIM和Lipozyme RMIM均以70／30质量比混合时,甲酯得率分别达到94．52％和96．25％,比Novozym435单独催化时的甲酯得率分别提高了9．52％和9．99％。在叔丁醇体系中,当Novozym435与Li-pozyme TLIM和Lipozyme RMIM分别以60／40和80／20的质量比混合时,其甲酯得率分别为85．06％和81．5％,比Novozym435单独催化的效率分别提高了9．89％和7．48％。优化叔丁醇体系中复合酶催化条件后,甲酯得率达92％。     

Single-cell protein production from ram horn hydrolysate by bacteria

The alcoholysis (transesterification) of the refined cotton seed oil of Turkish origin with primary and secondary alcohols was investigated in the presence of an immobilized enzyme from Candida antarctica, commercially called Novozym 435 in a solvent-free medium. The optimum conditions of the methanolysis were as follows: 30% enzyme based on oil weight; oil/alcohol molar ratio 1:4; temperature: 50 degrees C and reaction time: 7 h. Maximum methyl esters (ME) yield was 91.5%. At the same conditions cotton seed oil was converted with short-chain primary and secondary alcohols to its corresponding esters with conversions between 72% and 94%. Our results indicated that alcoholysis products of cotton seed oil could be used as valuable intermediates in oleochemistry.