Lipase and photodecarboxylase coexpression: A potential strategy for alkane-based biodiesel production from natural triglycerides

Alkane-based biodiesel is considered the next generation of biodiesel owing to its potential environmental benefits and the fact that it exhibits much higher specific caloric values than traditional biodiesel.However,the formidable obstacle impeding the commercialization of this cutting-edge fuel alternative lies in the cost associated with its production.In this study,an engineered strain Escherichia coli(E.coli)showcasing harmonized coexpression of a lipase(from Thermomyces lanuginosus lipase,TLL)and a fatty acid photodecarboxylase(from Chlorella variabilis,CvFAP)was first constructed to transform triglycerides into alkanes.The potential of E.coli BL21(DE3)/pRSFDuet-1-TLL-CvFAP for alkane synthesis was evaluated with tripalmitin as a model substrate under various process conditions.Following a comprehensive examination of the reaction parameters,the scope of the biotransformation was expanded to‘real’substrates(vegetable oils).The results showed that bioderived oils can be transformed into alkanes with high yields(0.80-10.20 mmol·L^(-1))under mild conditions(35℃,pH 8.0,and 36 h)and blue light illumination.The selected processes were performed on an increased lab scale(up to 100 ml)with up to 24.77 mmol·L^(-1) tripalmitin,leading to a yield of 18.89 mmol·L^(-1) pentadecane.With the employment of a method for efficiently producing alkanes under mild conditions and a simple procedure to isolate alkanes from the reaction system,the utilization of sustainable biomass as a fundamental feedstock emerges as the primary solution to lower the cost of alkane-based biodiesel.Thus,this study proposes a readily implementable and highly effective approach for alkane-based biodiesel production.

Tetrathiafulvalene esters with high redox potentials and improved solubilities for non-aqueous redox flow battery applications

The exploitation of high performance redox-active substances is critically important for the development of non-aqueous redoxflow batteries.Herein,three tetrathiofulvalene(TTF)derivatives with different substitution groups,namely TTF diethyl ester(TTFDE),TTF tetramethyl ester(TTFTM),and TTF tetraethyl ester(TTFTE),are prepared and their energy storage properties are evaluated.It has been found that the redox potential and solubility of these TTF derivatives in conventional carbonate electrolytes increases with the number of ester groups.The battery with a catholyte of 0.2 mol L^(-1) of TTFTE delivers a specific capacity of more than 10 Ah L^(-1) at the current density of 0.5 C with two discharge voltage platforms locating at as high as 3.85 and 3.60 V vs.Li/Liþ.Its capacity retention can be improved from 2.34 Ah L^(-1) to 3.60 Ah L^(-1) after 100 cycles by the use of an anion exchange membrane to block the crossover of TTF species.The excellent cycling stability of the TIF esters is supported by their well-delocalized electrons,as revealed by the density function theory calculations.Therefore,the introduction of more and larger electron-withdrawing groups is a promising strategy to simultaneously increase the redox-potential and solubility of redox-active ma-terials for non-aqueous redoxflow batteries.

Carboxyl Ester Lipase Protects Against Metabolic Dysfunction-Associated Steatohepatitis by Binding to Fatty Acid Synthase

Carboxyl ester lipase(CEL),a pivotal enzyme involved in lipid metabolism,is recurrently mutated in obese mice.Here,we aimed to elucidate the functional significance,molecular mechanism,and therapeutic potential of CEL in metabolic dysfunction-associated steatohepatitis(MASH).Hepatocyte-specific carboxyl ester lipase gene(Cel)knockout(Cel^(DHEP))and wildtype(WT)littermates were fed with cholinedeficient high-fat diet(CD-HFD)for 16 weeks,or methionine-and choline-deficient diet(MCD)for three weeks to induce MASH.Liquid chromatography–mass spectrometry and co-immunoprecipitation were employed to identify the downstream targets of CEL.CD-HFD/MCD-fed WT mice received intravenous injections of CEL-adeno-associated viral,serotype 8(AAV8)to induce specific overexpression of CEL in the liver.We observed a decrease in CEL protein levels in MASH induced by CD-HFD or MCD in mice.Cel^(DHEP) mice fed with CD-HFD or MCD exhibited pronounced hepatic steatosis,inflammation,lipid peroxidation,and liver injury compared to WT littermates,accompanied by increased hepatic nuclear factor kappa-light-chain-enhancer of activated B cell(NF-jB)activation.Consistently,Cel knockdown in mouse primary hepatocytes and AML12 cells aggravated lipid accumulation and inflammation,whereas CEL overexpression exerted the opposite effect.Mechanistically,CEL directly bound to fatty acid synthase(FASN),resulting in reduced FASN SUMOylation,which in turn promoted FASN degradation through the proteasome pathway.Furthermore,inhibition of FASN ameliorated hepatocyte lipid accumulation and inflammation induced by Cel knockdown in vivo and in vitro.Hepatocyte-specific CEL overexpression using AAV8-Cel significantly mitigated steatohepatitis in mice fed with CD-HFD or MCD.CEL protects against steatohepatitis development by directly interacting with FASN and suppressing its expression for de novo lipogenesis.CEL overexpression confers a therapeutic benefit in steatohepatitis.

