极端微生物与工业生物催化剂开发

工业催化领域对生物催化剂提出了苛刻的要求,特别是高浓度底物或产物、高离子强度、酸碱条件及其非水相催化,如何获得高效的生物催化剂是催化技术发展的关键。极端微生物是高效工业生物催化剂的重要来源,本文主要介绍从嗜热菌、嗜盐菌或耐盐菌、耐辐射微生物、耐有机溶剂等极端微生物出发发现并开发高效工业生物催化剂,可望为生物技术的进一步发展提供一个更广阔的资源。     

F/F对嗜盐污泥以乙酸钠为底物生产PHB能力的影响

嗜盐混合菌生产PHB具有较好的成本优势。本研究接种入海口底泥发展嗜盐活性污泥,利用嗜盐活性污泥以两步法工艺生产PHB。在连续300 d的试验中从长期试验、发酵生产PHB以及表观动力学等方面探索了不同盛宴期/饥饿期(F/F)下筛选菌群的PHB积累能力。研究发现F/F作为重要的参数直接影响嗜盐活性污泥的PHB积累能力。在高F/F下非PHB积累菌群成为优势菌,而低F/F下促进高聚PHB嗜盐菌的选择和富集。在F/F≤0.33条件下筛选的嗜盐活性污泥最大PHB含量可以达到细胞干重的46.7%,PHB产率为0.358 mg PHB·(mg Ac)^-1。研究结果将对进一步实现嗜盐污泥生产PHB提供有益的指导。     

一株芽孢杆菌的分子鉴定及初步应用条件探究

引言嗜盐菌是生活在高盐环境中的细菌,多生长于盐湖、盐碱湖、死海、盐场和海洋中,腌鱼、咸肉等盐制品上也常有存在。通常嗜盐菌生长在盐浓度大于0.2mol.L-1的环境中[1]。我国西藏、青海     

细菌纤维素的合成原料多样性及其合成机制研究概况

概述了细菌纤维素合成原料的多样性、细菌纤维素的合成途径及其调控机制。综述了用于生产细菌纤维素的三种原材料及其研究现状,商业化碳源价格昂贵、大规模合成应优先考虑低廉的农副产品和工业副产物。阐述了细菌纤维素的合成是有多种相关酶参与的调控过程,主要包括糖的水解和转化,纤维素的合成以及最后的组装和分泌三个步骤。指出用低廉碳源物质作为原材料存在的问题及解决思路,并对细菌纤维素的大规模生产及开发应用进行了展望。     

二氧化氯空气净化剂的研究

目前市场上销售的空气清新剂一般只以散发香味来掩盖异味．不能净化空气．也不能杀灭空气中的细菌。一种优良的空气净化剂则不仅要具备杀灭各种有害微生物和消除有毒物质的特点,而且还应具备安全、高效、广谱、无副作用、储存和使用方便等长处。二氧化氯完全符合上述各项要求。二氧化氯的除菌性能在于它与微生物接触时能释放出新生态氧和次氯酸分子．对微生物细胞有较好的吸附性和穿透性．可有效地氧化细胞内含硫基的酶．破坏酶系统．同时使蛋白质中的氨基酸氧化分解．快速控制微生物蛋白质合成．达到抑制细菌的生长或杀灭的效果,     

细菌微生物对工业油田生产的危害及机理研究

细菌微生物在工业循环冷却水系统及油田回注水系统中大量繁殖,严重影响了正常生产运行。细菌微生物主要包括三类:硫酸盐还原菌、腐生菌及铁细菌。详细论述了细菌微生物对工业油田的危害,并阐述了三种细菌各自的腐蚀作用机理。     

微生物细胞工厂碳流调控进展

随着代谢工程技术的进步,越来越多微生物细胞工厂可用于化学品发酵生产。微生物细胞生产化学品具有生产条件温和、环境友好等优势,是实现化学品绿色可持续生产的重要手段。为了提高微生物细胞工厂的产量、得率和生产强度,传统代谢工程手段主要采用基因过表达或基因敲除方式增大目标代谢路径碳代谢流。然而由于代谢流调控精度不足,易导致细胞生产能力下降。本文主要针对微生物细胞工厂碳流调控中存在的瓶颈问题,从代谢流改造靶点选择、细胞生长与产物合成碳流平衡、副产物路径与产物合成竞争、产物合成效率强化四个角度,系统综述微生物细胞工厂碳代谢流调控的最新进展。并从高精度、仿生学、智能化、多任务、快响应调控工具的设计出发,对未来微生物细胞工厂的发展趋势进行展望。     

