鱼肉蛋白酶解产物加工特性及抗氧化性评价

以鳕鱼为原料,分别用风味蛋白酶、动物蛋白复合酶、胰蛋白酶、碱性蛋白酶和木瓜蛋白酶进行酶解,研究其在不同酶解条件下,酶解产物的苦腥味、溶解性、热稳定性以及亚铁离子螯合力和DPPH自由基清除力的差别。结果表明：酶解产物均具有较好的溶解性和热稳定性体外试验有一定的亚铁离子螯合能力和DPPH自由基清除力,其中动物蛋白复合酶酶解产物抗氧化性显著高于其他酶的酶解产物,并具有较弱的苦腥味。     

酶解大豆蛋白的制备工艺研究及其在细胞培养中的应用研究

采用两种非动物源性蛋白酶水解大豆蛋白,以水解度为指标,对不同比例4种酶两两组合测试其水解度,选出水解最佳用酶;在单因素试验基础上,采用正交试验对酶解大豆蛋白的工艺条件进行优化,并将产物进行动物细胞的生长进行检测。结果表明:复合蛋白酶与碱性蛋白酶以等比例进行混合,其水解效果最佳;水解最佳工艺为:温度60℃、p H值7. 0和酶/底物(E/S)=1∶4(质量比),水解时间为4 h,其水解度为43. 7%。将酶解产物培养BHK-21细胞,并与Hypep1510进行对比,细胞生长状态良好,其细胞密度在120 h时最大,为3. 96×10~5cells/mL,与Hypep1510相比,最大细胞密度并无明显差异,其倍增时间为26. 2 h,高于阴性对照组与阳性对照组,且细胞形态基本未发生改变,表明酶解大豆蛋白所的产物能够缩短细胞倍增的时间,且具有一定的促细胞生长作用,为其在动物细胞大规模培养中的应用提供了理论依据。     

魔芋粉酶解产物与低聚果糖对双歧杆菌的促生长作用比较研究

由枯草芽胞杆菌以摩芋粉为底物经发酵培养获得的β-甘露聚糖酶酶活力达10U／ml,用该酶液水解魔芋粉制备含有低聚糖的魔芋粉酶解产物。在无碳源的GAM基础培养基中,添加不同量的魔芋粉酶解产物对双歧杆菌具有明显的促生长作用,其促生长作用与低聚果糖相当,均以2％的浓度增殖效果最明显,与不加低聚糖的对照组相比,活菌数可以提高几倍到十几倍。     

专利之窗

930008饲料复合酶-蛋白生产方法本发明的生产方法是将各种原料通过锤式粉碎机加以粉碎,并按比例混合,加水混匀,经灭菌、冷却接入固体微生物混合培养物进行发酵,并通过低温干燥,粉碎后得成品。其具有动物所需的活性复合酶和生长因     

复合淀粉酶酶解生淀粉机理探讨

以生土豆淀粉为原料,考察了复合生淀粉酶水解机制。发现单个糖化酶的酶解遵循Michaelis-Menten机制,而α-淀粉酶的酶解不遵循Michaelis-Menten机制;水解过程中复合酶酶解产物d[G]／dt的变化说明α-淀粉酶能很好地协同糖化酶水解生淀粉,其效果不仅仅是两者的简单相加。     

酶解法提取纯化虎杖提取物中自藜芦醇的工艺研究

本文对虎杖提取物中虎杖苷的酶解条件及苷元白藜芦醇的提取纯化工艺进行研究,以样品中自藜芦醇的含量为指标,对纤维素酶、β-葡萄糖苷酶、复合酶进行筛选,结果表明以复合酶的水解效率最高:采用正交实验对影响复合酶酶解的因素:加酶量、温度、酶解时间进行考察;并对酶解后提取物中自藜芦醇的提取纯化工艺进行研究.得出如下较理想的酶解条件和提取纯化工艺:虎杖提取物,加水(pH 5)10倍,加20%的复合酶,于50℃保温24 h;酶解后的提取物经水、乙醇-水、碱溶液分步溶解沉淀,得白藜芦醇粗品,含量可达65%,工艺稳定可行.     

