酶法水解谷朊粉工艺研究

对谷蛋白肽酶法制备工艺进行了研究.利用蛋白酶Alcalase可获得较高的水解度,其较优的工艺如下:底物浓度10%,加酶量为底物的0.5%,pH为8.75,水解温度60 ℃,水解时间90 min.酶解后期,添加蛋白酶Umamizyme进行复合酶水解,其产物具有多肽含量高、风味协调等特点.     

用普通纯水代替缓冲液时蔗渣酶法水解反应的考察

使用Onozuk RS型纤维素酶,以普通的城市自来水和纯水代替缓冲液,直接加热膨化甘蔗渣进行酶法水解实验研究,结果表明:所使用的各种水代替缓冲液时,蔗渣酶解还原糖得率基本不变,还原糖得率最高时的最适宜pH为4.2～4.9,当蔗渣浓度大于1％时,反应液的pH恰好处于最适宜pH范围内,还原糖得率最高的酶解反应温度为50℃。     

酶法降解植物纤维素技术研究

用正交试验法探讨了以麦秸为原料进行纤维素酶降解的工艺条件。正交试验的结果表明,影响麦秸纤维素降解的因素的主次顺序为A（酶添加量）＞B（底物浓度）＞E（时间）＞C（温度）＞D（pH值）,纤维素酶解麦秸纤维素的最佳组合为A3B1E3C3D2,即纤维素酶的添加量为0．2％,底物浓度为5％,反应时间为2h,反应温度50℃,pH5.0时为最佳条件。在比常规酶解法时间缩短12－30倍的条件下,能使纤维素降解葡萄糖的转化率达22．3％。     

不同纤维素原料超临界水解的研究

分别以稻草秸秆、经预处理的稻草秸秆、脱脂棉、微晶纤维素和定性滤纸为原材料,利用间歇式的超临界反应设备,在400℃的盐浴中进行木质纤维素的超临界水解,采用3,5-二硝基水杨酸(DNS)法对产物中的还原糖进行测定,研究反应时间对不同纤维素原料水解产糖的影响。结果表明:在超临界条件下,不同原料在较短的时间内还原糖含量均出现峰值,随着反应时间的延长还原糖产量呈现下降的趋势;稻秆、预处理后的稻秆、脱脂棉、微晶纤维素和定性滤纸的最大产糖量分别为7.42、9.05、12.55、18.01和14.24 g/L;与此对应的最佳反应时间分别为3.5、4、3、3、4 min;对应的最大还原糖产率分别为14.84%、18.10%、25.10%、36.02%、28.48%。     

胃蛋白酶水解绿豆分离蛋白的工艺

选用胃蛋白酶对绿豆分离蛋白进行酶法水解,考察了原料预处理条件、pH、温度、底物浓度等对酶解的影响,结果表明：原料预处理最适条件为沸水浴中90℃处理20min,在37℃、pH1．8、底物质量分数7％、酶量6000U／g条件下酶解180min,水解度（DH％）为19．86％,达到了制备小肽的水解度要求。实验证明,经过水解,绿豆分离蛋白各功能特性得到很好的改善。     

纤维素生物质新型水解技术的研究进展

纤维素生物质水解技术是生物质资源转化的关键技术之一,在传统的酸水解和酶水解技术基础上,近年来出现了一些新型的水解技术,它们一般都具有绿色高效、对环境友好等特点;回顾并综述了纤维素生物质水解技术的最新进展,并对纤维素生物质水解技术的发展研究方向提出了设想.     

酶法制备甲壳低聚糖研究的进展

甲壳低聚糖具有多种重要的生理活性,可作为食品添加剂、生物农药和新型药物,是低聚糖研发的新热点。与壳聚糖相比,由于多糖链缩短使其水溶性好、黏度低且容易吸收。本文对酶法制备甲壳低聚糖的催化剂种类和特性、生物反应器选用及其工艺优化的最新进展进行综述,对酶法生产甲壳低聚糖进行总结并展望未来的研发重点。     

