微生物及酶对己内酰胺的降解动力学研究

采用微生物菌株和从该菌株提取的粗酶液对己内酰胺进行降解，并对己内酰胺的降解动力学进行了研究．结果表明，初始己内酰胺的浓度越小，降解速率常数越大，半寿期越短，微生物的降解能力越强；由微生物提取的粗酶液（胞外酶）的Km值较小，对己内酰胺有较强的亲和力，可有效地降解己内酰胺。     

Degradation of cellulosic and hemicellulosic substrates using a chelator‐mediated Fenton reaction

The involvement of catechol and hydroxamate chelators, along with hydrogen peroxide and Fe³⁺, in the degradation of cellulosic and hemicellulosic substrates was examined with the purpose of improving our current knowledge of the non‐enzymatic mechanisms involved in wood biodegradation by fungi. It could be demonstrated that a catechol chelator‐mediated Fenton reaction not only clearly degraded hemicellulosic substrates but also significantly accelerated and increased the effectiveness of degradation reactions. On the other hand, when a hydroxamate chelator‐mediated Fenton reaction was used, an inhibitory effect was observed. When cellulosic substrates underwent a chelator‐mediated Fenton reaction, no significant difference in degradation was observed between catechol and hydroxamate chelator‐mediated reactions. However, a catechol‐mediated reaction did accelerate the degradation of cellulosic substrates at the beginning of reactions. In addition, it was observed that with a chelator‐mediated Fenton reaction, oxidation of cellulose proceeds depolymerization. Copyright © 2005 Society of Chemical Industry     

Biodegradation of low‐density polyethylene/thermoplastic starch foams before and after electron beam irradiation

Foamy low‐density polyethylene/plasticized starch (LDPE/PLST) blends at different compositions were produced in the presence of azodicarbonamide (ACA) compound as foaming agent. The LDPE/PLST blends before and after electron beam irradiation were investigated in terms of mechanical properties, bulk density, and structure morphology. Moreover, the biodegradability of these materials was evaluated by the soil burial test for 2 months, in which the buried sheets were also examined by scanning electron microscopy (SEM). The results showed that the increase of PLST content from 24 to 30% was accompanied by a decrease in the yield and break stresses of 10 and 20% for the unirradiated blends without the foaming agent, respectively. Further decrease in these mechanical parameters was observed after the foaming process. The bulk density, void fraction, cell size measurements as well as the examination by SEM illustrate clearly the cell growth of the foam structure. The soil burial test and SEM micrographs indicate the growth of microorganisms overall the blend sheets and that the blend was completely damaged after two months of burying. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

垃圾土蠕变-降解沉降特性试验研究

为了研究垃圾土蠕变降解沉降特性,选取重庆市某垃圾场典型试样,基于室内蠕变观测试验得到蠕变降解沉降过程曲线（0~330 d）,建立了符合其沉降变形特性的PTH计算模型,验证了该模型合理性,同时对沉降影响因素进行了详细分析。结果表明,因外部应力和内部蠕变降解引起的沉降总量可达试样高度的33.2%,渗滤液在前期的溢出量受外部荷载和有机物含量的控制;垃圾土中有机物的降解规律可用Richards 模型来表示,累计沉降量和累计渗滤液产量之间符合指数函数关系;有利于初期压缩变形和后期降解沉降的最优有机物含量区间为29.1%～36.47%;内部温度监测结果显示,20～41 ℃是一个可加快内部有机物降解速率的温度区间,且在41 ℃时作用最大。     

一种假单胞菌SY5降解石油的动力学研究

为了确定石油降解菌对石油污染物的生物降解特性,选用分离得到的一株石油降解菌假单胞菌SY5,对其降解石油污染物的动力学特性进行了研究．研究结果表明,在30℃,pH=7．2的反应条件下,所筛选的SY5菌对石油具有良好的降解能力,降解石油的反应基本符合一级反应动力学,且随石油初始浓度的增大,SY5降解石油的速率减小,降解受到抑制．在生物降解的过程中,SY5的生长曲线具有明显增长和衰减曲线．在生长阶段,产率系数Y值为0．3873．在内源呼吸阶段,衰减系数bd值为0．1805d^-1,SY5菌自身氧化速度比较快．SY5生物降解石油Monod方程的最大比增长速率胁,和半饱和常数Ks分别为1．6d^-1和150mg／L．     

