L-赖氨酸产生菌FH128菌株的研究(Ⅰ)FH128菌株的选育及摇瓶发酵

以赖氨酸产生菌Ａ１１１（ＨＳ－、ＡＥＣｒ）为出发株,经化学诱变剂ＭＮＮＧ（Ｎ－甲基－Ｎ′－硝基－Ｎ－亚硝基胍）及单氟醋酸处理获得单氟醋酸抗性突变株Ｆ７９,摇瓶发酵产Ｌ－赖氨酸盐酸盐７．０％～７．５％,对糖转化率３８％～４０％,分别比Ａ１１１株提高约２５％及２０％。然后,再以Ｆ７９菌为亲株经ＭＮＮＧ及噻唑丙氨酸处理获得噻唑丙氨酸抗性突变株ＦＨ１２８,在适宜的培养条件下,摇瓶发酵产Ｌ－赖氨酸盐酸盐８．５％～９．５％,最高产酸率１１％,对糖转化率４５％～５０％。在１６Ｌ自控发酵罐发酵,产Ｌ－赖氨酸盐酸盐１２％～１４％,对糖转化率４０％～４５％;在２０～１００ｍ３发酵罐发酵,产酸率为８．５％～９．５％,对糖转化率４０％～４２％,提取总收率８０％～８５％,成品（饲料级Ｌ－赖氨酸盐酸盐）质量符合国家标准（ＧＢ８２４５－８７）。ＦＨ１２８菌株遗传性能稳定,营养要求粗放,工艺较简单,便于工业化,二年前已应用于工业生产。     

基因工程菌发酵合成L－苏氨酸－N~（15）

采用含有稳定同位素１５Ｎ－硫酸铵为主要氮源的专用发酵培养基配方和提取精制条件,在国内、外首次采用基因工程菌ＡＡ７（ｐＴＨ２）（ＡＨＶｒＡＥＣｒ,Ｔｈｒ－Ｎ－,Ｈｏｍｒ,Ａｐｒ）直接发酵方法研制Ｌ－苏氨酸－Ｎ１５高丰度精制产品。每ｍｏｌ１５Ｎ－硫酸铵实际得到０．６３８ｍｏｌＬ－苏氨酸－Ｎ１５,产品Ｎ１５丰度达９９．０９％,仅比原料１５Ｎ－硫酸铵丰度下降０．４２％,提取精制得率高达９２．８３％。     

L—赖氨酸产生菌FH128菌株的研究：（Ⅰ）FH菌株的选育及摇瓶发酵

以赖氨酸产生菌Ａ１１１（ＨＳ＾－,ＡＥＣ＾ｒ）为出发株,经化学诱变剂ＭＮＮＧ（Ｎ－’－硝基－Ｎ－亚硝基胍）及单氟醋酸处理获得单氟生突变株Ｆ７９,摇瓶发酵产Ｌ－赖氨酸盐酸盐７．０％－７．５％,对糖转化率３８％－４０％,分别比Ａ１１１株提高红２５％及２０％。     

神经生长因子在6－OHDA化学性去交感神经中的保护作用

本实验用６－ＯＨＤＡ造成成年小白鼠领下腺化学性去交感神经,观察了神经生长因子对该神经的保护作用。６－ＯＨＤＡ（１５ｍｇ／ｋｇｉｐ）处理后２４ｈ腺体内去甲肾上腺素（ＮＥ）含量降至正常水平的２％以下。若在６－ＯＨＤＡ处理同时开始多次给予神经生长因子（ＮＧＦ）,则ＮＥ残留量明显提高。减小６－ＯＨＤＡ剂量至１０ｍｇ／ｋｇ,ＮＥ残留量增加,同时ＮＧＦ的作用亦较用６－ＯＨＤＡ１５ｍｇ／ｋｇ时更为显著。若提前２４ｈ给予ＮＧＦ,尽管仍显著提高ＮＥ残留量,但程度却显然低于与６－ＯＨＤＡ同时给予者。以上结果表明外源性ＮＧＦ对６－ＯＨＤＡ造成交感神经化学性损毁有保护作用,此作用与神经受损的严重程度以及ＮＧＦ处理时间有关。     

