Observation of the chemical structure of fructooligosaccharide produced by an enzyme fromAureobasidium sp. ATCC 20524

The chemical structure of the oligosaccharide produced from sucrose by an enzyme extracted fromAureobasidium sp. ATCC 20524 was observed. The GC-MS analysis by methylation indicated that this oligosaccharide is composed of 2-linked, 1,2-linked fructose and 1-linked glucose. The [¹³C]-NMR spectrum indicated that the 1,2-linked glycosidic linkages of fructose of this oligosaccharide are, and the 1-linked glycosidic linkages of fructose are . This investigation suggested that this oligosaccharide is isokestose.     

Production of pullulan from fuel ethanol byproducts byAureobasidium sp. strain NRRl Y-12,974

Summary Byproducts of fuel ethanol production from wet-milled corn, were tested as substrates for growth and pullulan production byAureobasidium sp. strain NRRL Y-12,974. The strain grew well on corn fiber and corn condensed distiller's solubles (CCDS), and fermented CCDS to pullulan. CCDS compared favorably with starch as a substrate for pullulan production.The use of brand or trade names may be necessary to report factually on available data. The USDA neither guarantees nor warrants the standard of the product, and the use of the name by USDA implies no approval of the product to the exclusion of others that may also be suitable. All programs and services of the USDA are offered on a nondiscriminatory basis without regard to race, color, national origin, religion, sex, age, marital status, or handicap.     

Production and properties of a cellobiose-oxidizing enzyme from a newly isolatedcellulolytic bacterium Cytophaga sp. LX-7

A cell-bound cellobiose-oxidizing enzyme was produced by cellulolytic Cytophaga sp. LX-7. It was found that both the cellulosic substrates and the soluble carbohydrate substrates tested promoted the production of the cellobiose-oxidizing enzyme, and the highest specific activities were obtained with cellulose powder MN300, carboxy- methylcellulose CM22, maltose and cellobiose. Among the nitrogen sources examined, peptone gave the best cellobiose-oxidizing enzyme production, whereas inorganic nitrogen sources gave very poor growth. The medium buffered with Tris/HCl, pH 7.1, yielded the highest levels of cellobiose-oxidizing enzyme activity and the temperature optimum for crude enzyme activity was 40°C.     

Production of fructosyltransferase by <Emphasis Type="Italic">Aureobasidium</Emphasis> sp. ATCC 20524 in batch and two-step batch cultures

A comparison of fructosyltransferase (EC 2.4.1.9) production by Aureobasidium sp. ATCC 20524 in batch and two step batch cultures was investigated in a 1-l stirred tank reactor using a sucrose supply of 200 g/l. Results showed that the innovative cultivation in two step of Aureobasidium sp. produced more fructosyltransferase (FFase) than the single batch culture at the same sucrose concentration with a maximal enzyme production of 523 U/ml, which was 80.5% higher than the one obtained in the batch culture. The production of fructooligosaccharides (FOSs) was also analyzed; their concentration reached a maximum value of 160 g/l the first day in the two-step culture and 127 g/l in the single-batch mode. The use of the two-step batch culture with Aureobasidium sp. ATCC 20524 in allowing the microorganism to grow up prior to the induction of sucrose (second step), proved to be a powerful method for producing fructosyltransferase and FOSs.     

Production of polyvinyl alcohol-degrading enzyme with Janthinobacterium sp. and its application in cotton fabric desizing

A strain capable of using polyvinyl alcohol (PVA) as sole carbon source was isolated from soil samples of a textile factory. The 16S rDNA sequence analysis cell morphology, physiology and biochemistry showed that it belonged to Janthinobacterium sp. This is the first report to show that the screened Janthinobacterium sp. could degrade PVA. The optimum nutritional and environmental conditions for PVA-degrading enzyme production by Janthinobacterium sp. were investigated by single-factor tests. Under optimized nutritional and environmental condition in shake flasks, PVA-degrading enzyme reached 5.12 U/mL at 21 h. With PVA-degrading enzyme produced by Janthinobacterium sp. WSH04-01, 80% of PVA could be degraded from cotton fabrics in 3 h.     

链霉菌G4溶菌酶的产生条件及特性

对链霉菌G4的产酶发酵条件和溶菌特性进行研究结果表明:蔗糖30 g/L、大豆蛋白胨12.5 g/L、牛肉膏2 g/L,对产酶最为有利;G4溶菌酶最适培养温度33 ℃,培养时间72 h,培养基初始pH 8.G4溶菌酶的最适作用温度和最适作用pH分别是55 ℃和6.5,多数金属离子会抑制G4溶菌酶的活性,其中Zn2+、Cu2+、Fe2+、 Pb2+几乎可以使其完全失活;对几种细菌、酵母菌的研究表明,G4溶菌酶对卵清溶菌酶不能作用的变形链球菌和金黄色葡萄球菌有很强的溶解活性.     