芽孢杆菌L-510生物降解原油的特性及现场应用

为提高原油采收率,利用芽孢杆菌L-510对原油进行生物降解,经室内特性分析实验表明,经芽孢杆菌L-510处理后,原油中轻组分范围变宽,非烃组分含量平均增加2．09％,沥青质含量平均下降1．29％;原油含蜡量平均降幅为17．6％,胶质含量平均降幅为26．5％;原油的流动性得到改善,粘温曲线初始表观粘度与处理前相比降幅达50％。用该菌在葡北油田进行微生物吞吐现场试验,生产井经该菌处理4个月后,有效井达到80％,产液量增幅43．8％,产油量增幅51．4％。该菌株可广泛应用于采油工程领域,特别是微生物强化采油领域。     

邻苯二甲酸酯鼓泡生物降解

该课题测试了邻苯二甲酸酯类化合物的鼓泡生物降解行为。结果表明，邻苯二甲酸酯的降解速率常数（kb)与其烷基链长度之间存在良好的相关性，kb=0.0009x^2-0.019x 0.1123，相关系数r=0.9906；浓度超过500mg/L时，邻苯二甲酸二乙酯可抑制自身的生物降解；中间产物邻苯二甲酸浓度超过50mg/L时，也对邻苯二甲酸二乙酯的生物降解有明显的抑制作用。     

用瓦勃氏呼吸仪测定橡胶废水可生化性

本文介绍了利用瓦勃氏呼吸仪进行橡胶废水测定的过程和方法,并用配制的橡胶废水进行了二组实验,认为橡胶废水是易生化的,并对氧化率计算方法提出了修正,使之更接近于实际情况。     

微波辐射制备阿拉伯胶接枝2-丙烯酰胺基-2-甲基丙磺酸高吸水树脂及溶胀性能

以阿拉伯胶(GA),2-丙烯酰胺基-2-甲基丙磺酸(AMPS)为原料,N,N-亚甲基双丙烯酰胺(NMBA)为交联剂,过硫酸钾(APS）为引发剂,采用微波辐射方法制备了GA-g-PAMPS 高吸水性树脂。探讨了单体配比、交联剂用量、引发剂用量、中和度、微波功率和辐射时间对吸水倍率的影响,研究了树脂的溶胀性能,并用FTIR对吸水性树脂的结构进行了表征。结果表明：最佳合成条件下树脂吸去离子水倍率为683g/g,吸生理盐水倍率为137g/g。树脂的吸水倍率随着无机盐溶液浓度的增加而减小,在不同价态金属离子盐溶液中,树脂的吸水倍率顺序为NaCl>BaCl2> FeCl3,树脂具有较高的吸水速率和较好的重复吸水性能。     

玉米赤霉烯酮生物脱毒及关键酶作用机理的研究进展

玉米赤霉烯酮(Zearalenone,ZEN,ZEA)是由镰刀菌属产生的一类具有类雌激素生物活性的霉菌毒素,广泛存在于玉米、小麦等谷物及其制品中。本文综述了各类微生物降解ZEN的研究现状,重点比较其脱毒效率及产物毒性,尤以不动杆菌(Acinetobacter sp.SM04)、粉红粘帚菌(Gliocladium roseum IFO 7063)、毛孢子菌(Trichosporon mycotoxinivorans)和假单胞菌(Pseudomonas sp.ZE-1)研究较为全面,进一步总结了ZEN降解的关键酶及其作用机制,为微生物降解玉米赤霉烯酮的研究提供依据,也为大环内酯化合物和芳香族化合物的降解开拓更广泛的途径。