一株苎麻脱胶优势菌的筛选及发酵条件的初步研究

从麻园土中分离出60株能分解果胶的菌株.通过多次筛选获得4株果胶酶高产菌株.其中,菌株C-9被确定为优势菌,对其发酵培养基的初始pH值、发酵温度、发酵时间及接种量进行优化,结果表明该菌株在接种量为5%、pH值为7.5、温度为35℃、时间为36 h的条件下果胶酶活性达到305.62 U·mL-1,比优化前提高了1倍.     

近年纤维素降解菌株筛选研究进展

简述了近年来纤维素降解菌株筛选的研究进展,目前筛选到纤维素降解菌的真菌主要有木霉属Trichoderma、青霉属Penicillium和曲霉属Aspergillus,细菌主要是芽孢杆菌属Bacillus、放线菌主要是链霉菌属Streptomyces.重点介绍了筛选到的纤维素降解菌的菌株名称、菌株种属鉴定、菌株筛选来源、...     

太空育种对喜树内生真菌的影响

对已经筛选出来的喜树菌株EFCI—03进行太空育种实验,研究太空育种对喜树内生真菌生长特性以及产喜树碱能力的影响,发现太空诱变作用使第一代菌株具备生长较快的优势,但这种优势不具备可遗传性,并且菌株的产喜树碱能力没有明显变化。     

五氯苯酚降解菌体固定化及降解动力学

五氯苯酚(PCP)是一种曾被广泛使用的木材防腐剂、杀菌剂和除草剂,目前已经造成了世界范围内土壤和水体的污染。本文针对筛选的4种优势菌株NERCDT-A、NERCDT-B、NERCDT-C、NERCDT-D,通过正交实验考察不同固定化材料、溶液pH值和生物接种量,确定出适宜的菌株固定化包埋条件。分别用游离单株优势菌和固定单株优势菌对PCP进行降解实验研究,对比结果表明固定化的菌株表现出了较好的降解效果。通过固定化菌株对PCP的降解动力学研究,确定不同固定化菌株的Monod参数。     

好氧优势菌株分离及其对垃圾渗滤液中有机酸性物质的降解研究

分离筛选能够快速降解垃圾渗滤液中难降解有机酸性物质的优势茵种8株,研究了这8菌株及其混合体对苯甲酸、苯酚、邻苯二甲酸、脂肪酸等以垃圾渗滤液中常见的有机酸性物质的降解特性.这8株高效单一菌株中3株为细菌,2株为真菌,3株为放线茵.研究结果表明,8菌株对有机酸性物质的降解效果均有不同,不同菌株对不同有机酸性物质有最佳的降解效果,在特定的条件下可降解至最低甚至到零.混合菌群对芳香有机酸性混合物的降解效果最好,反应48 h内芳香类酸性物质产生的COD去除率为74.7%.     

卡泊芬净合成前体Pneumocandin Bo的发酵工艺研究

以Pneumocandin B0 PB5-31为出发菌株,从筛选高产菌株和提高产物中有效组分的比例两方面进行研究,以期提高Pneumocandin B0 的发酵水平.结果表明,紫外线诱变复合氯化锂后处理筛选出高产菌株,其发酵效价比出发菌株提高了72％；发酵培养基中添加0.3％的脯氨酸很好地提高了有效组分B0的比例.     

卡泊芬净合成前体Pneumocandin Bo的发酵工艺研究

以Pneumocandin B0 PB5-31为出发菌株,从筛选高产菌株和提高产物中有效组分的比例两方面进行研究,以期提高Pneumocandin B0 的发酵水平.结果表明,紫外线诱变复合氯化锂后处理筛选出高产菌株,其发酵效价比出发菌株提高了72％;发酵培养基中添加0.3％的脯氨酸很好地提高了有效组分B0的比例.     

桔青霉产核酸酶P1菌种高效选育方法研究

为了提高产核酸酶P1菌种的筛选效率,研究了甲苯胺蓝-RNA(TB-RNA)平板筛选方法 ,考察了溶剂体系、甲苯胺蓝浓度、底物RNA浓度等对TB-RNA平板上核酸酶P1酶解圈的影响。结果表明,在甲苯胺蓝浓度为2.0×10~(-4)mol·L~(-1)、底物RNA浓度为0.1%时,于超滤水体系中29℃恒温培养,紫外诱变12h,核酸酶P1的酶活与酶解圈直径呈正相关关系。以酶解圈与菌落直径比1.71为指标,从116株诱变菌株中筛选出10株菌株;经过后期发酵验证,选育出6株优势菌株;通过发酵及遗传稳定性考察,6#菌株的酶活最高,为390U·mL~(-1),比原始菌株提高了29%。为工业化生产快速选育菌株提供了高效方法。     

紫外诱变柠檬酸生产菌黑曲霉的选育

初步研究了柠檬酸生产菌黑曲霉产柠檬酸的影响因素和培养条件,通过紫外诱变考察了出发菌株的受诱变性,统计了紫外诱变黑曲霉引起的生物学效应,在紫外诱变过程中筛选到一株稳定高产菌株10min-3,产酸增加了5.33%,可作为进一步诱变筛选的出发菌株.     