Design of the reactive dyes containing large planar multi-conjugated systems and their application in non-aqueous dyeing

The development of pollution-free dyeing technology, including anhydrous dyeing and non-aqueous dyeing technologies, has always been an important way and research hot in energy conservation and emission reduction. Designing new structural dye molecules is the key to water-saving dyeing processes.Herein, three reactive dyes were designed and synthesized, which contained large planar multiconjugated systems and multi-reactive groups. The designed reactive dyes are expected to have high affinity and high fixations in non-aqueous or small bath dyeing processes. The reactive dyes were applied in the decamethylcyclopentasiloxane(DMCS) reverse micelle dyeing for cotton fabric. High exhaustion rate of 99.35%, 98.10% and 98.80%, and fixation rate of 95.15%, 96.34% and 94.40% for three dyes, R1,R2 and R3, could be respectively obtained. The dyes can be fully utilized and had excellent dyeing performance, fastness and levelling properties under the revere micelle dyeing. The cotton fabric is like an oil-water separator in the dyeing process, where the dye micelles rapidly absorb and permeate into the cotton fibers. DMCS circulates around the fabric to transfer mass and energy. After dyeing, the solvent can be separated quickly and reused. The new reactive dyes containing large planar and multi-conjugated systems have potential application in green and sustainable dyeing technology with less wastewater and higher utilization.

Facile Preparation of Dopamine-Modified Magnetic Zinc Ferrite Immobilized Lipase for Highly Efficient Synthesis of OPO Functional Lipid

1,3-Dioleoyl-2-palmitoylglycerol(OPO)has been a hotspot of functional oils research in recent years,but due to the high cost of sn-1,3 specific lipase in enzymatic synthesis and the lack of biocatalyst stability,large-scale industrial application is difficult.In this study,the prepared magnetic ZnFe_(2)O_(4) was functionalized with dopamine to obtain ZnFe_(2)O_(4)@PDA,and the nano-biocatalyst ZnFe_(2)O_(4)@PDA@RML was prepared by immobilizing sn-1,3 specific lipase of Rhizomucor miehei lipase(RML)via a cross-linking method.The existence of RML on ZnFe_(2)O_(4)@PDA was confirmed by XRD,FTIR,SEM,and TEM.This strategy proved to be simple and effective because the lipase immobilized on magnetic nanoparticles could be quickly recovered using external magnets,enabling reuse of the lipase.The activity,adaptability to a high temperature,pH value,and operational stability of immobilized RML were superior to those of free RML.After optimizing the synthesis conditions,the OPO yield was 42.78%,and the proportion of PA at the sn-2 position(PA-Sn2)was 54.63%.After the first four cycles,the activity of ZnFe_(2)O_(4)@PDA@RML was not significantly affected.The magnetically immobilized lipase has good thermal stability,long-term storage stability,reusability,and high catalytic activity.It can be used as a green and efficient biocatalyst to synthesize the OPO functional lipid.

Conjugation of Candida rugosa lipase with hydrophobic polymer improves esterification activity of vitamin E in nonaqueous solvent

