简青霉对酚类和苯胺类污染物的降解研究

在培养4 d的简青霉培养体系中,分别加入不同浓度的酚类和苯胺类物质,观察这些有毒物质对简青霉生长的影响,并研究简青霉对这几种有毒物质的降解效果.结果表明:低浓度的酚类和苯胺类物质能促进简青霉的生长,高浓度的这些物质则对简青霉的生长有一定的抑制作用.同时简青霉能够很好地催化氧化苯酚,2,4-二氯苯酚和苯胺.当苯酚质量浓度...     

从桔青霉M71生产核酸酶P_1及酶活提高途径的研究

由桔青霉Ｍ７１在２８±１℃下用深层通气搅拌发酵产生的核酸酶Ｐ１能降解热变性ＤＮＡ和酵母ＲＮＡ成为５＇－脱氧核苷酸和５－核苷酸。培养过程中酶活力高峰期在７０－９５ｈ之间，该酶对热变性ＤＮＡ和酵母ＲＮＡ的活力分别高达１５５ｕｎｉｔ／ｍｌ和３６９ｕｎｉｔ／ｍｌ，其最适作用温度为７５℃，最适ｐＨ值为５．０，在７０℃以下１ｈ之内稳定。发酵过程中控制接种量、氧气供应量、ｐＨ值及添加适量的Ｚｎ２＋，Ｆｅ２＋，Ｓｎ２＋，ＳＬ－Ｃｙｓｔｅｉｎｅ，Ｔｗｅｅｎ８０，泡敌等能促使酶活性大幅度增加     

绳状青霉及其代谢产物浸铀研究

本文开展绳状青霉直接浸铀研究,探索培养温度、培养时间、接种量对铀浸出率的影响;同时开展绳状青霉代谢产物浸铀研究,探索不同pH值的绳状青霉代谢产物的铀浸出率。结果表明,当培养温度为35 ℃、培养时间为3 d、接种浓度为0.1%时,绳状青霉直接浸铀的铀浸出率为70.13%;当绳状青霉代谢产物的pH值为2.6时,铀的浸出率达到峰值,为82.58%。     

偏甘油酯脂肪酶PrLip的重组表达及酶学性质表征

偏甘油酯脂肪酶因其独特的底物偏好性具有广阔的应用前景。研究从食品安全菌娄地青霉的基因组中发现了一个假定的偏甘油酯脂肪酶prlip基因,通过全基因合成技术获得该酶基因序列,并构建了PrLip组成型表达的毕赤酵母基因工程菌。工程菌在30℃发酵培养60h,发酵活力达到22.26U/mL。利用阴离子交换层析法纯化,获得纯度大于90%的脂肪酶PrLip。酶学性质研究发现该酶的最适反应温度为45℃,最适反应pH值为7.0,40℃的半衰期为6h,水解及酯化反应证实PrLip是一种偏甘油酯脂肪酶。脂肪酶PrLip具有良好的温度耐受性及对大多数表面活性剂的耐受性,使其具有广阔的工业应用前景。     

Citriperazines A-D produced by a marine algae-derived fungus Penicillium sp. KMM 4672

Abstract

Four new diketopiperazine alkaloids, citriperazines A-D were isolated from algae-derived Penicillium sp. KMM 4672. The structures of compounds 1–4 were determined using spectroscopic methods. The absolute configurations of compounds 1 and 4 were established by comparison of calculated and experimental ECD spectra. The cytotoxicity of compounds 1–4 against several human prostate cell lines was evaluated.     

(3R,4S)-isostreptenol III from Penicillium purpurogenum MM

Abstract

In continuation of the search for new compounds from the terrestrial fungus Penicillium purpurogenum MM, (3R,4S)-isostreptenol III (1), a further new natural compound is reported. The chemical structure of 1 was confirmed by extensive 1D and 2D NMR and ESI HR mass measurements, and by comparison with literature data. The absolute configuration was determined by ab initio calculations of ECD, ORD, and NMR data. The antimicrobial and cytotoxic activities of the crude extract and 1 were reported using a set of microorganisms and by the brine shrimp assay, respectively.     

木质纤维素降解酶系的基础和技术研究进展

山东大学微生物学科从事纤维素降解研究已有五十多年的历史。在木质纤维素微生物降解机理研究的基础上,从自然界中筛选到一株能高效降解植物纤维类生物质的斜卧青霉菌株,并获得该菌的多株抗降解物阻遏纤维素酶高产突变菌株。最近,已完成了对多株斜卧青霉菌株的全基因组测序,正在利用系统生物学技术深入探讨其酶系组成和酶合成调控机理。选育出的高产突变株,已用于规模化生产工业用酶,并开发出玉米芯生物炼制生产纤维素乙醇技术。     

从青霉菌丝体中提取核糖核酸的研究

文中研究了从青霉菌丝体中提取纯化核糖核酸的工艺条件。采用盐碱法破碎细胞,调抽提液 pH值至4.6以沉淀部分蛋白质,然后用中性蛋白酶AS1.398处理分级沉淀后的上清液,详细考察了蛋白酶用量、反应温度、初始pH值和反应时间对核酸纯度的影响。酶解液经截留相对分子质量为6.0×10⁴的超滤膜过滤后,核糖核酸的纯度和得率分别是72.1%和0.42%。     

Two new isochromane derivatives penisochromanes A and B from ascidian-derived fungus Penicillium sp. 4829

Seven polyketides, including two new isochromanes, penisochromanes A and B (1 and 2), as well as five known compounds were obtained from an ascidian-derived fungus Penicillium sp. 4829. Their structures were identified by extensive spectroscopic analyses. The structures of compounds 1 and 3 were further determined by the X-ray crystallography. Compounds 1 and 2 were the first example of isochromane with three adjacent oxy substituents in natural source. Compound 4 exhibited selective activities against two Gram-positive bacteria Staphylococcus aureus and Bacillus subtilis, with MIC values 6.25 and 12.5 μM, respectively.     

Encapsulation of Viable Aerobic Microorganisms in Silica Gels

The aim of this study was to develop techniques to sterilise the surface of silica gels containing encapsulated cells and the liquid broth they were immersed in, so that the observed metabolic activities could be unambiguously assigned to fully encapsulated cells. Gel surfaces were sterilised by UV-irradiation daily. The surfaces of the gels and the overlaying medium remained sterile for 20 days following irradiation, as demonstrated by the lack of visible surface growth and viable cells in the medium. We report the encapsulation of a viable, metabolically active, aerobic fungus Penicillium chrysogenum, and the aerobic Gram-positive bacterium Streptomyces rimosus in gels derived from aqueous silica sols. Carbohydrate consumption (catabolism) and antibiotic biosynthesis (penicillin or oxytetracycline) (anabolism) were monitored in both cultures, demonstrating that the encapsulated cells remained viable within the gel matrix. This demonstrates that the silica gels are sufficiently porous to sustain metabolic activities of aerobic cells, which require the diffusion of oxygen and other substrates within the gels nanopore network.