微生物发酵中草药的研究现状

中草药作为天然传统药物,具有纯天然、无药残、无抗药性和毒副作用小等特点,在临床医疗和日常保健中被广泛使用。微生物发酵中草药过程中,中草药经微生物产生的酶作用后,细胞壁中的纤维素、木质素等物质被降解,其活性成分得以释放;中草药活性成分酶解为小分子物质,增强药效以利于机体消化吸收。部分中草药经发酵可以降低其毒性,减少毒副作用,甚至产生新活性物质。同时中草药中的某些成分可促进微生物的生长繁殖,由此可见中草药与微生物协同作用、相辅相成。本文从发酵中草药的优势、常用微生物、应用现状、存在的问题和关键因素等方面进行综述,并对中草药发酵的应用前景进行展望。相信随着发酵技术的成熟和中草药的现代化发展,微生物发酵中草药将具有更广阔的发展潜力和应用价值。     

褐藻寡糖生物法制备研究进展 *

褐藻寡糖(alginate oligosaccharides,AOS)是褐藻胶的降解产物,具有抗氧化、调节免疫、调节血脂、促进细胞生长等生理活性,应用范围广泛。现有的AOS 制备法主要分为物理法、化学法和生物法。介绍AOS的生物法制备包括酶解、微生物全细胞发酵和生物合成法,基因工程的应用在改造产褐藻胶裂解酶的菌株以提高生物法效率方面具有重要意义。此外,规模化的AOS生物法制备案例进行了科学引证,并展望了未来 AOS规模化制备的发展方向,以期为 AOS 的工业化制备和应用提供参考。     

酸解纤维素酒精发酵的毒性问题

目前 ,纤维素的酒精发酵主要有两种方法 :一种是酸水解法 ,另一种是酶解法。虽然经过 2 0多年研究 ,在纤维素的酶法水解方面有了一定进展[1,2 ] ,但是与酸法水解发酵相比较 ,仍存在很多不足之处 ,如 :纤维素的酶解效率不高 ,原料没有被充分利用 ,生产周期长 ,成本高。因此 ,纤维素酒精发酵在目前仍以酸法水解工艺为主。这一工艺已经比较成熟 ,目前生产中存在的主要问题就是关于水解产物对发酵微生物的“毒性问题” ,近年来 ,在这方面的研究较多 ,也取得了一定进展。1　纤维素酸解产物对发酵微生物的抑制作用1 1　纤维素类原料水解过程中各物…     

大豆分离蛋白不同酶解方式水解度与乳化性和起泡性关系

研究了大豆分离蛋白酶解产物水解度与乳化和起泡功能特性的关系。试验结果表明:大豆分离蛋白酶解产物起泡性随着水解度的增加而增加,不同酶处理液的起泡性以AS1.398酶解液最好,水解度为20%时起泡性达到了360±2.46%。研究还发现,乳化性随着水解度增加而逐渐下降,以双酶复合酶解液最差(DH=25%时乳化性最差,17.60±0.80m l.g-1)。     

The effect of gas double-dynamic on mass distribution in solid-state fermentation

The mass distribution regularity in substrate of solid-state fermentation (SSF) has rarely been reported due to the heterogeneity of solid medium and the lack of suitable instrument and method, which limited the comprehensive analysis and enhancement of the SSF performance. In this work, the distributions of water, biomass, and fermentation product in different medium depths of SSF were determined using near-infrared spectroscopy (NIRS) and the developed models. Based on the mass distribution regularity, the effects of gas double-dynamic on heat transfer, microbial growth and metabolism, and product distribution gradient were systematically investigated. Results indicated that the maximum temperature of substrate and the maximum carbon dioxide evolution rate (CER) were 39.5 °C and 2.48 mg/(h g) under static aeration solid-state fermentation (SASSF) and 33.9 °C and 5.38 mg/(h g) under gas double-dynamic solid-state fermentation (GDSSF), respectively, with the environmental temperature for fermentation of 30 ± 1 °C. The fermentation production (cellulase activity) ratios of the upper, middle, and lower levels were 1:0.90:0.78 at seventh day under SASSF and 1:0.95:0.89 at fifth day under GDSSF. Therefore, combined with NIRS analysis, gas double-dynamic could effectively strengthen the solid-state fermentation performance due to the enhancement of heat transfer, the stimulation of microbial metabolism and the increase of the homogeneity of fermentation products.     

Microbial biomass production from rice straw by fermentation with Penicillium janthinellum

Production of microbial biomass through fermentation of pretreated rice straw using Penicillium janthinellum (St-F-3B) is reported, with emphasis on the use of non-effluent generating pretreatment procedures. The fungus readily metabolized a rice straw substrate that had been subjected to alkali pretreatment by steaming at atmospheric pressure followed by the neutralization of the alkali. The crude protein content of the microbial biomass averaged 15–20%. The fermentation could be carried out in aerated-agitated fermenters using fertilizer grade nutrient salts to produce a biomass with 17.5% crude protein. When operated on a semicontinuous basis using 20% of the previous batch as inoculum, successive batches produced a biomass product with 12–19% crude protein content in 48 h. The problems of developing a technology for protein from agricultural residues with particular reference to developing countries are discussed.     