We described a novel polymer-lipase conjugate for high-efficient esterification of vitamin E using vitamin E and succinic anhydride as the substrates in nonaqueous media.In this work,the monomer,N-isopropylacrylamide(NIPAM),was grafted onto Candida rugosa lipase(CRL)to synthesize poly(NIPAM)(pNIPAM)-CRL conjugate by atom transfer radical polymerization via the initiator coupled on the surface of CRL.The result showed that the catalytic efficiencies of pNIPAM-CRL conjugates(19.5-30.3 L·s^(-1)·mmol^(-1))were at least 7 times higher than that of free CRL(2.36 L·s^(-1)·mmol^(-1))in DMSO.It was attributed to a significant increase in Kcat of the conjugates in nonaqueous media.The synthesis catalyzed by pNIPAM-CRL co njugates was influenced by the length and density of the grafted polymer,water content,solvent polarity and molar ratio of the substrates.In the optimal synthesis,the reaction time was shortened at least 7 times,and yields of vitamin E succinate by pNIPAM-g-CRL and free CRL were obtained to be 75.4%and 6.6%at 55℃after the reaction for 1.5 h.The result argued that conjugation with pNIPAM induced conformational change of the lid on CRL based on hydrophobic interaction,thus providing a higher possibility of catalysis-favorable conformation on CRL in nonaqueous media.Moreover,pNIPAM conjugation improved the thermal stability of CRL greatly,and the stability improved further with an increase of chain length of pNIPAM.At the optimal reaction conditions(55℃and 1.5 h),pNIPAM-g-CRL also exhibited good reusability in the enzymatic synthesis of vitamin E succinate and kept~70%of its catalytic activity after ten consecutive cycles.The research demonstrated that pNIPAM-g-CRL was a more competitive biocatalyst in the enzymatic synthesis of vitamin E succinate and exhibited good application potential under harsh industrial conditions.

Analyses of non-aqueous reactive polymer insulation layer in high geothermal tunnel

The scenario of geothermal tunnel is commonly observed around the world,and increases with the new constructions in the long and deep tunnels,for example in China.Tunnel insulation is generally divided into active and passive insulation.In passive insulation,it is an effective way to set low thermal con-ductivity materials as the thermal insulation layer as the choice of insulation material mainly depends on the thermal conductivity.Polymer is a kind of material with good geothermal performance,but there are relatively few studies.In this context,the transient plane source(TPS)method was used to measure the thermal conductivity of the developed polymer.Then,the temperature field of the high geothermal tunnel insulated by the non-aqueous reactive polymer layer was simulated.With the parametric analysis results,the suggestions for the tunnel layers were proposed accordingly.It revealed that the thermal conductivity of polymer first increases and then decreases with temperature.There are two rising sec-tions(?40e10?C and 20e90?C),one flat section(10e20?C)and one descending section(>90?C).It is observed the thermal conductivity of polymer increases with increase of the density of insulation layer and the density,and the thermal conductivity decreases when exposed to high temperatures.The temperature of the surrounding rocks increases with increase of the thermal conductivity and the thickness of polymer.Finally,a more economical thickness(5 cm)was proposed.Based on the parametric study,a thermal insulation layer with thermal conductivity less than 0.045 W/(m K),thickness of 5 cm and a density less than 0.12 g/cm 3 is suggested for practice.

Bound lipase:an important form of lipase in rice bran (Oryza sativa)

Rice bran residue possessed a steady lipase activity((26.68 ± 3.69)%)after its endogenous lipase was extracted continuously by phosphate buffer solution(PBS)for 24 h. T herefore, the aim of this research was to explore whether there exist any bound lipases in rice bran(Oryza sativa). Three physical treatments(grinding, homogenizing and ultrasound crush)and 6 enzymatic treatments(cellulase, hemicellulase, pectinase, complex cellulase, glucoamylase and α-amylase)were applied to rice bran in order to investigate this bound lipase. The relative catalytic activities of extraction supernatant and residue for pectinase group were(437.63 ± 22.54)% and(159.26 ± 2.12)%, respectively, which were significantly higher(P < 0.05)than other groups. This phenomenon demonstrated that lipase was the most likely to combine with pectin. Molecular simulation proved that pectin could combine with two rice bran lipases(lipase 315 and lipase 308)and cover the catalytic centers so as to prevent the lipases from encountering the substrate and inhibiting their catalytic activities. During combination, pectin could make the lipases more compact and reduce the solvent accessible surface area of lipases, which would make the lipases inactive to molecular interaction. In summary, part of rice bran lipase was proved to exist in bound form and combined with the pectin.