微生物表面活性剂的生产和潜在生物技术应用（待续）

微生物表面活性剂是两亲分子,其由亲水部分和疏水部分组成。根据其分子量的不同,可将其分为生物乳化剂和生物表面活性剂2大类。微生物表面活性剂根据其化学性质和制备所用的生物体的不同分成很多种类。这些生物分子由包括真菌、细菌和酵母在内的各类微生物所制备。其生产受到底物类型、发酵工艺和微生物菌株的显著影响。由于微生物固有的多功能特性和各种合成能力,微生物表面活性剂在很多工业和生物医学应用中比化学合成的表面活性剂更受青睐,包括生物修复(治理)、采油、作为洗衣粉配方成分,食品和化妆品行业中的乳液稳定剂。作为一种有前途的、具有广泛功能的生物分子,本文对微生物表面活性剂的生产及其在生物技术中的应用进行了综述。     

微生物生防制剂——威绿达VIRIDA研制和推广

浙江大学生物技术研究所研制推广的威绿达 (ＶＩＲＩＤＡ)菌肥主要应用于绿色蔬菜生产、旱地作物、草地保护 ,也可以作花卉肥料。由于生物制剂生防是以城市生活垃圾为基物 ,掺混入木霉、毛壳菌及有益的细菌生防制剂 ,因而它既含有作物生长所需的有机和无机成分 ,又具有防病促生长作用 ,并且可以改良土壤理化性质 ,是一种多功能的植物病害的生物菌肥。以绿色木霉为主 ,毛壳菌、枯草芽孢杆菌为辅混配制成 ,威绿达在国内外尚属首创 ,产品具有良好的应用前景微生物生防制剂——威绿达VIRIDA研制和推广     

pH对嗜盐混合菌发酵挥发性有机酸混合物合成PHA的影响

嗜盐混合菌发酵生产聚羟基脂肪酸酯（polyhydroxyalkanoate,PHA）具有免灭菌程序、产量高、易提取等优势而被广泛关注。集中考察了pH对嗜盐混合菌（MMCs）发酵混合挥发性有机酸（VFA）生产PHA的影响。研究结果表明,在6.5～8.2范围内pH对PHA合成没有明显影响,过高或者过低的pH都会降低PHA合成速率和VFA的吸收速率。发酵体系的pH影响了嗜盐MMC的PHA产量,但是在酸性和碱性条件下却存在不同的影响机制。碱性环境增大了VFA的解离程度,导致MMC对底物的吸收耗费大量的能量,造成VFA吸收速率的下降。这一作用在pH升高至9.2以上时表现显著。酸性环境下,分子态VFA进入细胞后改变了胞内的pH,降低了相关酶和蛋白质的活性,从而影响了底物的利用。当pH=5.2时微生物代谢及底物利用能耗量降低,导致PHA胞内降解利用率降低,刺激了PHA合成量的提高。PHA组分受pH影响不大,初始pH=5.2～10.2时羟基脂肪酸戊酯（hydroxyvalerate,HV）所占比例维持在34.9%～38.3%范围内。本研究对于进一步利用嗜盐MMC发酵含有混合VFA的废弃物生产PHA具有重要的指导意义。     

一株盐湖嗜盐菌的培养条件研究

嗜盐放线菌研究是极端环境微生物研究的重要组成部分,选择性采用高盐极端环境放线细菌新颖菌株进行菌株多种方式培养及次生代谢产物研究,有望找到新的有用化学结构.文章对一株分离自盐湖嗜盐菌的培养条件进行了研究,通过其平板及斜面培养情况、发酵培养情况、薄层层析技术显色等最终确定了其较为合适的培养基成分.     

Rapid differentiation of new isolates with MALDI-TOF mass spectrometry via discriminant function analysis based on principal components

Discriminant function analysis based on principal components was applied to the spectral outputs of whole cell suspensions of nine isolates from matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry. First, based on the salt tolerance and whole cell proteins, the similarity of the isolates to moderate halophiles was established. Intact microorganisms were then inferentially clustered by MALDI-TOF mass spectroscopy taking four type strains as precursors. Two of these type strains were moderate halophilic bacteria (Halomonas salina and Halomonas halophila), one was a mesophilic bacteria (Escherichia coli), and one was a halophilic archaea (Haloarcula vallismortis). Results showed that the isolates were significantly similar to halophiles but were different from a mesophile. This investigation demonstrates the feasibility of using whole cell suspensions for rapid differentiation prior to extensive experimentation.     

