纳豆激酶固态发酵的参数优化

方法:在对实验室分离的纳豆激酶产生菌进行菌株鉴定及其酶学性质研究的基础上,对影响菌株固态发酵产酶的工艺参数进行了优化研究.结果:发酵温度、发酵时间及培养基碳氮比、料水比、pH对纳豆激酶的产生都有较大影响,而接种量对纳豆激酶影响较小;在优化条件下,纳豆激酶固态发酵酶活可达到8 300U/g,为已知最高纳豆激酶单位酶活.     

响应面法优化酶法水解大豆异黄酮糖苷

采用 Design-Expert 软件中 Central Composite Design（CCD）响应面分析方法对β-葡萄糖苷酶水解大豆异黄酮糖苷的4个主要因素（水解温度、水解时间、pH 以及加酶量）进行优化。方差分析发现,影响大豆异黄酮糖苷水解最主要的因素有温度、水解时间和 pH。对各因素进行回归拟合,得到最佳实验条件分别为：温度46．2℃,反应时间94 min,pH 5．1,酶量61单位,此时大豆异黄酮苷元含量达到0．096 g·L－1,比优化前提高了22％。     

腐植酸生产菌株——链霉菌发酵条件研究

利用链霉菌ST菌株发酵生产腐植酸。在蔗渣发酵培养基的基础上,采用一次回归正交试验,对腐植酸发酵过程中接种量（I）、通气量（搅拌次数,A）、温度（T）及时间（D）4个因素对腐植酸产量的影响情况进行分析。结果表明发酵时间的影响最为显著,接种量影响显著;所得到的回归方程有效且可信度高,回归方程为Y=6．0356＋0．02501＋0．0033A＋0．0069T＋0．2425D,其中各因素均与腐植酸产量呈正相关性。该回归方程为腐植酸生产过程链霉菌ST菌株发酵条件的控制提供了很好的指导作用。     

米糠蛋白抗氧化活性肽的制备

以水解度(DH％)和对DPPH自由基清除率为指标,筛选出制备米糠蛋白抗氧化活性肽的最适蛋白酶.研究最适蛋白酶的酶解条件,探讨底物浓度、蛋白酶的加入量、pH值、酶解时间等因素对水解度(DH％)和DPPH自由基清除率的影响;在单因素基础上采用Box-Behnken响应曲面中心组合设计法,对酶解米糠蛋白的工艺进行优化.试验结果表明,在加酶量13970.82 U/g,时间3.05h,底物浓度4.97％的水解条件下,米糠蛋白的水解度能够达到23.67％,活性肽对DPPH自由基清除率达到64.26％.     

响应曲面法制备蛹虫草子实体酶解液的研究

为了将蛹虫草开发成为便于人们食用的产品形式,本实验以不同的酶对蛹虫草进行水解得到蛹虫草酶解液.以水解度和酶解液中腺苷含量为目标,确定选用木瓜蛋白酶.以水解度为响应指标,应用响应曲面法对蛹虫草酶解条件进行优化,根据Box-Behnken中心组合实验设计原理,选取酶解温度、酶解时间、加酶量三因素三水平进行中心组合实验,响应曲面分析结果表明水解最佳条件为:酶解温度60.92℃,酶解时间11.85 h,加酶量1.02％,此条件下蛹虫草的水解度达到最大.水解度验证值61.27％与预测值60.76％接近,说明建立模型正确.     

根霉12号固体发酵产生纤溶酶工艺条件的研究

研究了根霉12号固体发酵产生纤溶酶的工艺条件。采用单因素试验、均匀设计方法对固体发酵培养基的碳源、氮源、碳氮比、初始pH、加水量、无机盐加量进行了优化;采用正交试验对发酵时间、接种量进行了研究。结果表明,实验范围内根霉12固体发酵产纤溶酶的适宜培养基组成为：麸皮：豆粕=1:2,初始pH5.0,加水量0.75ml／g物料,MnSO4-H2O 和 (NH4)2SO4加量分别为0.25％和1.42％(对物料)。适宜培养条件为接种量10^7个孢子/g 物料,培养时间 72h。优化条件下的纤溶酶产量平均达 791.81u／g物料。     