L—山梨糖脱氢酶的纯化及性质的研究

从５Ｌ罐发酵Ｌ－山梨糖的Ｇｌｕｃｏｎｉｂａｃｔｅｒ ｏｘｙｄａｎｓ ＳＣＢ３２９和Ｂａｃｉｌｌｕｓ ｔｈｕｒｉｎｇｉｅｎｓｉｓ ＳＣＢ９３３混合菌株中差速离心收集ＳＣＢ３２９菌体,破碎,离心获得无细胞抽提液,硫酸铵分级沉淀蛋白后依次经ＤＥＡＥ Ｃｅｌｌｕｌｏｓｅ ５２和Ｑ Ｓｅｐｈａｒｏｓｅ ＦＦ柱层析分得到了Ｌ－册梨糖脱氢酶（ＳＤＨ）,它能将Ｌ－册梨糖脱氢氧化为Ｌ－册梨酮,ＳＤＳ－ＰＡＧＥ电泳测     

蛋白质定点PEG化研究：97Cys－IFH－γ的巯基专—PEG修饰

蛋白质定点ＰＥＧ化研究：９７Ｃｙｓ－ＩＦＨ－γ的巯基专—ＰＥＧ修饰唐微,常远,徐　飞,郑仲承,刘新垣（中国科学院上海生物化学研究所,２０００３１）关键词人干扰素－γ;定点修饰;半胱氨酸目前进行的ＰＥＧ化反应,多是针对蛋白质肽链上自由末端氨基进行的,由...     

N-乙酰-L-半胱氨酸的合成及其在医药上的应用

概述了近几十年来国内外关于Ｎ－乙酰－Ｌ－半胱氨酸的合成方法及其在医药上的应用。     

用原生质体融合技术选育2—酮基—L—古龙酸高产菌株的研究

对革兰氏阳性的地衣芽孢杆菌（Ｂａｃｉｌｌｕｓｌｉｃｈｅｎｉｆｏｒｍｉｓ）Ｈ１９和革兰氏阴性的２－酮基－Ｌ－古龙酸产生菌Ｓ１９的原生质体的制备条件进行了研究,并采用聚乙二醇作诱导剂进行了两菌株的原生质体融合,用链霉素作为抗性标记对融合子进行了选择。从１７株产生２－酮基－Ｌ－古龙酸的融合子中选出了一株连续传代八次产酸高且产量稳定的融合子１５号。融合子１５号具有两个亲本菌株所具有的一些特性。     

微生物发酵合成L－缬氨酸－~（15）N

采用含有稳定同位素￣（１５）Ｎ－硫铵为主要氮源的专用发酵培养液配方和相应的工艺条件,在国内首次用微生物直接发酵研制成Ｌ－缬氨酸－￣（１５）Ｎ高丰度精制产品。产品￣（１５）Ｎ丰度９７．６８％,反比原料￣（１５）Ｎ－硫铵丰度下降０．５３％,Ｌ－缬氨酸－￣（１５）Ｎ产酸率最高达４％以上（未校正）。每克￣（１５）Ｎ－硫铵可得到１克以上的Ｌ－缬氨酸－￣（１５）Ｎ（分析值）。提取精制收率平均为８０－９０％（单程）,最高达到９５％以上（二次提取）。实际每克￣（１５）Ｎ－硫铵可得０．６克左右的Ｌ－缬氨酸－￣（１５）Ｎ精制产品。     

L-SOD发挥活性作用的可能机制

氧化剂、还原剂处理前后,Ｌ－ＳＯＤ的活性及紫外光谱发生变化,Ｈ２Ｏ２使Ｆｅ（Ⅲ）吸收增强,同时钝化Ｌ－ＳＯＤ的活性;加入保险粉后,Ｌ－ＳＯＤ重新活化,Ｆｅ（Ⅲ）吸收减弱．ＮＥＭ封闭Ｃｙｓ后,Ｌ－ＳＯＤ紫外吸收谱发生变化,且活性减弱．说明Ｆｅ辅基及Ｃｙｓ是活性发挥的必需基团．     

牛磺酸对损伤的心肌肌膜ATPase活性影响的研究

本研究以异丙肾上腺素（Ｉｓｏｐｒｏｔｅｒｎｏｌ,Ｉｓｏ．）诱导的大鼠心肌损伤为模型,观察牛磺酸（Ｔａｕｒｉｎｅ,Ｔａｕ）对损伤心肌肌膜上Ｎ＿ａ￣＋—Ｋ＿－￣＋ＡＴＰａｓｅ、Ｃ＿ａ￣（２＋）－ＡＴＰａｓｅ、Ｍ＿ｇ￣（２＋）ＡＴＰＡＳＥ活性的影响。按Ｄａｈａｌｌａ方法分离及鉴定心肌肌膜同时分别测定三种ＡＴＰａｓｅ活性,结果：Ｉｓｏ组,与Ｔａｕ＋Ｉｓｏ组的三种ＡＴＰａｓｅ活性明显低于对照组与Ｔａｕ组,且同时Ｔａｕ＋Ｉｓｏ组明显高于Ｉｓｏ组但对照组与Ｔａｕ组之间差别无显著性。结果提示：牛磺酸能提高异丙肾上腺素诱导心肌损伤的心肌膜ＡＴＰａｓｅ活性,可能通过其保护心肌肌膜的结构及功能而实现的。     

