CAOSA-extracted lignin improves enzymatic hydrolysis of cellulose

The conversion of biomass into sugar platform compounds is very important for the biorefinery industry.Pretreatment is essential to the biomass of the sugar platform,however,the lignin obtained by pretreatment,as a key part of lignocellulose,generally has a passive effect on the enzymatic hydrolysis of cellulose into sugars.In this study,p-TsOH(p-toluenesulfonic acid),DES(Deep eutectic solvent)and CAOSA(cooking with active oxygen and solid alkali)pretreatment ways were used to fraction lignin from bamboo biomass.After CAOSA treatment,the hydrolysis efficiency of the pulp was 95.57%.Moreover,the effect of different treatment methods on lignin properties was studied and the promotion effect of lignin was investigated by adding it to the cellulose enzymatic hydrolysis system.In this work,the results showed that CAOSA-extracted lignin with lower D(1.31-1.25)had a better adsorption effect on the enzyme protein.p-TsOH-extracted lignin with a larger S/G ratio enhanced the inhibition of enzymatic hydrolysis.In addition,the presence of-COOHs in lignin could reduce its inhibitory effect on cellulose saccharification.

Effects of β-cyclodextrins on the enzymatical hydrolysis of chiral dichlorprop methyl ester

The effect of β-cyclodextrins(β-CDs) on the enzymatical hydrolysis of chiral dichlorprop methyl ester (DCPPM) was studied. Four kinds of β-cyclodextrins(β-cyclodextrin, Partly methylated-CD(PM-β-CD), hydroxypropyl-cyclodextrin(HP-β-CD) and carboxymethyl-cyclodextrin(CM-β-CD)) were used. Compared with 100% DCPPM in the absence of β-cyclodextrins, the activity of lipase decreased with the increase of β-cyclodextrin and PM-β-cyclodextrin. However, CM-β-cyclodextrin stimulated the lipase activity. The inhibition effect of β-cyclodextrin and PM-β-cyclodextrin on the hydrolysis of DCPPM is affected by many factors other than degree of the methylation blocking the active site of lipase. UV-Vis and Fourier transform infrared(FTIR) spectroscopy studies of the complexation of aqueous DCPPM with β-CDs provide fresh insight into the molecular structure of the complex and explain the effects of β-CDs on enzymatical hydrolysis of chiral DCPPM. Data showed that inclusion complexes had formed by complexation of the CM-β-CD with DCPPM and the solubility of DCPPM was increased in water, which leaded to the increased lipase activity.

Xylo-Oligosaccharide Preparation through Enzyme Hydrolysis of Hemicelluloses Isolated from Press Lye

The emerging food additive, xylo-oligosaccharide(XOSs), was prepared through enzymatic hydrolysis of hemicelluloses isolated from press lye. Two of the three experimental enzyme preparations presented favourable effects, while the other one consisting of the nominal enzyme preparations with high enzyme activity was found to have poor catalytic effects. The conversion of xylan exceeded 40% and the selectivity for XOSs reached 90% when the temperature, hemicellulose concentration, dosage of enzymes, and hydrolysis time were 40?C, 100 g/L, 1 ku/g, and 4 h, respectively. Xylo-oligosaccharide preparation through enzymatic hydrolysis of hemicelluloses isolated from press lye was proved to be a feasible process to utilize the by-product of the lye regeneration, which will substantially improve the economy of the lye regeneration and recycling.