一株极端环境嗜盐菌的培养条件研究

文章对一株极端环境嗜盐菌的培养条件进行了研究,找到新的有用化学结构的机会将会是较大的,尤其是那些生存于极端环境中的放线菌将是可以广泛利用的天然产物源泉。通过其平板及斜面培养情况、发酵培养情况、薄层层析技术显色等最终确定了其较为合适的培养基成分。     

Die Kristallisationstheorie in der Praxis

Theory of crystallisation in practice. The use and applicability of crystallization theories for industrial crystallization practice are evaluated. The conclusion is that the plant user in particular benefits from the Population Balance Model because it allows for bug diagnostics and prediction of response on altering conditions. Also for design purposes, the available theoretical models greatly helped to increase insight into the wide range of events occurring in a crystallizer and how their interactions govern the resulting product. However, despite the enormous amount of research work done so far, the quantitative application of theoretical models has not found entrance into the design of tailor-made crystallizers for strictly defined particle size distributions. From a designer's point of view, further investments of time and money should be considered carefully because the actual state of knowledge already allows more than 80% of the encountered problems to be solved. One area of common interest that urgently deserves more attention in the near future is habit modification by additives.     

夹层玻璃的制造工艺及其生产和能源效率

夹层玻璃主要采用高压釜、多段辊压、间歇式/连续式真空层压、现场浇铸以及快速熔合射频层压工艺制造。比较了各工艺的主要设备、加工条件以及适合的产品和工业类型,强调生产效率和能源效率对层压工艺未来市场竞争力的重要性,初步分析了快速熔合射频层压等先进层压工艺对传统高压釜层压工艺的技术优势及其市场前景。     

海水板式换热器微生物污垢特性的实验研究

海洋生物附着及低速海流等因素直接影响海水换热器换热效果。为研究海水板式换热器的污垢特性,本文采用自行设计的板式换热器实验装置,通过富集培养并分离出硫酸盐还原菌（SRB）,使其附着海水板式换热器设备,并利用扫描电镜及热阻试验台,实验研究了附着污垢层的形成、生长及其换热特性,并对低流速海流环境下换热器的污垢热阻特性进行了对比实验。实验结果表明：污垢层的形成在不同时期其形貌和特征不同。能谱分析显示其组成的元素主要为C、H、O、Ca,是由各种有机物和悬浮颗粒组成。在诱导期后,污垢热阻符合渐进污垢增长模型,1 m/s以内的低流速下污垢热阻随流速增大而增大。     

Microbial corrosion of silicon nitride ceramics by sulphuric acid producing bacteria Acidithiobacillus ferrooxidans

Yttria/alumina doped silicon nitride ceramics were exposed to corrosive Acidithiobacillus ferrooxidans bacteria cultures. These microorganisms produce sulphuric acid as a metabolic product during thiosulfate oxidation. In this study, the effect of microbial corrosion of silicon nitride ceramics is compared with an abiotic-chemical corrosion process in sulphuric acid under similar conditions (e.g. pH, temperature and exposure time). While abiotic corrosion caused only partial lixiviation of the superficial grain boundary phase, microbially induced corrosion lead to an almost total dissolution of the amorphous grain boundary within the corrosion zone. Microbial corrosion is thus more efficient than the abiotic process: it dissolves more silica and causes therefore a higher corrosion rate. This is probably due to the additional microbial release of metal-chelating organic compounds that stimulate the corrosion process.     

Microbial inactivation by high-pressure

High-pressure treatments are receiving a great deal of attention for the inactivation of micro-organisms in foodstuff processing, pressure instead of temperature is used as stabilizing factor. In this context, high hydrostatic pressure treatment is the most studied alternative process, many works reported successful results in inactivating a wide range of micro-organisms under different operative conditions such as temperature, cycles of pressure, exposure time. Furthermore, a number of processes using high pressure treatment (HPT) has already been put into the market. Nevertheless this new technology presents the main limitation to be very expensive and difficult to control and manage because of the extremely high pressure employed, so that the widespread industrial diffusion in industry field appears cumbersome. The treatment with supercritical CO₂ could become a relevant alternative to HPT in the field of microbial inactivation of food as well as an innovative technique for the sterilization of thermally and hydrolytically sensitive polymeric materials in biomedical applications, such as polymeric particles for drug delivery or polymeric implants. It has been demonstrated that the effect of microbial inactivation assuring healthy food preservation is already consistent at pressures moderated (lower than 200 bar) when compared with those employed by traditional hydrostatic-pressure HPT methods (2000–7000 bar). In this work the anti-microbial potential of compressed CO₂ was investigated against gram-negative bacteria, gram-positive bacteria and spores; as model species, Pseudomonas aeruginosa, Bacillus subtilis and spores of B. subtilis were used. The experiments were performed in a semi-continous apparatus at different but mild operative conditions. Excellent results were obtained for micro-organisms, under appropriate conditions the survival ratio of bacteria could be reduced to about seven orders of magnitude. Inactivation of spores under the same conditions, found to be conflicting in open literature, was not satisfactory. Spore inactivation was possible by coupling combination of higher temperature and longer contact time conditions. The application of pressure cycles was also found to be beneficial.