木薯生料发酵生产燃料乙醇的工艺优化

为了实现生料发酵更好的应用,考察料水比、发酵温度、氮源及接种量等因素对木薯生料发酵生产燃料乙醇的影响,并通过正交试验分析主要因素之间的相互作用。结果表明:木薯生料发酵产燃料乙醇的最佳条件为料水比1∶2.0,活性干酵母接种量0.15%(质量分数),发酵温度32℃,发酵周期120 h,尿素添加量0.20%(质量分数)。在最佳条件下,发酵得到的燃料乙醇的酒精度可达到15.12%(体积分数)。本实验为高效利用木薯生料发酵生产燃料乙醇的工业化生产提供了重要参数。     

双酶法制备螺旋藻多肽的工艺研究

选用碱性蛋白酶和木瓜蛋白酶结合的双酶法对螺旋藻蛋白进行水解。其中,对木瓜蛋白酶水解螺旋藻蛋白的工艺进行优化。以水解度为指标,研究了酶解时间、酶与底物比、pH和酶解温度4种因素对酶解反应的影响。在此基础上设计了3因素(加酶量、酶解温度和pH)3水平的响应面试验。结果表明碱性蛋白酶水解螺旋藻蛋白的最佳酶解条件为:加酶量4300 U/g,pH 7.0,酶解温度55℃,酶解时间160 min;木瓜蛋白酶的最佳酶解条件为:酶底比为4.5%,酶解温度60℃,pH 6.5,酶解时间210 min。利用碱性蛋白酶和木瓜蛋白酶结合的双酶法制得的多肽水解度可达32.90%,与单酶法相比,水解度明显提高。     

苹果渣发酵生产饲料蛋白的工艺条件

采用经试验所筛选出的菌种组合,通过试验,获得了苹果渣发酵的适宜工艺条件：接种比例为１：５－１：１０,接种量１５－３０％,料水比１０：７－１０：８,ｐＨ值为６－７,发酵时间３－４ｄ,静止发酵料层厚度不超过３０ｍｍ。发酵产物测定结果显示,粗蛋白含量达到２９．３０％,提高到４５．７７％。蛋白质含量达到２７．５６％,提高了８２．８８％,粗纤维含量降低了２３．２７％。     

降解豆粕菌株的筛选及其发酵工艺研究

以脱脂豆粕粉为原料,接入产蛋白酶能力较强的菌株进行发酵,通过菌株所产蛋白酶作用于豆粕粉中的大豆蛋白将其水解为大豆多肽。以蛋白酶活力及水解度为指标逐步筛选降解豆粕的菌株,获得菌株CHD16;以水解度作为指标,对菌株CHD16发酵降解豆粕的条件进行了优化。通过液体发酵探讨菌株CHD16适宜的培养基组成、接种时间、接种量与发酵时间。结果表明：在豆粕含量11%,蔗糖含量2%的液体发酵培养基中接种3%的菌龄为21h的液体种子,于温度40℃、转速120r/min条件下发酵48h,豆粕蛋白的水解度可达58%,比条件优化前的水解度提高了88%。     

棘孢曲霉固态发酵柚皮产柚苷酶的条件优化

【目的】以柚皮为原料,优化棘孢曲霉利用柑橘加工副产物固态发酵柚苷酶的条件。【方法】采用高效液相色谱法检测酶活力,通过单因素试验考察固水比、装样量、接种量、温度对柚苷酶发酵的影响,用正交试验优化发酵条件。【结果】单因素试验结果的显著性分析表明培养基的固水比、装样量和培养温度对柚苷酶产量有显著性影响,而接种量影响不显著;经正交试验确定的优化条件是：固水比1:1 (质量体积比),装样量5 g/250 mL三角瓶,温度为30 °C,接种1 mL孢子悬浮液,发酵8 d。在此优化条件下,柚苷酶酶活力为8.19 IU/g干物质,比初始培养基产柚苷酶活力提高7.38倍。【结论】通过对固水比、装样量和发酵温度进行优化,大幅度提高了棘孢曲霉固态发酵柑橘加工副产物的柚苷酶产量,为柚苷酶的生产提供了一种高产发酵工艺。     