Extraction of Amino Acids from Excess Activated Sludge by Enzymatic Hydrolysis

A study was undertaken to investigate the production of amino acids from excess activated sludge (EAS) by enzymatic hydrolysis. Firstly, the protein was extracted from EAS. Secondly, the protein solution was further hydrolyzed under free enzyme or immobilized enzyme. The reversed phase high performance liquid chromatography (RP-HPLC) and inductively coupled plasma emission spectrometer (ICP) were applied to determine the contents of amino acids and heavy metals, respectively. The effects of enzyme/substrate(E/S), pH, temperature, and reaction time were investigated in detail. The results indicated that, the optimum conditions for protein hydrolysis were temperature 55℃, pH 10, E/S 9 g/L, and reaction time 8 h, and the highest yield of amino acids was more than 10 g/100 g dry sludge (DS) under free enzyme. Moreover, the security and nutrition were taken into consideration. There were seven kinds of essential amino acids and ten non-essential amino acids in the raw amino acid (RAA) solution, and the contents of heavy metals were lower, living up to Hygienical standard for feeds (China). This technology widens the source of amino acids and makes the extraction of amino acids from EAS more economic and effective.

Response Surface Optimization of Enzymatic Hydrolysis of Sugar Beet Leaves into Fermentable Sugars for Bioethanol Production

Sugar beet leaves are the major crop waste from sugar beet production, while the unused leaves contain a high number of sugars and polysaccharides. The effects of different enzyme products (cellulase, Cellic CTec2;xylanase, Cellic HTec2;and pectinase, Pectinex Ultra SPL) were determined during high-solids enzymatic hydrolysis of sugar beet leaves at 10% total solids (TS) content. Response surface methodology was used to study the effects of enzyme loadings during the hydrolysis of sugar beet leaves for producing fermentable sugars. It was found that both cellulases and pectinases are important enzymes for the hydrolysis of sugar beet leaves. Enzyme loading and reaction time were important factors. Based on the amount of sugars released, a maximum sugar conversion of 82% was achieved after 72 h of hydrolysis using 30 filter paper unit (FPU) g-1 glucan for cellulase and 150 polygalacturonase unit (PGU) g-1 polygalacturonic acid for pectinase, or 37 FPU g-1 glucan for cellulase and 100 PGU g-1 polygalacturonic acid for pectinase. The corresponding sugar yield and sugar concentration were 0.35 g·g-1 TS, and 35 g·l-1, respectively. Sugar conversion ranged from 59% - 70%, 68% - 80%, and 74% - 82% after 24 h, 48 h, and 72 h of hydrolysis depending on the design conditions.

Kinetic Dependences of Two-Stage Dilute Acid and Enzyme Hydrolysis of Paulownia tomentosa

The sugars potential ofPaulownia tomentosa is estimated by dilute acid pretreatment and cellulase hydrolysis. The kinetics of dilute （1%） sulfuric acid hydrolysis is studied at temperatures of 100 ℃, 120 ℃ and 130 ℃, while the kinetics of the subsequent enzyme hydrolysis is examined at a temperature of 50 ℃ and reaction time varied from 60 to 300 min using cellulase complex NS 50013 and β-glucosidase N S 50010. The reducing sugars formation is modeled as a pseudo-homogeneous first order reaction in view of the kinetics of dilute sulfuric acid hydrolysis. The results obtained indicate that the reaction proceeds in an energetically homogeneous system （E = const） providing identical accessibility of the reagent to the hydrolyzing sites （A = const）. The enzyme hydrolysis kinetics follows heterogeneous catalytic mechanism. The process is described by an exponential kinetic equation, which is well recognised in case of processes on uniformly inhomogeneous surfaces. The current rate decreases significantly probably because of exhaustion of the available active sites on the surface and steric hindrances due to the presence of lignin. This investigation provides information of importance for the fermentation step of the bio-ethanol production process.

Study of the Effect of Different Solids Load on the Optimum pH during Enzymatic Hydrolysis of Steam Exploded Corn Stover

