酶转化淀粉在国内大纸厂的文化纸纸机表面施胶中应用

文化用纸（包装纸）通过使Biochem L-500淀粉酶转化玉米原淀粉，降低淀粉糊液的粘度，并除去了淀粉-碘混合物的蓝色。减少设备腐蚀，提高成纸质量。     

Antimicrobial lysozyme-containing starch microgel to target and inhibit amylase-producing microorganisms

The aim of this study is to determine the release of lysozyme from oxidized starch microgels and subsequently test its antimicrobial activity. The gels are made of oxidized potato starch polymers, which are chemically cross-linked by sodium trimetaphosphate (STMP). The microgel is negatively charged and interacts with positively charged lysozyme by electrostatic attraction. Application of the lysozyme-containing starch particles to environments contaminated with microbes, may lead to hydrolysis of the starch by microbial enzymes. As a result, lysozyme is released in the environment where it inhibits microbial growth. In this study, first bacteria were screened for amylase production and lysozyme sensitivity. Then, the bacteria were mixed with empty gel particles (i.e., without lysozyme) in a Nutrient Broth liquid medium to test whether the bacteria that can produce amylase are also able to degrade oxidized starch gel. Subsequently the amylase-producing lysozyme sensitive bacteria, Bacillus licheniformis 7558 and Bacillus subtilis 168, were selected for further quantification of the antimicrobial activity of the gel-lysozyme particles after incubation with these bacteria in Nutrient Broth liquid suspensions. The results prove that the starch microgel has a potential as antimicrobial carrier targeting amylase-producing and lysozyme-sensitive bacteria. The controlled antimicrobial delivery for inactivating undesired microorganisms may find applications in food related systems, where amylase-producing bacteria may be abundantly present.     

Stabilization of α‐amylase by chemical modification with carboxymethylcellulose

Carboxymethylcellulose activated by periodate oxidation was covalently linked to porcine pancreatic α‐amylase (EC 3.2.1.1). The specific activity of the conjugate prepared was 54% of the native enzyme. The carbohydrate content was estimated to be 62% by weight as a result of the modification of 67% of the amino groups from the protein. In comparison with the native enzyme, the thermostability and pH stability were improved for α‐amylase by this modification. The conjugate was also more resistant to the action of denaturant agents such as urea and sodium dodecylsulfate. We conclude that modification of enzymes by the anionic polysaccharide carboxymethylcellulose might be a useful method for improving enzyme stability under various denaturing conditions. © 1999 Society of Chemical Industry     

OCC制浆过程中抑制二次淀粉降解的研究

研究了4种金属离子(Cu²⁺、Zn²⁺、Mn²⁺、Li+)对二次淀粉降解的抑制效果及其最佳添加量,并利用杀菌剂与其协同处理,探究OCC制浆过程中二次淀粉降解的抑制问题。结果表明,Cu²⁺具有最佳的抑制效果。当反应时间4 h、Cu²⁺添加量为0.20 mol/t时,原淀粉几乎不降解;当反应时间4 h、Cu²⁺添加量为0.024 mol/t时,酶解淀粉的降解率最低,为15.4%;当杀菌剂与Cu²⁺协同作用时,相比单独添加杀菌剂,原淀粉4 h抑制效果提升58.0%,酶解淀粉4 h抑制效果提升31.2%。     

中温淀粉酶改性玉米淀粉在纸板中的应用研究

目的 以酶改性玉米淀粉为施胶剂,对箱纸板和瓦楞纸板进行表面施胶,研究其对纸板物理性能的影响.方法 使用中温淀粉酶改性玉米淀粉,测试其粘度变化;然后将酶改性淀粉施胶于箱纸板和瓦楞纸板表面,测试箱纸板的挺度、环压强度、耐破度、耐折度、抗张强度以及瓦楞纸板的边压强度和耐破度,探索酶改性玉米淀粉对箱纸板和瓦楞纸板表面施胶的最佳用量.结果 使用2.5μL淀粉酶改性质量分数为10％的玉米淀粉后,将其施胶于箱纸板表面,此时箱纸板的物理性能最优.与空白样相比,箱纸板的横向挺度提高了380％,纵向挺度提高了464％,环压强度提高了53.2％,纵向抗张强度提高了10.6％,横向抗张强度提高了9.6％,箱纸板的耐破度变化不大,耐折度降低;经2μL淀粉酶改性质量分数为10％的玉米淀粉后,将其施胶于瓦楞纸板表面,其边压强度提升最多;与空白样相比,边压强度提高了45.5％.结论 酶改性玉米淀粉的制作工艺简单,为制备高性能纸板提供了参考依据.     