活性染料脱色霉菌的筛选及其脱色特性

利用马丁氏培养基从印染厂废水中筛选出具有脱色能力的霉菌,研究所筛选霉菌对26种不同类型活性染料的脱色效果,选取优势脱色菌株,研究其脱色特性;利用紫外-可见、气相质谱对优势脱色菌株脱色前后的培养液进行检测,分析其脱色前后波谱的变化,确定其基本的脱色机理;对优势脱色菌株进行基因测序,结合形态学特征,以确定其种属。结果显示,从印染厂废水中分离出3株霉菌,命名为YR01、YR02、YR03,分别对26种活性染料进行脱色试验,3株霉菌均对虎红、藏青M-GD、曙红B、胭脂红、绿KE-4BD、翠兰KN-G、艳兰X-BR具有明显的脱色效果,其中霉菌YR03对以上7种染料的脱色效果最优,菌株YR03对虎红脱色前后染液的光谱吸收峰变化明显,说明染料分子结构发生了破坏,存在着先吸附后降解的脱色机制,其他均为吸附脱色。对菌株YR03进行形态观察与基因测序,确定为1株黑曲霉菌。     

Field aflatoxin contamination of corn in South Georgia

The weather conditions in 1977 were generally not favorable for corn production in many of the southeastern states. A combination of stress factors, weather conditions, and insect damage was favorable for ear mold by species of theAspergillus flavus group.A. flavus was the dominant fungus in preharvest corn, and this led to extensive aflatoxin contamination.     

Foraging Leaf-Cutting Ants Learn to Reject Vitis vinifera ssp. vinifera Plants that Emit Herbivore-Induced Volatiles

Leaf-cutting ants (LCAs) are dominant herbivores of the Neotropics, as well as economically important pests. Their foraging ecology and patterns/mechanisms of food selection have received considerable attention. Recently, it has been documented that LCAs exhibit a delayed rejection of previously accepted food plants following treatment with a fungicide that makes the plants unsuitable as substrate for their symbiotic fungus. Here, we investigated whether LCAs similarly reject plants with induced chemical defenses, by combining analysis of volatile emissions with dual-choice bioassays that used LCA subcolonies (Atta sexdens L.). On seven consecutive days, foraging ants were given the choice between leaf disks from untreated control plants and test plants of Vitis vinifera ssp. vinifera L. treated with the phytohormone jasmonic acid (JA) to mimic herbivore attack. Chemical analysis revealed the emission of a characteristic set of herbivore-induced volatile organic compounds (VOC) from JA-induced plants. Dual-choice experiments indicated that workers did not show any preference initially, but that they avoided JA-treated plants from day five onwards. Our finding that A. sexdens foragers learn to avoid VOC-emitting plants, which are likely detrimental to their symbiotic fungus, represents the first evidence for avoidance learning in attine ants toward plants with induced defenses.     

真菌对重金属的抗性及机理研究

介绍了重金属污染地土壤中筛选的真菌1#菌和黑曲霉对重金属的抗性,确定不同重金属对不同菌体的M IC(最小抑制浓度),确定具有金属抗性的优势菌种。结果表明,Cu2+对黑曲霉和真菌1#菌的最小抑制浓度分别为300 mg/L和400 mg/L,Zn2+对黑曲霉和真菌1#菌的M IC(最小抑制浓度)分别为600 mg/L和800 mg/L。     

降解含油废水菌株的选育及性能试验

从被含油废水长期污染的活性污泥中筛选分离出能降解该废水的4种不同单一菌株。通过对各菌株降解能力的考察,其中菌株H1降解能力明显高于其它菌株。初步鉴定H1为假单胞菌属。该菌的最适合生长条件为:温度40℃,pH值为9,NaCl浓度为0.5mol/L。该菌株降解含油废水的最佳使用条件为:最佳菌体接种量为每100mL废水中投加2.0mL菌悬液;营养液中,生长因子是必需的营养成分;废水的碳氮质量比为3∶1时,H1菌株的降解率高出市售菌种的降解率20%以上,有效地解决了市售菌种因针对性不强而效果欠佳的难题,有望降低生产成本。     