Novel Lipase from Golden Pompano(Trachinotus ovatus)Viscera:Purification,Characterization,and Application in the Concentrating of n-3 Polyunsaturated Fatty Acids

Lipases have been widely applied in a variety of industrial fields,such as food,pharmaceuticals,biofuels,and biotechnology.Recent years have witnessed a great interest in modifying lipids for the production of triacylglycerols enriched with n-3 polyunsaturated fatty acids(PUFAs).Here,a novel salt-tolerant,organic solvent-stable,and bile salt-activated lipase was purified from golden pompano(Trachinotus ovatus)viscera,which was named as golden pompano lipase(GPL).GPL had a specific activity of 57.2U mg^(-1)with an estimated molecular weight of 14 k Da,exhibited optimal activity at 40℃a nd pH 8.0,and showed K_(m)and V_(max)of 40.16μmol L^(-1)and 769.23μmol L^(-1)min^(-1),respectively.GPL activity was enhanced by Mn^(2+)and sodium deoxycholate.It was active in organic solvents,including methanol,ethanol,chloroform,and hexane.GPL also showed a good salinity tolerance of up to 1 mol L^(-1).n-3PUFA enrichment in the glyceride fraction of golden pompano oil was performed by GPL-catalyzed hydrolysis and yielded a total PUFA concentration of 56.99%.EPA,DHA,and DPA were enriched by 10.4-,3.2-,and 1.8-fold of their initial levels,respectively.This study recognized the industrial applicability of GPL to prepare enriched C_(20-22)n-3 PUFA.

Encapsulation of lipases on coordination polymers and their catalytic performance in glycerolysis and esterification

In this study,lipases of CALB(Candida antarctica lipase B),TLL(Thermomyces lanuginosa lipase),RML(Rhizomucor miehei lipase),CALA(Candida antarctica lipase A)and LU(Lecitase?Ultra)were encapsulated into the nucleotidehybrid metal coordination polymers(CPs)for diacylglyerols(DAG)preparation.Guanosine 5'-monophosphate(GMP)and adenosine 5'-monophosphate(AMP)were used as coordinating molecules,and metal ions of Fe^(3+),Ba^(2+),Mn^(2+),Ni^(2+)and Cr^(3+)were applied to prepare matrix.Results indicated that,besides Ba^(2+)with AMP,all other metal ions can coordinate with AMP and GMP to generate CPs.In addition,the AMP/Ni was amorphous when standing temperature was 4℃,while it was crystalline when standing temperature was from 30 to 180℃.DAG content from 47.55%to 64.99%was obtained from glycerolysis by CALB@GMP/Ba,RML@GMP/Ba,TLL@GMP/Ba,RML@GMP/Mn and TLL@GMP/Mn.Additionally,CALB@GMP/Fe showed selectivity towards DAG formation in the esterification and DAG content up to 61.88%was obtained.

Changes in Lipoprotein Lipase in the Heart Following Diabetes Onset

Due to its constant pumping and contraction, the heart requires a substantial amount of energy, with fatty acids (FAs) providing a major part of its adenosine triphosphate (ATP). However, the heart is incapable of making this substrate and attains its FAs from multiple sources, including the action of lipoprotein lipase (LPL). LPL is produced in cardiomyocytes and subsequently secreted to its heparan sulfate proteoglycan (HSPG) binding sites on the plasma membrane. To then move LPL to the endothelial cell (EC) lumen, glycosylphosphatidylinositol-anchored high-density lipoprotein-binding protein 1 (GPIHBP1) attaches to interstitial LPL and transfers it to the vascular lumen, where the LPL is ready to perform its function of breaking down circulating triglycerides (TG) into FAs. The endo-β-glucuronidase heparanase (Hpa) is unique in that it is the only known mammalian enzyme to cleave heparan sulfate (HS), thereby promoting the abovementioned release of LPL from the cardiomyocyte HSPG. In diabetes, it has been suggested that changes in how the heart generates energy are responsible for the development of diabetic cardiomyopathy (DCM). Following moderate diabetes, with the reduction in glucose utilization, the heart increases its LPL activity at the vascular lumen due to an increase in Hpa action. Although this adaptation might be beneficial to compensate for the underutilization of glucose by the heart, it is toxic over the long term, as harmful lipid metabolite accumulation, along with augmented FA oxidation and thus oxidative stress, leads to cell death. This coincides with the loss of a cardioprotective growth factor—namely, vascular endothelial growth factor B (VEGFB). This review discusses interconnections between Hpa, LPL, and VEGFB and their potential implications in DCM. Given that mechanism-based therapeutic care for DCM is unavailable, understanding the pathology of this cardiomyopathy, along with the contribution of LPL, will help us advance its clinical management.