S-腺苷甲硫氨酸的研究进展

S-腺苷甲硫氨酸(SAM)是甲硫氨酸和三磷酸腺苷相结合的代谢物,广泛存在于动植物和微生物体内,参与40多种生化反应,主要作为三种代谢途径(转甲基、转硫基、转氨丙基)的前体,临床上被广泛用于治疗肝病、抑郁症、关节炎等。SAM的制备方法主要有化学合成法、酶促合成法、发酵法三种。化学合成的SAM是消旋体,需进行光学拆分,且存在产率低、原料L-高半胱氨酸价格昂贵和环境污染等问题。酶促合成法合成的SAM纯度高,但原料ATP成本太高。发酵法已成为目前生产SAM最常用的方法,欧洲利用发酵法生产SAM已实现了产业化,但国内的起步较晚,目前还处于实验室研究阶段。因此,应加强发酵法生产SAM的产业化关键技术研究。     

Fermentative production of L-glycerol 3-phosphate utilizing a Saccharomyces cerevisiae strain with an engineered glycerol biosynthetic pathway

Interest in L-glycerol 3-phosphate (L-G3P) production via microbial fermentation is due to the compound's potential to replace the unstable substrate dihydroxyacetone phosphate (DHAP) in one-pot enzymatic carbohydrate syntheses. A Saccharomyces cerevisiae strain with deletions in both genes encoding specific L-G3Pases (GPP1 and GPP2) and multicopy overexpression of L-glycerol 3-phosphate dehydrogenase (GPD1) was studied via small-scale (100 mL) batch fermentations under quasi-anaerobic conditions. Intracellular accumulation of L-G3P reached extremely high levels (roughly 200 mM) but thereafter declined. Extracellular L-G3P was also detected and its concentration continuously increased throughout the fermentation, such that most of the total L-G3P was found outside the cells as fermentation concluded. Moreover, in spite of the complete elimination of specific L-G3Pase activity, the strain showed considerable glycerol formation suggesting unspecific dephosphorylation as a mechanism to relieve cells of intracellular L-G3P accumulation. Up-scaling the process employed fed-batch fermentation with repeated glucose feeding, plus an aerobic growth phase followed by an anaerobic product accumulation phase. This produced a final product titer of about 325 mg total L-G3P per liter of fermentation broth.     

Optimization of sodium percarbonate pretreatment for improving 2,3-butanediol production from corncob

Sodium percarbonate (SP), a kind of alkaline strong oxidant, was applied to corncob pretreatment. The optimized pretreatment conditions were at 4% (w/v) SP concentration with solid-to-liquid (SLR) ratio of 1:10 treating for 4?hr at 60°C. This pretreatment resulted in 91.06% of cellulose and 84.08% of hemicellulose recoveries with 34.09% of lignin removal in corncob. The reducing sugar yield from SP-pretreated corncob was 0.56?g/g after 72?hr of enzymatic hydrolysis, 1.75-folds higher than that from raw corncob. 2,3-butanediol production by Enterobacer cloacae in simultaneous saccharification fermentation was 29.18?g/L using SP-pretreated corncob as a substrate, which was 11.12 times of that using raw corncob. Scanning electron microscope, X-ray diffraction, and Fourier transform infrared spectra analysis indicated that physical characteristics, crystallinity, and structure of corncob had changed obviously after SP pretreatment. This simple and novel pretreatment method was effective for delignification and carbohydrate retention in microbial production of 2,3-butanediol from lignocellulose biomass.     

用基因工程菌酶法和化学法制备-D-对羟基苯甘氨酸(英文)

D 对羟基苯甘氨酸 (D p HPG)是制备羟氨苄青霉素、羟氨苄头孢菌素和羟氨唑头孢菌素等β 内酰胺类抗生素的重要中间体 ,同时它也用于多种多肽类激素及农药的合成 .在D 对羟基苯甘氨酸的多种制备方法中 ,生物酶转化法具有原料易得、工艺简单、耗能少、产率高、成本低、光学纯度好、三废污染少等优势 .为利用生物酶转化法制备D 对羟基苯甘氨酸 ,首先用尿素、乙醛酸和苯酚合成底物D ,L 对羟基苯海因 ,然后利用D 海因酶基因工程菌E .coliBL2 1 pMD T7 dht细胞作酶源 ,进行底物D ,L 对羟基苯海因到中间体N 氨基甲酰 D 对羟基苯甘氨酸的酶法转化 ,最后用化学法将N 氨基甲酰 D 对羟基苯甘氨酸进一步转化为D 对羟基苯甘氨酸 .结果表明 ,底物D ,L 对羟基苯海因的收率为 60 % .8L体积的发酵小试实验表明 ,发酵 12h ,工程菌E .coliBL2 1 pMD T7 dht的海因酶活力为 30 0 0U L ,SDS 聚丙烯酰胺凝胶电泳薄层扫描结果显示海因酶表达量约占菌体总可溶性蛋白质的 60 % ,菌体收率为 6% .8L体积的海因酶转化实验表明 ,在 4 %底物D ,L 对羟基苯海因和 1%菌体 (湿重 )pH 9 0情况下 ,反应 5h ,D ,L 对羟基苯海因的转化率可达 96% .在酸性条件下 ,用NaNO2 将N 氨基甲酰 D 对羟基苯甘氨酸转化为D 对羟基苯甘氨酸 ,反应 2h ,转     

