葡萄籽多酚类物质的盐析萃取

采用乙醇/(NH4)2SO4两相盐析体系,从酿酒副产物葡萄籽中提取多酚、类黄酮和原花青素。实验结果表明,在室温下用组成(质量分数)为30%乙醇/18%(NH4)2SO4的体系提取葡萄籽中多酚、类黄酮以及原花青素,得率分别为64.54、42.45、23.16 mg·g-1;它们富集于上相乙醇相,萃取回收率分别为97.31%、98.19%、97.92%。室温条件下用2,2-二苯基-1-苦基肼(DPPH)法与2,2′-连氮基-双-(3-乙基苯并二氢噻唑啉-6-磺酸)(ABTS)法测定两相盐析萃取物抗氧化、清除自由基能力,IC50分别为61.85、71.76 mg·L-1,比传统的热回流提取物具有更强的抗氧化活性。     

盐析萃取菊芋发酵液中的2,3-丁二醇(英文)

The removal of solid impurities and separation of target products from a fermentation broth is becoming more tedious with the utilization of lignocelluloses as source of substrate.2,3-Butanediol,an important chemical used widely is also a main product of sugar-based fermentation carried out by Klebsiella pneumoniae.In this study,we investigated the use of salting-out extraction(SOE) that employed a K2HPO4/ethanol system consisting of 21% ethanol and 17% K2HPO4(mass fraction) to separate 2,3-butanediol from the viscous Jerusalem artichoke-based fermentation broth.After SOE,about 98% of solid matters was removed,and the viscosity decreased from 72.5 mPa s in the original fermentation broth to 4.4 mPa s in the top phase.The partition coefficient and yield of 2,3-butanediol reached 13.4 and 99%,respectively,and 89% of soluble proteins was removed from the broth.The results showed that SOE is an efficient way for isolating 2,3-BD from a highly viscous fermentation broth by removing much of the solid matters within the broth.     

甘油连续生物歧化过程的过渡行为及其数学模拟

用肺炎杆菌将甘油转化为１,３－丙二醇过程对稀释速率和底物进料浓度变化的过渡行为反映了细胞生长和胞内物质代谢在不同条件下存在着显著的差异。体系的过渡响应取决于操作条件变化前后系统所处的状态,当底物浓度由限制状态向剩余状态过渡时,甘油的残余浓度不断上升,而乙醇的浓度则逐渐下降,同时生物量、１,３－丙二醇和乙酸的浓度呈现先增后降的趋势。本文用“甘油浓度变化速率”的概念修正了菌体生长模型,并对甘油歧化过程     

生物转化法生产2,3-丁二醇的研究

介绍国内外关于生物转化法生产2,3-丁二醇的研究情况,其中包括转化过程中菌种的选择及其改造、发酵底物的选择、发酵条件及产量、产物的分离提纯方法等。并对该生物转化过程提出一些新的改进方法,以期降低生产成本,解决日益严重的能源危机和环境污染等问题。     

Improved Ethanol Production from Xylose by Candida shehatae Induced by Dielectric Barrier Discharge Air Plasma

Xylose fermentation is essential for ethanol production from lignocellulosic biomass. Exposure of the xylose-fermenting yeast Candida shehatae （C. shehatae） CICC1766 to atmospheric pressure dielectric barrier discharge （DBD） air plasma yields a clone （designated as C81015） with stability, which exhibits a higher ethanol fermentation rate from xylose, giving a maximal enhancement in ethanol production of 36.2% compared to the control （untreated）. However, the biomass production of C81015 is lower than that of the control. Analysis of the NADH （nicotinamide adenine dinucleotide）- and NADPH （nicotinamide adenine dinucleotide phosphate）- linked xylose reductases and NAD＋-linked xylitol dehydrogenase indicates that their activities are enhanced by 34.1%, 61.5% and 66.3%, respectively, suggesting that the activities of these three enzymes are responsible for improving ethanol fermentation in C81015 with xylose as a substrate. The results of this study show that DBD air plasma could serve as a novel and effective means of generating microbial strains that can better use xylose for ethanol fermentation.     

脂肪酶蛋白质工程研究进展

脂肪酶在油脂化学、食品工业、有机合成和生物柴油等多个领域有着广泛应用。利用蛋白质工程在分子水平上修饰脂肪酶,可以提高酶活、稳定性和其它催化性质。该文综述了蛋白质工程的基本概念和利用不同方法开发新突变脂肪酶的应用。     

固定化磷脂酶A催化制备DHA型磷脂

以磷脂酰胆碱(PC)富集物和二十二碳六烯酸(DHA)浓缩液为底物,正己烷为反应介质,在固定化磷脂酶A1(PLA1)的催化作用下,制备DHA型磷脂(PL-DHA)。研究了底物摩尔比、加酶量、溶剂用量、反应温度、水活度、反应时间对PL-DHA制备的影响。通过条件优化,确定最佳条件为:DHA浓缩液和PC的摩尔比为4∶1,加酶量为2种底物总质量的20%,溶剂用量为4 m L,反应温度为40℃,反应时间为2 h。经气相色谱定量分析,得到的磷脂中DHA的含量为17.7 mg/g PL,并用棒状薄层色谱火焰离子检测器(TLC-FID)分析了PC含量随反应的变化。     

可食性活性涂膜在鲜切果蔬保鲜中的应用

可食性涂膜是一种由天然可食性材料制成的选择透过性薄膜,具有调节果蔬内部气体交换、减少水分损失、降低腐烂率及延长货架期的特性,在果蔬包装及保鲜领域中已引起广泛关注。鲜切果蔬具有新鲜、方便、快捷等特点,已在全球范围内广泛供应餐饮业及零售业。可食性涂膜作为多种食品添加剂的载体常应用于生鲜产品中,且将活性添加剂与可食性涂膜结合可以延长鲜切果蔬的货架期,提高果蔬品质,减少果蔬表面致腐及致病菌增长的风险。可食性活性涂膜将作为一种绿色、安全、营养的保鲜技术,并将应用于鲜切果蔬保鲜领域的研究。本文综述了可食性涂膜的分类及其添加的抗菌剂、抗氧化剂、塑形剂、营养素等活性成分在鲜切果蔬保鲜中的应用,旨在开发用于鲜切果蔬保鲜的功能性可食性涂膜。     

纳米技术在药物制剂中的应用

综合报道了纳米技术在药物制剂中的应用，包括：制备材料与方法，给药途径与体内分布，吸收；药物从微粒和纳粒中的释放；微粒和纳粒系统在药物制剂中的应用。     

大气压冷等离子体诱变产1,3-丙二醇菌株Klebsiella pneumoniae

采用大气压冷等离子体介质阻挡放电法对产1,3-丙二醇的克雷伯氏菌进行诱变,采用诱变与筛选同时进行的单细胞平板诱变方法,同时获得了可耐受高浓度甘油且1,3-丙二醇产量较高的优良突变株. 对诱变后菌的间歇发酵结果表明,诱变菌株比出发菌株1,3-丙二醇的质量转化率提高了23%,对数期比生长速率提高了18%. 批式流加发酵过程中,1,3-PD浓度在发酵36 h时达到70.5 g/L,甘油的质量转化率为0.57 g/g,分别比野生菌提高47%和58%. 该诱变和筛选方法具有操作简单、效率高等特点,对具有工业应用价值的菌株筛选具有实用价值.