不同来源家蝇幼虫蛋白粉的水解与抗氧化性

本研究比较不同来源、不同酶解物浓度的家蝇幼虫蛋白及其抗氧化活性。以来自猪粪源和鸡粪源家蝇幼虫为原料制备蛋白粉,用胰蛋白酶水解蛋白粉制备水解产物,以·OH和O_2~-·清除率为指标评价两种蛋白酶解物的抗氧化活性。结果显示,家蝇幼虫蛋白水解物在4 h达水解度最高值,其水解物的·OH清除率在5 h达到最大为59.02%,其水解物的O_2~-·清除率在4 h达到最大为73.24%;随着两种水解物浓度增加,其抗氧化效果越强,当猪粪源和鸡粪源家蝇幼虫酶解物浓度为10 mg/mL时,两者O_2~-·清除率达到最大分别为70%和80%;·OH清除率分别为45%和52%。由此可见,家蝇幼虫酶水解物对超氧阴离子、羟自由基均有清除能力,鸡粪源家蝇幼虫酶解物优于猪粪源。     

Enzymatic hydrolysis and simultaneous saccharification and fermentation of alkali/peracetic acid-pretreated sugarcane bagasse for ethanol and 2,3-butanediol production

The enzymatic digestibility of alkali/peracetic acid (PAA)-pretreated bagasse was systematically investigated. The effects of initial solid consistency, cellulase loading and addition of supplemental β-glucosidase on the enzymatic conversion of glycan were studied. It was found the alkali-PAA pulp showed excellent enzymatic digestibility. The enzymatic glycan conversion could reach about 80% after 24 h incubation when enzyme loading was 10 FPU/g solid. Simultaneous saccharification and fermentation (SSF) results indicated that the pulp could be well converted to ethanol. Compared with dilute acid pretreated bagasse (DAPB), alkali-PAA pulp could obtain much higher ethanol and xylose concentrations. The fermentation broth still showed some cellulase activity so that the fed pulp could be further converted to sugars and ethanol. After the second batch SSF, the fermentation broth of alkali-PAA pulp still kept about 50% of initial cellulase activity. However, only 21% of initial cellulase activity was kept in the fermentation broth of DAPB. The xylose syrup obtained in SSF of alkali-PAA pulp could be well converted to 2,3-butanediol by Klebsiella pneumoniae CGMCC 1.9131.     

Enzymatic hydrolysis of sugarcane bagasse and straw mixtures pretreated with diluted acid

Abstract

In Brazil, sugarcane biomass is generated in large amounts. Sugarcane bagasse and straw are considered as an important feedstock for renewable energy and biorefinery. This paper aims to study the generation of monosaccharides (C5 and C6) from sugarcane biomass via processing bagasse or straw and mixtures of both materials (bagasse:straw 3:1, 1:1 and 1:3). Samples were pretreated with sulfuric acid which resulted in approximately 90% of hemicellulose solubilization, corresponding to around 58 g L^{? 1} of xylose. Pretreated straw showed greater susceptibility to enzymatic hydrolysis in comparison to bagasse, as shown by glucose yields of 76% and 65%, respectively, whereas the mixtures showed intermediate yields. Thus, one strategy to balance sugarcane biomass availability and possibly increasing 2G ethanol production would be to use bagasse–straw mixtures in appropriate ratios according to market fluctuations. Untreated and pretreated samples were analyzed using X-ray diffraction, but there was no relationship to enzymatic hydrolysis.     

蛋白质的酶水解过程研究

进行了蛋白质酶水解过程的研究。结果表明木瓜蛋白酶对混合蛋白质的亲和力最强 ,而 1398蛋白酶的亲和力最弱。也表明作用位点和亲和力之间有一定的对应关系 ,Km值和作用位点氨基酸含量比例的相关系数为 0 .90 9。温度影响结果表明温度较低时温度升高加速水解反应过程处主要地位 ;当温度较高时 ,酶失活过程处主导地位。在一定水解时间内的讨论最适温度条件具有更明确的针对性 ,从本研究的采用胰酶 (胰蛋白酶和胰凝乳蛋白酶 )水解 4h的条件下 ,反应温度控制在45～ 5 0℃之间最适     

Enzymatic Hydrolysis of Esters of Alkali Labile Carotenols

Esters of alkali labile carotenols were hydrolyzed enzymatically with pig liver esterase in Tris-HCl buffer containing 10-85% methanol or acetone.

The natural acetates peridinin, fucoxanthin, 19'-butanoyloxyfucoxanthin, pyrrhoxanthin and synthetic actinioerythrol diacetate provided the corresponding carotenols in 85%, 45%, (5 + 5 + 30)%, 65% and (30 + 3)% of the recovered carotenoid with total pigment recoveries 60%, 73%, 88%, 52% and 66%, respectively.

