Production of extracellular xylanases byPenicillium janthinellum

Xylanase production byPenicillium janthinellum using 10–100 mM of 2,2-dimethylsuccinate (DMS) buffer, in a range of pH 4.5-6.0 was studied. The enzyme activity was enhanced using oat xylan as the carbon source. Under these conditions a culture produced 1.14 Μmol/ min (11.4 U/mL or 84.4 U/mg) of Β-xylanase after 5 d of growth in a 10-mM buffer solution at pH 4.5. Protease was absent in the DMS buffer except when 100 mM phosphate buffer at pH 6.0 was used (4 U/mL). Β-Xylosidase was only found at a pH of 4.5 in all the buffer concentrations. At a 50 mM DMS buffer concentration at pH 4.5 Β- xylanases were induced by both oat and birch xylans, having a greater effect with oat spelt xylans. Electrophoretic analyses showed that the birchwood xylan induction exhibited different proteins profiles. No Β-xylosidase or Β- glucosidase was induced until d 5. The Β-xylanases were rapidly inactivated at 50‡C, however, birch xylanase appeared to be more stable than oat xylanase. Using oat xylan as an inductor, theΒ-xylosidase andΒ-glucosidase were 85 and 91 U/L, respectively, on d 7. The xylanase produced by induction from sugar cane bagasse hydrolyzate was used for pulp biobleaching. A 20% decrease on the Kappa value in Kraft pulp using the culture extract was obtained. These selective growth conditions led us to modulate the xylanase production for pulp delignification.     

Use of hemicellulose hydrolysate for β-glucosidase fermentation

Hydrolysis of cellulose byTrichoderma cellulases often results in a mixture of glucose, cellobiose, and low-mol-wt cellodextrins. Cellobiose is nonfermentable for most yeasts, and therefore it has to be hydrolyzed to glucose by β-glucosidase prior to ethanol fermentation. In the present study, the β-glucosidase production of onePenicillium and threeAspergillus strains, which were previously selected out of 24 strains, was investigated on steam pretreated willow. Both steam-pretreated willow and hemicellulose hydrolysate, released during steam explosion of willow, were used as carbon sources. Reference cultivation runs were performed using prehydrolyzed Solka Floc and glucose: The four strains were compared withTrichoderma reesei regarding sugar consumption and β-glucosidase production.Aspergillus niger andAspergillus phoenicis proved to be the best enzyme producers on hemicellulose hydrolysate. The maximum β-glucosidase activity, 4.60 IU/mL, was obtained whenA. phoenicis was cultivated on the mixture of hemicellulose hydrolysate and steam-pretreated willow. The maximum yield of enzyme activity, 502 IU/g total carbohydrate, was obtained whenAspergillus foetidus was cultivated on the hemicellulose hydrolysate.     

Lipase from a Brazilian strain ofPenicillium citrinum

A lipases (glycerol ester hydrolases E. C. 3.1.1.3) from a brazilian strain ofPenicillium citrinum has been investigated. When the microorganism was cultured in the simple medium (1.0% olive oil and 0.5% yeast extract), using olive oil in as carbon source in the inocula, the enzyme extracted showed maximum activity (409 IU/mL). In addition, decrease of yeast extract concentration also reduces the lipase activity. Nevertheless, when yeast extract was replaced by ammonium sulfate, no activity was detected. Purification by precipitation with ammonium sulfate showed best activity in the 40–60% fraction. The optimum temperature for enzyme activity was found in the range of 34–37°C. However, after 30 min at 60°C, the enzyme was completely inactivated. The enzyme showed optimum at pH 8.0. The dried concentrated fraction (after dialysis and lyophilization) maintained its lipase activity at room temperature (28°C) for 8 mo. This result in lipase stability suggests an application of lipases fromP. citrinum in detergents and other products that require a high stability at room temperature.     

Penicillin fermentation in a 200-Liter tower fermentor using cells confined to microbeads

The scale-up of the penicillin fermentation through cell confinement in a 200-L tower fermentor is described.P. chrysogenum spores were adsorbed into Celite microbeads having diameters greater than 180 Μm. Fed-batch fermentations were performed using both free and confined cells. Cell growth and penicillin concentrations were measured during the fermentation. In addition, the oxygen transfer rate, the aeration rate, and the level of dissolved oxygen were also measured. Significant improvement in the mass transfer coefficient was found when the cells were anchored onto the microbeads. This improved oxygen transfer rate was accompanied by higher production of penicillin at a lower aeration rate. Besides the improved oxygen transfer rate into the mycelial broth, a reduction of the energy input for the oxygen transfer was observed. The confinement of the cells to this microcarrier furthermore allowed the in-termittent harvesting of fermentation broth without reducing the cell mass in the fermentor.     