Evaluating factors that influence microbial synthesis yields by linear regression with numerical and ordinal variables

In the production of chemicals via microbial fermentation, achieving a high yield is one of the most important objectives. We developed a statistical model to analyze influential factors that determine product yield by compiling data obtained from engineered Escherichia coli developed within last 10 years. Using both numerical and ordinal variables (e.g., enzymatic steps, cultivation conditions, and genetic modifications) as input parameters, our model revealed that cultivation modes, nutrient supplementation, and oxygen conditions were the three significant factors for improving product yield. Generally, the model showed that product yield decreases as the number of enzymatic steps in the biosynthesis pathway increases (7-9% loss of yield per enzymatic step). Moreover, overexpression of enzymes or removal of competitive pathways (e.g., knockout) does not necessarily result in an amplification of product yield (P-value>0.1), possibly because of limited capacity in the biosynthesis pathway to accommodate an increase in flux. The model not only provides general guidelines for metabolic engineering and fermentation processes, but also allows a priori estimation and comparison of product yields under designed cultivation conditions.     

内皮细胞抑制素酵母工程菌的高密度发酵及产物纯化和活性分析

用 30升发酵罐研究了内皮细胞抑制素 (EDN)酵母工程菌P .pastorisGS115 (pPIC9K EDN)的高密度发酵工艺 ,摸索出发酵培养基 ,pH ,诱导时间等对菌体生长和基因表达的影响 .根据所确定的最适条件进行发酵 ,通过补料和甲醇诱导 4 8h后 ,工程菌GS115 (pPIC9K EDN)生物量的A60 0 值达到 2 5 0 ,分泌量为 15 0mg L .发酵液经StreamlineSP ,SepharoseSPFF离子交换柱和Sepharose HeparinHiTrap亲和柱纯化 ,产物纯度达 97%以上 ,回收率为 6 0 % .Western印迹结果表明 ,酵母工程菌GS115 (pPIC9K EDN)表达的重组人内皮细胞抑制素具有天然EDN的免疫原性 .MTT法和抑癌实验结果显示 :纯化产物能抑制人脐静脉内皮细胞的增殖并能抑制移植于小鼠的黑色素瘤的生长 ,其平均抑瘤率是 94 2 % .     

Microbial production of metabolites and associated enzymatic reactions under high pressure

High environmental pressure exerts an external stress on the survival of microorganisms that are commonly found under normal pressure. In response, many growth traits alter, including cell morphology and physiology, cellular structure, metabolism, physical and chemical properties, the reproductive process, and defense mechanisms. The high-pressure technology (HP) has been industrially utilized in pressurized sterilization, synthesis of stress-induced products, and microbial/enzymatic transformation of chemicals. This article reviews current research on pressure-induced production of metabolites in normal-pressure microbes and their enzymatic reactions. Factors that affect the production of such metabolites are summarized, as well as the effect of pressure on the performance of microbial fermentation and the yield of flavoring compounds, different categories of induced enzymatic reactions and their characteristics in the supercritical carbon dioxide fluid, effects on enzyme activity, and the selection of desirable bacterial strains. Technological challenges are discussed, and future research directions are proposed. Information presented here will benefit the research, development, and application of the HP technology to improve microbial fermentation and enzymatic production of biologically active substances, thereby help to meet their increasing demand from the ever-expanding market.     

以苯丙氨酰-tRNA合成酶为靶点的新型抗结核药物高通量筛选模型的建立和应用

【目的】建立结核分枝杆菌PheRS抑制剂高通量模型,并运用此模型筛选化合物和发酵液样品。【方法】克隆和表达结核分枝杆菌PheRS蛋白并优化其酶活测定方法,在此基础上建立结核分枝杆菌PheRS抑制剂高通量筛选模型,并通过耻垢分枝杆菌作为检定菌对筛选到的样品进行抗菌活性测定及细胞毒性评价。【结果】运用此模型筛选了化合物样品11 600个,发酵液样品5 200个,筛选得到阳性化合物9个,阳性发酵液37个。而后通过耻垢分枝杆菌作为检定菌的抗菌活性测定及细胞毒性评价后,得到了6个发酵液阳性样品。【结论】建立的PheRS抑制剂模型可成功用于化合物和微生物发酵液的高效筛选,得到的6个发酵液阳性样品在酶水平和抗分枝杆菌方面均具有良好活性且毒性较低,值得进一步研究。