Proteinaceous Inhibitors of Trypsin and of Amylases in Developing and Germinating Seeds of Pigeon Pea ( Cajanus cajan(L) Millsp)

Inhibitors of trypsin and amylase in the extracts of developing seeds of 12 pigeon pea cultivars were analysed using a gel-X-ray film contact print technique and an enzyme-inhibitor assay, respectively. The inhibitors of amylase and trypsin in the extracts of germinating seeds of a pigeon pea cultivar (BDN2) were also studied. Nine trypsin inhibitor bands were detected in mature seeds of all the 12 cultivars. Inhibitory activities against amylase and trypsin were not detected in the extracts of seeds collected 11 and 27 days after flowering (DAF) by the enzyme-inhibitor assay. However, up to three trypsin inhibitor bands could be detected in the extracts of seeds collected 27 DAF by the gel-X-ray film contact technique. Two new slow-moving trypsin inhibitor bands were detected in the extracts of germinating seeds of BDN2 cultivar. These bands were prominent in extracts of seeds 10 days after germination (DAG). The amylase inhibitors and trypsin inhibitors in pigeon pea seeds are late synthesised proteins, their highest levels were observed in mature seeds and they were found to be slowly degraded during germination. Significant inhibitor activities were observed even 15 DAG. The amylases in developing seeds are insensitive to endogenous inhibitors.     

固态发酵生产细菌α-淀粉酶

采用国内α 淀粉酶生产常用菌株BF7658变异菌种 ,直接以麸皮为原料固态发酵法生产α 淀粉酶 ,得到较适宜的条件为 :培养基初始含水量 (质量分数 )为 60 % ,起始 pH自然 ,液体接种量为 5mL/kg ,3 7～ 3 9℃培养 4 8～ 60h ,三角瓶培养产酶水平可达 1 2 4 8U/ g ,浅盘培养平均产酶可达 1754U/ g .固态发酵生产细菌α 淀粉酶产酶水平为液体深层发酵法的 4～ 5倍 ,并且成本低廉 ,具有较好的经济和环境效益 .     

枯草芽孢杆菌变异菌株的α-淀粉酶分离纯化及酶学性质的研究

从枯草芽胞杆菌变异菌株培养得到的α—淀粉酶,通过硫酸铵沉淀,DEAE-葡聚糖凝胶A-50,葡聚糖凝胶G-100以及超滤浓缩等操作,获得该酶的纯样品,该酶的分子量、等电点分别为52.5KD、pI 4.6。该酶的最适pH和温度分别为pH6.0及65℃,稳定pH范围为pH4.5～7.5,而且在50℃时该酶活力较稳定。Ca~(2 )、Mg~(2 )、Li~ 对酶活有激活作用,而Ag 、Al~(3 )、Cu~(2 )、Fe~(2 )、Zn~(2 )、Mn~(2 )、Ni~(2 )和CO~ 对酶活有抑制作用。另外,该酶对可溶性淀粉的分解限度为42.8％,由此可估计该酶属于糖化型α—淀粉酶。     

酿酒行业中支链淀粉快速检测方法的研究和应用

为了缩短检测白酒酿造的主原料高粱中支链淀粉含量的时间,减小操作过程中的人为误差。研究建立了快速检测淀粉和直连淀粉含量,通过计算得到支链淀粉含量的方法,对方法的检测效果进行了评价,并与国标方法进行比对,结果表明两者没有显著性差异。     

Amylolytic Cultures of Lactobacillus acidophilus : Potential Probiotics to Improve Dietary Starch Utilization

ABSTRACT: The amylase activity of twenty strains of Lactobacillus species isolated from intestinal contents of pigs was studied in vitro. Hydrolysis of starch was measured by following the disappearance of starch in a broth medium during the growth of all three strains. The amount of enzyme activity varied among strains. Three strains (A-4, L9 and L23) were selected for further study based on their high amylolytic activity in a broth containing soluble starch as the only carbohydrate source. Strains A-4 and L23 were identified as L. acidophilus and strain L9 was identified as L. fermentum. Among the three cultures, L. acidophilus L23 was selected as a potential candidate for use as a probiotic for improving digestion of starch in pigs based on its growth and hydrolysis of raw starch. The enzyme activity of L. acidophilus L23 was associated with the cell envelope and that of L. fermentum L9 was extracellular. The enzyme activity of L. acidophilus A4 was found in both locations. The enzyme activity of L. acidophilus L23 was inducible rather than constitutive.