The understanding of enzymatic saccharification of pretreated lignocellulosic material is of great importance. There are several important commercially available enzymes in the market that are used for this purpose. The conditions of pH and temperature performance of any particular enzyme are very well defined and it is clearly indicated by its manufacturer and it depends on the type of enzyme or enzymes in the complex pool. It is well know that commercial cellulases work best at pH around 4.8-5.0 and as a consequence this is widely used in the industry and the literature. In this study it was found that optimum pH of cellulases is different than that recommended by its manufacturer at higher solids load saccharification. The optimum pH changes depending on the consistency or solids loads of the matrix where the enzyme is acting upon. Steam exploded corn stover was tested with cellulases and xylanases at different pH, consistencies and ionic strength. Results showed that the optimum pH at lower consistency （1% w/w） is the same as the one recommended by the manufacturer and in the literature; however at higher consistency the value obtained was higher （pH 5.5 to pH 6.5） instead ofpH 4.8. The difference could represent up to 30-50% higher yields and hence of great importance for the economics of second generation fuel production. An explanation of this behavior could be associated with the Donnan effect theory. This effect indicates that the presence of charged groups in the fiber matrix creates a pH gradient within the slurry. If the charged groups are negatively charged this would create a local or internal pH lower than the surrounding liquid pH. This could explain why by reducing the concentration of H^＋ higher enzymatic conversion yields were observed.

Immobilization in Spheres of a Cocktail Rich in Xylanase Produced by the Fungus <i>Fusarium sp</i>. EA 1.3.1 for Hydrolysis of Sugarcane Bagasse

Second generation ethanol is produced from the degradation of lignocellulosic biomass using enzymes as catalysts, with emphasis on xylanases. These biocatalysts are often costly, but stable at high temperatures, and their reuse is of great value, so the immobilization of the enzymes can increase their applicability on an industrial scale. We sought to immobilize a cocktail rich in xylanase produced by the fungus Fusarium sp. EA 1.3.1 in alginate spheres, optimize the immobilization method, characterize the immobilized derivatives, improve their physical-chemical characteristics, and perform the hydrolysis of sugarcane bagasse to release sugars. The Fusarium sp. EA 1.3.1 has been identified and used for cocktail rich in xylanase production that was immobilized in alginate spheres. During this process, the drip equipment, and the concentration of the solutions of sodium alginate and calcium chloride were evaluated. The best results were obtained with the glass rod and with concentrations of 3.14% and 2.10% for the solutions, respectively. The apparent optimum conditions of pH and temperature reaction were studied, and the values of pH 6.5 and 60°C were obtained. The immobilized conjugate also presented greater stability at this temperature than that of the soluble cocktail. The conjugate could be recycled up to six times, and its activity was maintained after 75 days of storage. Finally, the hydrolysis in natural sugarcane bagasse was achieved, and greater amounts of reducing sugars were obtained in the reaction with the conjugate. Thus, the cocktail rich in xylanase produced by the fungus Fusarium sp. EA1.3.1 was successfully immobilized on alginate spheres and possesses the potential to be used as a catalyst in industrial processes such as the lignocellulosic ethanol industry.

Determination of External Mass Transfer Model for Hydrolysis of Jatropha Oil Using Immobilized Lipase in Recirculated Packed-Bed Reactor

In this study, a simple and effective technique for establishing an external mass transfer model in a recirculated packed-bed batch reactor (RPBBR) with an immobilized lipase enzyme and Jatropha oil system is presented. The external mass transfer effect can be represented with a model in the form of Colburn factor JD = K Re-(1–n). The value of K and n were derived from experimental data at different mass flow rates.The experiment shows an average increment of 1.51% FFA for calcium alginate and 1.62% FFA for carrageenan after the hydrolysis took place. Based on different biopolymer material used in immobilized beads, JD = 1.674 Re-0.4 for calcium alginate and JD = 1.881 Re-0.3 for k-carrageenan were found to be adequate to predict the experimental data for external mass transfer in the reactor in the Reynolds number range of 0.2 to 1.2. The purposed model can be used for the design of industrial bioreactor and scale up. Besides, the external mass transfer coefficients for the hydrolysis of Jatropha oil reaction and the entrapment efficiency for the two biopolymer materials used were also investigated.