(3RS, 3'RS)-Astaxanthin dipalmitate was converted enzymatically with lipase in low yield to the monopalmitate and free astaxanthin (5% + 6%, pigment recovery 93%) with a preferred hydrolysis of the S-ester. The (R,R:R,S:S,S) ratio of substrate dipalmitate and product astaxanthin changed from 1:2:1 to 1:5:3.     

蔗渣水解液发酵乙醇的研究

研究了酵母（Ｐｉｃｈｉａｓｔｉｐｉｔｉｓ）Ｙ７１２４在限制供氧条件下尽管反应初期葡萄糖消耗速率大于木糖,但在一定时间后,葡萄糖的消耗速率变慢,而木糖消耗速率变快直至耗尽的现象。建立了气升柱以Ｐ．Ｓｔｉｐｉｔｉｓ转化木糖为目的和以溢流柱Ｓａｃｈａｒｏｍｙｃｅｓｃｅｒｉｖｉｓｉａｅ转化残留葡萄糖为目的的串联发酵乙醇工艺,即流加５倍浓缩的蔗渣水解液,Ｄ＝０.１ｈ^－１,还原糖总利用率为９７.２％,酒精浓度为４６.５ｇ／Ｌ,生产率为４.１ｇ／Ｌ·ｈ。     

磁性Fe3O4微粒对葵花籽壳酶水解的影响研究

将磁化后的Fe3O4微粒添加于葵花籽壳酶水解过程中, 分析在不同的Fe3O4添加量和不同的添加方法下, 葵花籽壳酶水解过程中纤维素酶酶活﹑纤维素转化率及还原糖浓度的变化特征, 研究磁性Fe3O4微粒对纤维素酶水解葵花籽壳的影响。并通过考察酶水解反应前后水解液的表面张力值和pH值的变化, 探讨和分析磁性Fe3O4微粒作用下纤维素酶的磁效应机制。结果表明, 磁性Fe3O4添加量为0.5 g/L~2.0 g/L时, 对纤维素酶酶活的提高﹑还原糖浓度的增加和纤维素的转化在48 h后表现出较明显的促进作用。磁性Fe     

Pretreatment and Hydrolysis of Brewer's Spent Grains

Brewer's spent grains (BSG), the voluminous residue after mashing, contains on dry weight basis about 40–50 % polysaccharides. For the recovery of soluble carbohydrates from BSG different physical, thermal and enzymatic treatments were used to solubilize the polysaccharides in BSG. Heating by microwave radiation to 160 °C in the presence of 0.1 M HCl released 35 % of the material in the form of reducing sugar, indicating that about 80 % of the polysaccharides were hydrolyzed. Nevertheless, 0.1 M acetic acid will even solubilize 30 % of the material as oligosaccharides on a prolonged incubation when pretreating the spent grains by extrusion cooking. A combination of the enzymes Ceremix Plus MG and CelluPract AL 70 achieved an almost 25 % release of saccharides after 4 hrs of incubation at 50 °C. A combination of extrusion cooking and enzymatic hydrolysis seems to be a very promising procedure.     

Enzymatic separation of hardly separable mixtures of structural isomers

Lipase-meditated separation of six hardly separable mixtures of structural isomers was carried out. It has become apparent that the hydrolysis rate of the C(5)-acetoxyl group of methyl (±)-5-acetoxy-4-aryl-(2E)-pentenoate possessing the ortho-substituents in the aromatic ring was slower than that of the corresponding compound with no substituents at the ortho-position. The hydrolysis rate of the C(5)-acetoxyl group of methyl (±)-5-acetoxy-2-aryl-(3E)-pentenoate possessing a remote reaction site from the ortho-substituents in the aromatic ring was proved to be faster than that of methyl (±)-5-acetoxy-4-aryl-(2E)-pentenoate.     

白蜡虫卵蛋白酶解工艺的研究

本项目对白蜡虫(Ericerus pela)卵蛋白的酶解工艺进行了研究。通过正交试验确定木瓜蛋白酶为适宜的水解用酶,最佳用量为1.5%;酶解条件为酶解温度50℃,酶解pH值9.0,酶解时间24 h,原料与水比例为1∶20;试验结果还表明原料在酶解前经过预处理,蛋白水解率可提高20.7%,预处理条件为原料在20倍的1 mol/L盐酸溶液中,80℃恒温加热30 min;在确定的最佳条件下对白蜡虫卵进行预处理和酶解,蛋白水解率可达58.4%。