白腐菌降解焦化废水的研究

介绍了白腐菌在焦化废水中的驯化生长和产酶条件优化,考察了白腐菌及其酶类对焦化废水的降解能力,结果表明:白腐菌在培养条件下能够产生白腐菌漆酶,是降解焦化废水中的多环芳香化合物的主要活性成分。经过白腐菌和活性污泥混合,得到较好的处理效果:实验时间内COD去除率达到89%,NH3-N达到88%,较单纯活性污泥效率高。     

Chemical Interactions Between Two Lichen-degrading Fungi

Many obligate fungal pathogens of lichens, the so-called lichenicolous fungi, seem to be tolerant of antibiotic lichen secondary metabolites. However, certain lichenicolous fungi are known to be strongly inhibited by chemical defenses of lichens, even those on which they are frequently found in nature. One of these fungi is Nectria parmeliae, an obligate lichenicolous fungus that is observed on many species of lichens. Field observations of this fungus in northern Virginia indicate a marked preference for the lichen Punctelia rudecta. Laboratory studies established that N. parmeliae is incapable of growing on tissues of this lichen unless they are first washed with acetone to remove phenolic defense compounds. It was determined that N. parmeliae can grow on P. rudecta in nature after another lichen inhabitant, a species of Fusarium, enzymatically degrades lecanoric acid (LEC), the dominant lichen compound of P. rudecta. Field studies in northern Virginia demonstrate that observed lichens harboring N. parmeliae generally also harbor the Fusarium sp. Furthermore, high performance liquid chromatography (HPLC) shows that LEC is completely degraded by Fusarium in 90 days, which permits growth of N. parmeliae. Taken together, these results suggest that some obligate lichenicolous fungi cannot colonize certain lichens unless there has been prior chemical processing of these lichens.     

Influence of oleoresin constituents fromPinus ponderosa andPinus jeffreyi on growth of mycangial fungi fromDendroctonus ponderosae andDendroctonus jeffreyi

Dendroctonus jeffreyi andD. ponderosae are morphologically similar sympatric species of pine bark beetles over portions of their geographic ranges; however,D. jeffreyi is monophagous onP. jeffreyi whileD. ponderosae is highly polyphagous. Both species carry a species of mycangial fungi that are also very similar in appearance. Growth of the two mycangial fungi and of the fungusLeptographium terebrantis (associated with the polyphagous and non-tree-killingDendroctonus valens) in the presence of oleoresin constituents of host and nonhost conifers was tested by placing individual chemicals on agar growth medium and by growing the cultures in saturated atmospheres of the chemicals. The fungus associated withD. jeffreyi showed greater tolerance for chemical constituents placed on the growth medium than the other two fungi, and growth after three days was enhanced by heptane, the dominant constituent ofP. jeffreyi oleoresin. Growth of all three species of fungi was reduced by the resin constituents when the chemicals were presented as saturated atmospheres. The results suggest that the influence of the tree on growth of the symbiotic fungi of the bark beetles during the initial attack process may be different than after colonization by the beetles is complete. The difference in the responses of the apparently related species of mycangial fungi may provide some new insight into the evolutionary history of these beetle/mycangial fungus/host tree systems.     

白腐真菌处理工业废水的研究进展

白腐真菌是一种对污染物有独特降解作用的丝状真菌。介绍了其特性、降解机理和优势,阐述了白腐真菌在难降解工业废水处理中的研究进展,并展望其发展趋势。     

白腐真菌对活性艳红X-3B脱色性能的试验

初步探讨了白腐真菌对偶氮染料活性艳红X-3B废水的脱色效果。试验过程在一种特制的白腐真菌生物反应器中进行。试验结果表明培养液的类型、碳源物质的浓度和温度对白腐真菌的脱色能力有重要的影响。培养液类型对染料的脱色效果有显著的影响,试验所用的第一种共培养液不但有利于脱色,而且具有很好的缓冲能力。低浓度碳源试验条件有利于增强和加速对活性艳红X-3B染料的脱色过程。白腐真菌是嗜热真菌,温度较高有利于脱色反应的进行。     

白腐菌在制浆造纸工艺中的应用

综述了白腐菌在制菜造纸工艺各阶段的最新应用研究进展,简单介绍了白腐菌制菜的可行性。