Investigation of the Interaction Mechanism between Lignin Structural Units and Enzyme

The effect of lignin structural units on enzymatic hydrolysis of lignocellulosic biomass was investigated,especially the inhibitory role of lignin in non-productive adsorption with enzymes.Milled wood lignin(MWL)was isolated from different hardwoods of poplar,eucalyptus and acacia.The isolated lignin samples were characterized by elemental analysis,gel permeation chromatography,nitrobenzene oxidation and fourier infrared spectroscopy.The mechanism of lignin structural units on enzymatic hydrolysis of cellulose was studied by quartz crystal microbalance(QCM).The results showed that different structural units of lignin had different adsorption capacity for enzymes.The results of nitrobenzene oxidation indicated that the S/G ratio(S:syringyl-like lignin structures;G:guaiacyl-like lignin structures)of lignin of poplar was 0.99,that of eucalyptus was 1.92 and that of acacia was 1.34.According to the results of QCM,the adsorption capacity of the three lignin films was as follows:Poplar MWL(S/G ratio 0.99)<Acacia MWL(S/G ratio 1.34)<Eucalyptus MWL(S/G ratio 1.92).Eucalyptus MWL with higher degree of condensation and S/G ratio showed stronger affinity to enzymes and more non-productive adsorption with enzymes,resulting in less adsorption between enzymes and cellulose,and lower enzymatic hydrolysis efficiency.

Purification and Characterization of Angiotensin I Converting Enzyme Inhibition Peptides from Sandworm Sipunculus nudus

Three angiotensin I converting enzyme(ACE) inhibition peptides were isolated from sandworm Sipunculus nudus protein hydrolysate prepared using protamex. Consecutive purification methods, including size exclusion chromatography and reverse-phase high performance liquid chromatography(RP-HPLC), were used to isolate the ACE inhibition peptides. The amino acid sequences of the peptides were identified as Ile-Asn-Asp, Val-Glu-Pro-Gly and Leu-Ala-Asp-Glu-Phe. The IC_(50) values of the purified peptides for ACE inhibition activity were 34.72 μmol L^(-1), 20.55 μmol L^(-1) and 22.77 μmol L^(-1), respectively. These results suggested that S. nudus proteins contain specific peptides that can be released by enzymatic hydrolysis. This study may provide an experimental basis for further systematic research, rational development and clinical utilization of sandworm resources.

Study on Process Conditions of Preparation of Microporous Potatoes Starch by Complex Enzyme Method

[Objective] The technology of using c-amylase and glucoamylase to prepare microporeus potato starch was studied.[ Method ] Taking potato starch as raw materials, starch hydrolysis rate and the oil absorption as a measure of index, the influences of the reaction temperature, two enzymes proportion, the quantity of enzyme, the chroma of substrate, buffer solution pH and reaction time on microporous potato starch were inves- tigated. [ Result] The experimental results showed that the best technological conditions were reaction temperature 45 ℃, enzyme ratio （ glucoamy- lase/α-amylase）6, the quantity of enzyme （amount of enzyme and starch quality than） is 1.0%, the substrate quantity chroma of 0.14 g/ml, buffer solution pH 4, the reaction time 8 h. In such process condition, the oil adsorption rate of hydrolyzed potato starch was as high as 70.2%, starch hydrolytic ratio was 34.16%. [ Condmion] The study provided a basis for the development and utilization of microporous starch. Key words Microporous starch; Hydrolysis rate; Oil absorption rate; Preparation; Complex enzyme method; China