Enhancing bioethanol production from delactosed whey permeate by upstream desalination techniques

Industrial cheese whey processing comprises generally the isolation of proteins and lactose, but the economic use for the residual molasses, the so‐called delactosed whey permeate (DWP), is still to be improved. One possibility to maximize valorization and to minimize waste water treatment is the conversion of the remaining lactose in the DWP to ethanol by the yeast Kluyveromyces marxianus. This fermentation process depends strongly on the total ash content of the DWP, as high salt concentrations inhibit yeast metabolism. Here, three different approaches were tested to lower the DWP salt content: (i) simple dilution; (ii) nanofiltration; and (iii) electrodialysis. Lactose consumption, ethanol production and time‐dependent yields were compared between the three methods. A dilution of DWP to 60% v/v led to fermentation taking less than 80 h and yield above 7% AbV (alcohol by volume). After nanofiltration, 7.5% AbV was produced in about 80 h, and after electrodialysis, 11% AbV was produced in about 52 h. On the one hand the technical treatments (nanofiltration and electrodialysis) led to enhanced productivity in the fermentations, but, on the other hand, elaborate and extensive preprocessing is needed. Overall, ethanol production from DWP could be enhanced by prior partial desalination.     

复合氨基酸电渗析脱盐过程中的动态

本文利用电渗析技术对猪毛水解废液进行脱盐研究以获取很有应用价值的复合氨基酸。重点研究了各种氨基酸在脱盐过程中的变化行为。     

Efficient salt removal in a continuously operated upflow microbial desalination cell with an air cathode

Microbial desalination cells (MDCs) hold great promise for drinking water production because of potential energy savings during the desalination process. In this study, we developed a continuously operated MDC - upflow microbial desalination cell (UMDC) for the purpose of salt removal. During the 4-month operation, the UMDC constantly removed salts and generated bio-electricity. At a hydraulic retention time (HRT) of 4 days (salt solution) and current production of ∼62 mA, the UMDC was able to remove more than 99% of NaCl from the salt solution that had an initial salt concentration of 30 g total dissolved solids (TDS)/L. In addition, the TDS removal rate was 7.50 g TDS L⁻¹ d⁻¹ (salt solution volume) or 5.25 g TDS L⁻¹ d⁻¹ (wastewater volume), and the desalinated water met the drinking water standard, in terms of TDS concentration. A high charge transfer efficiency of 98.6% or 81% was achieved at HRT 1 or 4 d. The UMDC produced a maximum power density of 30.8 W/m³. The phenomena of bipolar electrodialysis and proton transport in the UMDC were discussed. These results demonstrated the potential of the UMDC as either a sole desalination process or a pre-desalination reactor for downstream desalination processes.     

Consequences of adding gum Arabic as a cryoprotectant on motility and viability of frozen stallion semen

A trial was conducted to check effect of adding gum Arabic (GA) instead of egg yolk (EY) as a cryoprotectant for stallion sperm. Two experiments were designed; experiment I tested adding 3 levels of nonheated GA (i.e., 3, 6 and 9 g/100 mL diluents) in HF-20 extender. However, in experiment II the same levels were tested except that GA was heated at 80 °C for 60 min. HF-20 containing 10% of EY was used as control. In experiment I, sperm frozen in HF-20 containing nonheated GA exhibited lower percentages of motile sperm, progressively motile sperm and sperm with intact plasma membranes, vitality rate, and acrosome integrity after cooling or after deep freezing. Frozen semen in HF-20 containing 3–6% of preheated GA in experiment II maintained sperm motility at 46–50% and elevated progressive motility at 27%. The semen diluted in preheated GA (6%) and frozen exhibited a fertility rate of 40% (2/5). A similar fertility rate (40%) was found in the control semen (i.e. 10%) compared to those that were inseminated with frozen semen in preheated 3% GA (20%, 1/5). These results suggest that preheated GA could be used as an alternative cryoprotectant for cryopreserving stallion sperm.     