A new polyoxygenated farnesylcyclohexenone from Fungus Penicillium sp.

A new polyoxygenated farnesylcyclohexenone, peniginsengin A (1), was isolated from the fermentation of Penicillium sp. YIM PH30003, an endophytic fungus associated with Panax notoginseng (Burk.) F. H. Chen. The structure was assigned based on a combination of 1 D and 2 D NMR and mass spectral data. The cytotoxicity and antimicrobial activities of compound 1 were investigated.     

A new polyketide,penicillolide from the marine-derived fungus Penicillium sacculum

A new polyketide, penicillolide (1) was isolated from the fermentation broth of the marine-derived fungus Penicillium sacculum GT-308. Compound 1 is a polyketide with a unique carbon skeleton. The structure of this compound was established via extensive spectroscopic analyses including 1D-, 2D-NMR, and HRESI-MS.     

氧载体强化传氧的研究Ⅰ

以液态烷烃为油相对双液相发酵系统进行了研究，通过对体积溶氧系数Ｋ_Ｌａ及油相与水相理化性质的测定，对油相的加入提高发酵能力作了初步解释，并通过青霉素发酵，初步确定了油相体积分数为０．０２Ｌ／Ｌ时可提高青霉素生产能力。     

檀香及其宿主植物假蒿根中内生真菌的研究

研究目的：檀香（Santalum口舾“聊Linn．）为檀香科（Santalaceae）檀香属（Santalum）树种,属于常绿半寄生小乔木,其心材为传统名贵中药。檀香与其寄主植物假蒿通过根端的吸盘相连,探讨檀香与其宿主之间内生真菌的关系具有重要意义。创新要点：假蒿（KuhniarosmarinifoliaVent．）是幼龄檀香很好的寄主。目前已经对许多药用植物的内生真菌的分离和鉴定进行了大量研究,但是关于檀香和假蒿之间关系的研究报道较少。本研究首次探讨了檀香及其宿主植物假蒿根中内生真菌的数量和种类,为进一步研究两者之间的关系提供一些有用的信息。研究方法：采用组织块分离法从檀香的根和其宿主植物假蒿的根部材料分离内生真菌,并采用形态学鉴定和分子鉴定手段对分离的内生真菌进行鉴定。重要结论：从檀香的根和其宿主植物假蒿的根中160个组织块中分离和鉴定了共25个真菌类群,其中青霉属真菌Penicilliumsp．1为檀香根中优势菌,镰孢属真菌Fusariumsp．1为假蒿根中优势菌。特别有意思的是两种植物根中没有分离到明显相同的内生真菌。     

The Effects of Wheat Bran Composition on the Production of Biomass-Hydrolyzing Enzymes by Penicillium decumbens

The effects of the starch, protein, and soluble oligosaccharides contents in wheat bran on the extracellular biomass-hydrolyzing enzymes activities released by Penicillium decumbens mycelia grown in batch fermentations have been examined. The results showed increased starch content correlated directly with an increase in released amylase activity but inversely with the levels of secreted cellulase and xylanase. High amounts of protein in wheat bran also reduced the activities of cellulase, xylanase and protease in the culture medium. The effects of the soluble and insoluble components of wheat bran and cello-oligosaccharides supplements on production of extracellular cellulase and xylanase were compared. The soluble cello-oligosaccharides compositions in wheat bran were proved to be one of the most significant factors for cellulase production. According to the results of this research, determining and regulating the composition of wheat bran used as a fermentation supplement may allow for improved induction of cellulase and xylanase production.     

红树林植物尖瓣海莲内生真菌Penicillium sp.B21次级代谢产物的分离鉴定

研究了红树林植物尖瓣海莲叶内生真菌Penicillium sp.B21次级代谢产物。 用硅胶柱层析、制备薄层层析和重结晶等方法,从该菌发酵液的乙酸乙酯萃取相中首次分离获得5个单体化合物,运用现代波谱技术、单晶X射线衍射以及文献数据对照,鉴定其结构分别为8-羟基-6甲基-1-甲氧羰基酮(1)、大黄素(2)、ω-羟基大黄素(3)、(3R,4S)-6,8-二羟基-3,4,5-三甲基-3,4-二氢异香豆素(4)和3,6,8-三羟基-3,5,7-三甲基-3,4-二氢异香豆素(5)。 首次获得了sclerotinin B单晶结构。