重组木聚糖酶的高密度发酵及其定向制备低聚木糖

为提高酶水解杨木木聚糖定向转化低聚木糖的效率,同时降低酶法制备低聚木糖的成本,围绕重组大肠杆菌(PET-PdoXyn10A-DE3)高密度发酵制备拟杆菌来源木聚糖酶PdoXyn10A的诱导表达条件和酶水解制备低聚木糖的工艺条件开展了研究。考察了在5 L发酵罐水平下诱导剂浓度、诱导光密度(OD_(600))值、诱导温度和诱导pH值等因素对PET-PdoXyn10A-DE3产重组木聚糖酶PdoXyn10A的影响,反应温度、pH值对玉米芯木聚糖酶水解过程中酶活力的影响,以及酶添加量、酶水解时间对杨木乙酸水解液制备低聚木糖的影响。研究结果表明:在诱导剂浓度0.25 mmol/L、诱导OD_(600)值55、诱导温度34℃和诱导pH值7.0的最佳诱导条件下,经高密度发酵重组酶酶活力可达362.67 U/mL,重组大肠杆菌生物量可达28.83 g/L。酶水解制备低聚木糖的最佳条件为酶反应温度40℃、pH值5.2、酶添加量12 U/mL和反应时间6 h,此条件下低聚木糖的量为3.21 g/L,其中木二糖、木三糖、木四糖、木五糖和木六糖的量分别为1.09、 0.97、 0.84、 0.18、 0.13 g/L,木糖为1.82 g/L。

发酵和酶解技术在猪蛋白原料开发中的应用研究

发酵和酶解技术是猪蛋白饲料原料开发中常用的生物处理手段,能显著提高饲料的营养价值,降低抗营养因子含量,并促进动物肠道消化吸收。尤其在蛋白饲料资源匮乏及非常规蛋白饲料资源利用率较低等背景下,发酵和酶解技术在猪蛋白原料开发中具有广阔的应用前景和潜力。文章主要阐述了发酵和酶解技术特点,总结了发酵、酶解及其协同处理原料的应用技术研究现状,并对发酵和酶解技术在应用中存在的问题和未来发展的方向进行了分析及展望。

基于响应面法优化双酶同步酶解的全豌豆乳的稳定性及营养特性研究

豌豆作为一种大宗豆类,具有营养价值高及低致敏性等特点,但全豌豆乳体系易絮凝失稳,限制其在食品中的应用。本文以脱皮豌豆为原料,采用高压均质耦合生物酶解(中温α-淀粉酶和纤维素酶)处理,通过离心沉淀率等指标,以及Box-Behnken设计优化酶解工艺条件,揭示最优工艺下全豌豆乳的稳定性和营养特性变化规律。结果表明,相较于传统过滤、单一酶解、双酶分步酶解等方法,中温α-淀粉酶和纤维素酶双酶同步酶解制备的全豌豆乳稳定性更优,最佳的酶解工艺参数为:中温α-淀粉酶:纤维素酶为4.5:5.5(酶活力比,U/g淀粉),添加总量为12 U/g,酶解时间为65 min,该条件下制得的全豌豆乳的离心沉淀率最低(27.70%),在不经过滤和不添加稳定剂的情况下,贮藏60 d内无明显的沉淀分层。与传统单体营养素复配工艺得到的豌豆乳相比,该优化工艺下制得的全豌豆乳稳定性显著提高,淀粉的消化程度降低了12.74%,蛋白质的消化程度提高了16.41%。研究结果为浓浆类的植物乳开发提供一定的理论指导。

不同酶解路线大米蛋白肽的制备、表征及抗氧化活性

为探究双酶不同酶解路线制得大米蛋白肽的性质差异,研究采用胰蛋白酶(A)和碱性蛋白酶(B)按不同酶解路线对大米蛋白进行酶解,制备了5种大米蛋白肽(A^(1)B^(1)、A^(1)B^(2)、A^(2)B^(1)、A^(1*)B^(2)、A^(2)B^(1*)),对其水解度、基本成分、氨基酸组成、微观结构、二级结构、分子量分布、风味和体外抗氧化活性等进行分析。结果表明,A^(2)B^(1)组的蛋白含量最高达到90.69%,肽含量高达72.73%;各路线的水解度大于17.60%,水解较为完全;微观结构均由不规则块状变为球体状,A1B2组和A^(1*)B^(2)组球体壁较厚,A^(2)B^(1)组和A^(2)B^(1*)组球体壁较薄,A^(1)B^(1)组为球体碎片;各路线的必需氨基酸含量比大米蛋白低,A1B2组必需氨基酸含量最高;二级结构以多种构象并存,各路线二级结构均以β-转角为主,占二级结构的44.62%~47.18%;各路线酶解产物多为低分子量的多肽,分子量低于5 k Da的多肽占92.09%~93.71%;A1B2样品鲜味最强,涩味最弱,A^(2)B^(1)样品咸味和苦味最弱;相比于A^(1)B^(1)组、A1B2组和A^(1*)B^(2)组,A^(2)B^(1)组和A^(2)B^(1*)组的抗氧化活性更强。通过对双酶不同酶解路线大米蛋白肽的性质研究,综合基本成分、肽含量、氨基酸组成、风味和抗氧化活性评价,A^(2)B^(1)组的品质最佳。