Prokaryotic Expression of Pseudomonas Aeruginosa Lipase Gene

[Objective] The aim of this study was to investigate the prokaryotic expression of pseudomonas aeruginosa Lipase gene.[Method]Lipase gene was amplified by PCR from the genome DNA of pseudomonas aeruginosa,and its nucleotide sequence was determined.The prokaryotic expression vector of Lipase gene was constructed by the gene recombination technique.The protein expression was induced for 4 hours by IPTG with the final concentration of 1.0 mmol/L,and then SDS-PAGE electrophoresis was analyzed.[Result]The sequence of mature peptides in Lipase gene cloned from pseudomonas aeruginosa had a 99.36% homology with that of pseudomonas aeruginosa lipase submitted in NCBI,so the prokaryotic expression vector of Lipase gene pET32a-Lip was successfully constructed.Furthermore,the results of SDS-PAGE electrophoresis showed that the target gene was expressed highly and effectively.[Conclusion]The cloned pseudomonas aeruginosa lipase with its signal peptide could be normally expressed in E.coli and also used for further study.

Genetic Screening of the Lipoprotein Lipase Gene for Mutations in Chinese Subjects with or without Hypertriglyceridemia

Objective： To investigate the association between the mutations in lipoprotein lipase gene and hypertriglyceridemia （HTG）. Methods： The lipoprotein lipase （LPL） gene was screened for mutations in 386 Chinese subjects with （108 cases in the HTG group） or without HTG （278 cases in the control group）, by single-strand conformation polymorphism （SSCP） analysis and DNA sequencing. Results： One novel silent mutation L103L, one missense mutation P207L, three splicing mutations Int3/3＇ -ass/C（-6）→T, and the common S447X polymorphism has been identified in the whole coding region and exon-intron junctions of the LPL gene were examined. Heterozygous P207L found in the HTG group was the first case reported in Asia and subsequently another P207L heterozygote was found in the proband＇s family, all of which suggested that P207L was one of the causes of familial combined hyperlipidemia, but was not so prevalent as that in French Canadian. Int3/3＇-ass/C（-6）→T was found in both groups in the present study although it was regarded as a pathogenic variant to HTG earlier on. Moreover about the beneficial polymorphism S447X, there was also some supportive evidence that the levels of triglycerides （TG） in S447X carriers were significantly lower than noncarders in the subjects without HTG. Conclusions： The association between the LPL variants and HTG is quite complicated and versatile, genotyping of LPL in a larger-scale screening should be necessary and justifiable.

联合检测血清Lipase、CRP和IL-6在急性胰腺炎诊断和预后判断中的价值

目的 评价联合检测脂肪酶 (Lipase)、白细胞介素 6 (IL 6 )和C 反应蛋白 (CRP)是否能够快速诊断和有效预后急性胰腺炎。方法 检测 4 0例非胰腺炎急腹症病人 ,4 0例急性胰腺炎患者 (包括 2 5例轻型急性胰腺炎患者和 15例重症急性胰腺炎患者 )和 4 0例健康控制组人员的血清Lipase、IL 6、CRP水平。 结果 Lipase(判定点设在 4 5 0u/L)可以正确区分 97%的急性胰腺炎患者和其它急腹症患者 ,有 2例急性胰腺炎患者Lipase低于 4 5 0u/L而未能正确区分 ,阳性预测值为 97% ,阴性预测值为 95 %。IL 6 (判定点设在 3 7μg/L) ,可以正确区分重症胰腺炎和轻度胰腺炎 ,敏感性为 10 0 % (15 / 15 ) ,特异性为 87% (2 0 / 2 3) ,阳性预测值为 88% ,阴性预测值为 10 0 % ,可以对急性胰腺炎的病情程度进行准确分级。CRP(判定点设在 6mg/L)显示预后效率低于IL 6 ,敏感性为 87% (13/ 15 ) ,特异性为 4 8% (11/ 2 3) ,阳性预值为 5 2 % ,阴性预值为 85 %。结论 联合检测Lipase、CRP和IL 6可以快速诊断急性胰腺炎和有效预后病情 ,指导临床治疗。

Advances in Application of Non-aqueous Phase Enzymatic Catalysis in Food Additive Production

Non-aqueous phase enzymatic catalysis technology has been widely ap- plied in the area of food additives production. This paper reviewed the types of re- action medium of non-aqueous phase enzymatic catalysis reaction, introduced the application of non-aqueous phase enzymatic catalysis technology in catalysis of L-ascorbic （isoascorbic） acid esters, short-chain acid esters, sugar esters, vitamin A esters, vi- tamin E esters, and other food additives, and finally predicted the prospects of non- aqueous phase enzymatic catalysis technology.