Recovery of lactic acid from fermentation broth by the two-stage process of nanofiltration and water-splitting electrodialysis

A two-stage process of nanofiltration and water-splitting electrodialysis was investigated for lactic acid recovery from fermentation broth. In this process, sodium lactate is isolated from fermentation broth in the first stage of nanofiltration by using an NTR-729HF membrane, and then is converted to lactic acid in the second stage by water-splitting electrodialysis. To determine the optimal operating conditions for nanofiltration, the effects of pressure, lactate concentration, pH and known added impurities were studied. Lactate rejection was less than 5%, magnesium rejection approximated 45%, and calcium rejection was at 40%. In subsequent water-splitting electrodialysis, both the sodium lactate conversion to lactic acid and sodium hydroxide recovery, were about 95%, with a power requirement of 0.9∼1.0 kWh per kg of lactate.     

Design of a bactericidal hydrogel scaffold containing genipin crosslinked HF-18 peptide

Wound healing is a process getting affected by internal and external factors and might be interrupted by infections. To overcome infections during wound healing, novel antibacterial agents such as antimicrobial peptides have gained popularity because of the rising antibiotic resistance. Therefore, in this study, a three-dimensional polymeric scaffold was designed for the controlled release of HF-18 peptide, with the contribution of hyaluronic acid, chondroitin sulfate, and chitosan polymers with the crosslinker genipin. The obtained scaffold structure (OPT) was found to have interconnected pores, was pH-responsive and swelled more in acidic conditions (5446.5% at pH: 5.0). It was observed that HF-18-loaded OPT (P-OPT) was able to release HF-18 peptide both in acidic and neutral conditions in a controlled release manner. This study also demonstrated that both OPT and P-OPT were biocompatible and promoted L929 cell attachment and migration. Antimicrobial activity assessments demonstrated that P-OPT was effectively bactericidal on Staphylococcus aureus and methicillin-resistant S. aureus. Moreover, OPT produced a synergistic effect on the antimicrobial activity of HF-18 peptide, as P-OPT showed activity below the reported MIC value. As a result, OPT is considered a promising scaffold as a carrier for HF-18 for wound healing.     

Expression of a male-specific factor on various stages of preimplantation bovine embryos

Four-cell to blastocyst stage bovine embryos were collected from superovulated donors and cultured for 90 min in Ham's F-10 medium (HF-10) containing 10% (V/V) absorbed anti-histocompatibility (H)-Y antiserum. Embryos were then washed 3 times and placed in HF-10 supplemented with 10% (V/V) fluorescein isothiocynate (FITC)-conjugated goat anti-mouse gamma globulin. After an additional wash, embryos were placed in fresh drops of HF-10, individually evaluated at 200 X magnification, and classified as either fluorescent (H-Y-positive) or nonfluorescent (H-Y-negative). Embryos were then placed in drops of HF-10 containing 14% vinblastin and cultured for 4-6 h. Embryos were coded and individually karotyped, and the sex chromosomes were identified. H-Y antigen was detected as early as the eight-cell stage, but not at the four-cell stage. Seventy-nine percent of fluorescent embryos and 89% of nonfluorescent embryos were XY and XX, respectively. Another experiment was carried out in which H-Y antigen was detected on intact inner cell masses (ICM) isolated by immunosurgery from expanded blastocysts that also had been assayed for H-Y antigen. Eighty-eight and 92%, respectively, of ICM classified as fluorescent or nonfluorescent had been scored the same as intact blastocysts. It is concluded from these data that H-Y antigen can be detected on eight-cell to blastocyst stage bovine embryos. There appears to be a localization of detectable antigen in the area of the ICM at the expanded blastocyst stage. Detection of H-Y antigen is an effective, noninvasive method for identification of the sex of preimplantation bovine embryos.     

Raw Starch-digestive Glucoamylase Productivity of Protease-less Mutant from Aspergillus awamori var. kawachi

Mutation experiments were performed to decrease the protease productivity of Aspergillus awamori var. kawachi using ultraviolet light and N-methyl-N'-nitro-N-nitrosoguanidine. The selected mutant HF-15 showed reductions in protease productivity of 93%, 84% and 50% in solid wheat bran culture, shaking Medium B and wheat bran cultures, respectively, as compared with the parent. Protease-less mutant HF-15 failed to produce α-mannosidase, and N-acetyl-β-d-glucosaminidase productivity decreased by 35%. Mutant HF-15 specifically produced a high amount of raw starch-adsorbable and raw starch-digestive glucoamylase similar to GA I under all tested cultural conditions. On the contrary, high protease-producing mutant HF-10 produced a glucoamylase with very limited adsorption and digestion capacity on raw corn starch, and lower hydrolysis toward gelatinized potato starch and glycogen that was similar to GA I'.