Computerized study of interactions among factors and their optimization through response surface methodology for the production of tannin acyl hydrolase by Aspergillus niger PKL 104 under solid state fermentation

Optimization of five parameters (initial moisture, initial pH, incubation temperature, inoculum ratio and fermentation period), as per central composite rotable design falling under the response surface methodology, was attempted in a total of 32 experimental sets, after fitting the experimental data to the polynomial model of a suitable degree, for tannin acyl hydrolase production by Aspergillus niger PKL 104 in solid state fermentation system. The quantitative relation between the enzyme production and different levels of these factors was exploited to work out optimized levels of these parameters by flexible polyhedron search method and confirmed by further experimentations. The best set required 5% inoculum, 6.5 initial pH, 28 °C fermentation temperature, 62% initial moisture and 3 days fermentation time. The optima were worked out under the additional constraints for temperature ( 30 °C) and fermentation time (not more than 3 days) which are essential from industrial conditions and to pre-empt contamination, respectively. The best set resulted in 1.34 times more enzyme production than that was obtained before this optimization. Three dimensional plots, relating the enzyme production to paired factors (when other three factors were kept at their optimal levels) best described the behaviour of solid state fermentation system and the interactions between factors under optimized conditions. The model showed that the enzyme production was affected by all the five factors studied. The initial pH exhibited a positive interaction with moisture but no interaction with other factors. Initial moisture level and inoculum ratio showed negative interaction in contrast to positive interaction between inoculum ratio and fermentation period. It is thus apparent that the response surface methodology not only gives valuable information on interactions between the factors but also leads to identification of feasible optimum values of the studied factors, in addition to 99% (or more) savings on resources as compared to a full factorial traditional optimization method. Response surface methods have not been used earlier for optimizing parameters in solid state fermentation system.The authors thank Dr. S. R. Bhowmik, Director, CFTRI for the interest shown in the work. P. K. Lekha is thankful to the Council of Scientific and Industrial Research, New Delhi, India, for the award of a research fellowship.     

响应面分析法优化大豆肽发酵培养基

采用响应面分析法对大豆肽发酵培养基进行优化,首先采用二水平Plackett-Burman设计对影响大豆肽发酵的8个因素进行筛选,获得影响最大的3个因素为料水比、MgSO_4、糖蜜.再利用响应面分析法对这3个因素进行优化,确定最佳培养基条件为料水比为1∶1.149、MgSO_4浓度为0.048%、糖蜜浓度为0.294%,在此条件下,优化后的大豆肽含量为21.74%,试验值与模型预测值只有1.21%的误差.     

Optimization of whole cell-catalyzed methanolysis of soybean oil for biodiesel production using response surface methodology

Utilizing whole cell biocatalyst instead of free or immobilized enzyme is a potential way to reduce the cost of catalyst in lipase-catalyzed biodiesel production. Rhizopus oryzae (R. oryzae) IFO4697 whole cell immobilized within biomass support particles (BSPs) was used for the methanolysis of soybean oil for biodiesel production in this paper. tert-Butanol was demonstrated to be an ideal reaction medium, in which the negative effects caused by substrate methanol could be eliminated effectively. A central composite design was adopted to study the effect of tert-butanol quantity, methanol quantity, water content and dry biomass of the immobilized cell on biodiesel (methyl ester) yield. Each factor was studied in five levels. Using response surface methodology, a quadratic polynomial equation was obtained for methyl ester yield by multiple regression analysis. Biodiesel yield of 72% could be obtained under the optimal conditions and further verification experiments confirmed the validity of the predicted model.     