偏甘油酯脂肪酶Lipase G50催化酯化法制备甘油二酯

利用偏甘油酯脂肪酶Lipase G50催化甘油和脂肪酸酯化反应合成甘油二酯。探讨了酶加量、底物摩尔比、反应温度及加水量对酯化反应的影响。结果表明最佳反应条件为:脂肪酶Lipase G50加量为350 U/g,甘油和脂肪酸的摩尔比5∶1,加水量为底物总质量的5%,反应温度30℃,反应时间24 h。在最佳反应条件下脂肪酸的酯化率为75.02%,甘油二酯的含量达到44.74%,产物中没有甘油三酯生成。

铜绿假单胞菌脂肪酶Lipase基因的原核表达

[目的]对铜绿假单胞菌脂肪酶Lipase基因进行原核表达。[方法]利用PCR方法从铜绿假单胞菌基因组DNA中扩增得到脂肪酶基因,测定其核苷酸序列,利用基因重组技术构建脂肪酶基因的原核表达载体,加IPTG至终浓度为1.0 mmol/L诱导蛋白表达4 h,并进行SDS-PAGE电泳。[结果]从铜绿假单胞菌中克隆的脂肪酶基因成熟肽的序列,与NCBI上所递交的铜绿假单胞菌脂肪酶序列同源性很高,达99.36%。成功构建了脂肪酶基因的原核表达载体pET32a-Lip,进一步SDS-PAGE电泳结果显示目的基因得到高效表达。[结论]克隆的铜绿假单胞菌脂肪酶带有自身的信号肽,也可以在大肠杆菌中正常表达,可以用于进一步的研究。

固定化脂肪酶Lipase G 50催化合成甘油二酯的研究

以D380、CAT600、AB-8三种大孔树脂为载体,采用物理吸附法,对偏甘油酯脂肪酶LipaseG50进行了固定化,并利用其催化脂肪酸和甘油酯化合成甘油二酯。结果表明,采用D380固定的脂肪酶酶活最高,用此固定化酶催化反应的最佳条件为:甘油和脂肪酸的摩尔比5∶1,固定化酶酶加量为底物总质量的7.5%,反应温度35℃,在此条件下经过96h的反应,酯化率为76.39%,甘油二酯的含量为43.89%,没有甘油三酯生成。固定化酶重复使用5个批次后酯化率可达65.76%,甘油二酯的含量达到38.45%,具有良好的重复使用稳定性。

器壁固定化脂肪酶(Pseudomonas cepacia lipase)的非水活性与稳定性

许多脂肪酶在有机体系中表现出催化作用,可用于绿色有机合成.但其催化活性和稳定性明显低于水/油(有机相)界面上的表现.为了提高脂肪酶在有机反应体系中的活性和稳定性,依据脂肪酶的界面活化机制,以水为酶蛋白构象优化剂、羧甲基纤维素为赋形剂,通过物理吸附的方式,将典型的假单胞菌脂肪酶(Pseudomonas cepacia lipase)固定在锥形瓶的内壁上,形成简易的生物反应器.为方便检测器壁固定化酶促反应动力学,选择特征吸收为640 nm的生化指示剂2,6-二氯靛酚为反应底物,乙酸乙烯酯为酰化试剂,丙酮为溶剂.光谱检测表明,催化反应0.5 h后,器壁固定化脂肪酶转化底物的能力是脂肪酶粉的6倍.在每次催化5 h共10次的循环催化中,器壁固定化脂肪酶的催化活性平均每次仅降低3.2%,而酶粉降低11.8%.结果表明,该器壁固定化脂肪酶的活性和稳定性相对于酶粉明显提高,这将为通过固定化有效提高脂肪酶的非水催化作用提供重要的参考.

中国野桑蚕抗病毒蛋白基因(Lipase)的克隆与活性鉴定

从中国野桑蚕幼虫中肠细胞克隆获得了抗家蚕核型多角体病毒BmNPV的脂肪酶基因(Lipase)cDNA(GenBank:AY945212)。该基因cDNA大小906 bp,编码301个氨基酸,蛋白质分子质量约为28.9 kD。进一步克隆了其全长基因组,结果表明该基因由2 147 bp组成,包含4个外显子和3个内含子。该基因在野桑蚕体内的表达具有组织特异性,仅限于野桑蚕中肠组织表达,且在幼虫龄中表达水平较高,而在幼虫眠期和熟蚕期几乎没有表达。通过基因体外表达获得的重组蛋白Lipase,能够有效抑制BmNPV病毒对家蚕的感染,说明该蛋白具有较强的抗BmNPV的生物学活性。