植物细胞壁多糖高效酶解技术及其在食品加工中应用研究进展

植物细胞壁多糖的结构异质性和复杂性会限制食品加工中植物营养素的释放,最终影响产品的感官品质、营养价值和货架稳定性。利用植物细胞壁多糖降解酶(plant cell wall polysaccharide-degrading enzymes,PCWPE)实现高效酶解是食品加工中克服包裹植物细胞复杂多糖壁屏障的关键步骤。PCWPE包括纤维素酶、半纤维素酶和果胶酶,可专一高效地水解植物细胞壁层中的糖苷键,显著改善产品感官风味、营养价值,提高多相体系稳定性,并提高产率等。近年来,PCWPE广泛用于饮料加工、植物营养素萃取、功能性糖制备,以及新兴可持续型植物基食品加工,成为食品绿色加工的研究热点。因此,本文就PCWPE酶解机制、高效酶解技术及其在食品工业中应用等领域的最新研究进行综述,以期为高品质植物基食品加工技术创新提供参考依据。

复合酶酶解法制备中华草龟皮胶原蛋白肽的工艺优化

该研究探讨了不同种类蛋白酶对中华草龟皮胶原蛋白酶解液的水解度和DPPH自由基清除率的影响,并进一步研究了复合蛋白酶对胶原蛋白的酶解效果。此外,通过正交试验优化了复合酶酶解条件。结果表明,由胰蛋白酶和碱性蛋白酶按1∶1组成的复合酶对龟皮胶原蛋白进行酶解,可显著提高酶解液的水解度和DPPH自由基的清除率(P<0.05);优化的复合酶酶解工艺为复合酶添加量5000 U/g、酶解pH值7.5、酶解温度50℃、酶解时间3 h,在该酶解工艺条件下,水解度达(51.19±2.45)%,DPPH自由基清除率达(51.78±2.21)%。影响复合酶酶解效果的主次顺序为酶添加量>酶解pH值>酶解时间>酶解温度。

陈皮体外预处理对柑橘黄酮含量和感官指标的影响

研究旨在探究菌发酵、酶解、菌酶协同3种体外预处理方法对陈皮营养价值的影响。试验利用发酵菌和消化酶对陈皮分别进行发酵、酶解、菌酶协同预处理,以柑橘黄酮含量和感官指标为比较标准选择最优的预处理方法和条件。结果表明:菌发酵和菌酶协同处理陈皮方法显著优于酶解处理方法。其中菌发酵处理组料液比10∶7时黄酮含量显著提高(P<0.05);接种量3%和5%间差异不显著(P>0.05),且都优于接种量7%(P<0.05);发酵时间之间差异不显著(P>0.05)。酶解组的最佳条件为加酶量0.5%、料液比10∶7;菌酶协同处理组菌接种量间差异不显著(P>0.05);料液比10∶7和10∶8之间差异不显著(P>0.05),且都优于料液比10∶6(P<0.05);酶添加量为0.5%时,陈皮中的柑橘黄酮含量显著高于其他添加量(P<0.05)。说明菌发酵、酶解、菌酶协同3种处理方法均能提高陈皮中的柑橘黄酮含量,其中最优工艺为菌酶协同法,加菌量5%、加酶量0.5%、料液比10∶7。