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。     

泥炭固体发酵生产单细胞蛋白研究

对以泥炭为唯一碳源,固体发酵生产单细胞蛋白(SCP)进行了一系列的研究。选用酵母菌和黑曲霉进行混合发酵培养,考察影响单细胞蛋白生产的各个因素,如菌种接种量,培养基含水量,发酵时间,发酵温度,培养基外加氮源等。通过正交实验设计确定了优化的培养条件。即:菌种接种量为10%,培养基含水量为300%,28℃培养72 h,以蛋白胨为氮源。     

混菌发酵改良棉粕蛋白工艺及协同作用研究

利用筛选到的Aspergillus niger P1和Bacillus subtilis H1混菌发酵改良棉粕蛋白,以提高其利用率。结果表明,混菌发酵的最佳发酵条件为:棉粕 40 g,硫酸铵0.2%,麸皮15%,含水量50%,接种量 15%,同时接菌且两菌接菌比例(A.niger P1 ∶ B.subtilis H1)为2 ∶ 1,发酵温度30 ℃,pH约为6.0,发酵时间 60 h。在此条件下发酵后棉粕小肽含量可提高至18.36%,平均肽链长度可降至4.23,体外消化率可提高至88.59%,显著提高了改良棉粕蛋白的效果。在相同发酵条件下比较单、混菌发酵过程的各营养指标发现:A.niger P1可分泌丰富的酸性蛋白酶,B.subtilis H1可分泌丰富的中、碱性蛋白酶,混菌发酵各种蛋白酶的活性显著提高。混菌发酵将大多数大于10个氨基酸组成的多肽降解为1~3个氨基酸组成的小肽,降解效果明显优于单菌发酵。两菌株具有很好的"协同性",可充分利用棉粕基质,协同改良棉粕蛋白。     

Fermentative production of chiral acetoin by wild-type Bacillus strains

Abstract

In recent years, there have been many studies on producing acetoin by microbial fermentation, while only a few studies have focused on chiral acetoin biosynthesis. The weight assignment method was first applied to balance the chiral purity (expressed as the enantiomeric excess value) and the titer of acetoin. Bacillus sp. H-18W, a thermophile, was selected from seven Bacillus strains for chiral acetoin production. To lower the cost of the fermentation medium, soybean meal was used as a feedstock. Four kinds of frequently used commercial proteinases with different active sites were tested for the hydrolyzation of the soybean meal, and the combination of the acidic proteinase and the neutral proteinase showed the best results. In a fermentation medium containing 100?g L^?1 glucose and 200?g L^?1 hydrolysate, Bacillus sp. H-18W produced 21.84?g L^?1 acetoin with an ee value of 96.25% at 60?h. This is the first report of using a thermophilic strain to produce chiral acetoin by microbial fermentation. Thermophilic fermentation can reduce the risk of bacterial contamination and can save cooling water. Using soybean meal hydrolysate and glucose as feedstocks, this work provides an economical and alternative method for the production of chiral pure acetoin.     

耐底物腈水合酶融合子的产酶条件优化

采用正交设计法对耐底物腈水合酶融合子的发酵条件进行优化,以发酵液起始pH,发酵周期,接种量,装料系数作为考察因素,最终确定最佳发酵条件为:起始pH8.0、发酵周期54h、接种量12％、装液系数12％.在此优化条件下融合子腈水合酶的活力达到1100万U/ml,较优化前提高了83.3％.通过响应面法对发酵培养基配方进行优化研究,采用Plackett-Burman法对8个因素进行了筛选,结果表明,葡萄糖、尿素、磷酸氢二钾、磷酸二氢钾是影响发酵液腈水合酶产量的主效应因子.用最陡爬坡试验及Central composite design设计进一步优化,利用Design-Expert软件进行二次回归分析,得到各因素的最佳浓度为:葡萄糖22.62g/L、尿素9.76g/L、K2HP04 1.22g/L、KH2PO41.268g/L.在此培养基优化配方下融合子腈水合酶的活力达到1280万U/ml,较原配方的酶活提高了16.4％.     

一株产碱性蛋白酶芽孢杆菌的筛选、鉴定及应用初探

为了筛选碱性蛋白酶产生菌并探讨其对蛋白质饲料的发酵效果,以肉粉厂表层土壤为菌株分离源,利用脱脂牛奶培养基分离和纯化蛋白酶产生菌,通过形态特征、生理生化和16S rRNA基因序列分析确定菌株的分类地位,并采用L9(33)正交设计研究筛选出的优势菌种的接种量(3％、6％和12％)、种子液培养时间(12 h、24h和48 h...