Acceptor reactions of a novel transfructosylating enzyme from Bacillus sp.

Many different oligosaccharides were produced by transferring the fructose residue of sucrose to maltose, cellobiose, lactose and sucrose (self-transfer), where their yields of fructosylated acceptor products accounted for 26–30% (w/w). The maximum conversion yield (30%) was obtained in fructosyl cellobioside formation with 500 g sucrose l^–1 (substrate) and 200 g cellobiose l^–1 (acceptor). These four acceptors gave various products having DP (degree of polymerization) 2–7 by successive transfer reactions.     

A thermostable lipolytic enzyme from a thermophilic Bacillus sp.: Purification and characterization

A thermophilic Bacillus sp. was isolated that secreted an extracellular, thermostable lipolytic enzyme. The enzyme was purified to 58 folds with a specific activity of 9730 units/mg of protein and yield of 10% activity by ammonium sulphate precipitation, Phenyl Sepharose chromatography, gel-permeation followed by Q Sepharose chromatography. The relative molecular mass of the protein was determined to be 61 kDa by SDS-PAGE and approximately 60 kDa by gel permeation chromatography. The enzyme showed optimal activity at 60–65 ^∘C and retained 100% activity after incubation at 60 ^∘C and pH 8.0 for 1 h. The optimum pH was determined to be 8.5. It exhibited 50% of its original activity after 65 min incubation at 70 ^∘C and 23 min incubation at 80 ^∘C. Catalytic function of lipase was activated by Mg⁺⁺ (10 mM), while mercury (10 mM) inactivated the enzyme completely. No effect on enzyme activity was observed with trypsin and chymotrypsin treatment, while 50% inhibition was observed with thermolysin. It was demonstrated that PMSF, SDS, DTT, EDTA, DEPC, βME (100 mM each) and eserine (10 mM) inhibited the activity of the lipolytic enzyme. With p-nitrophenyl laurate as a substrate, the enzyme exhibited a K _m and V _max of 0.5 mM and 0.139 μM/min/ml. The enzyme showed preference for short chain triacylglycerol and hydrolyzes triolein at all positions. In contrast to other thermostable Bacillus lipases, this enzyme has very low content of hydrophobic amino acids (22.58 %). Immunological studies showed that the active site and antigen-binding site of enzyme do not overlap.     

芽孢杆菌木聚糖酶的发酵条件研究

本文研究了芽孢杆菌Ｌ２３产木聚糖酶的时间曲线,碳源种类和浓度,添加物,发酵起始ｐｈ以及接种量对产酶的影响。该菌经３７℃培养５０小时,酶活力为３０ＩＵ／ｍｌ,酶最适反应温度为５７℃,最适ｐＨ值为７．０。     

新分离Microbacterium sp．XT11菌产黄原胶降解酶生产条件的优化研究

新分离Microbacterium sp．XT11菌能够合成黄原胶降解酶,将植物病原菌野油菜黄单孢菌分泌的毒素因子黄原胶分解,生成具有激发子和抗微生物活性的黄原胶寡糖。实验确认,黄原胶和酵母浸粉分别是XT11菌生产黄原胶降解酶的最适碳源和氮源,获得最高酶活力的最低碳源和氮源浓度均为0.3％。XT11菌生产黄原胶降解酶的最适条件为：培养温度28℃,培养基起始pH7.0,转速150r／min。     

Cyclic-AMP Production by Corynebacterium murisepticum No. 7 (ATCC 21374) and Microbacterium sp. No. 205 (ATCC 21376)

Corynebacterium murisepticum No. 7 (ATCC 21374) and Microbacterium sp. No. 205 (ATCC 21376) isolated from soil by the authors did not require purines for their growth and accumulated a large amount of cyclic-AMP (7~12mmoles) in the cultural medium, supplemented with adenine, hypoxanthine or their derivatives, but scarcely accumulated without these compounds, and d,l-alanine as a sole nitrogen source was not effective on cyclic-AMP production without these compounds

Four to five percent of glucose were the most effective on the production. Yeast extract and poly peptone were required for cyclic-AMP production.     

中国根霉12~#纤溶酶活力单位的测定

主要阐述了根霉纤溶酶活性 (效价 )的测定方法 ,采用血纤维蛋白平板法 ,在以尿激酶为参照标准的情况下 ,给出了根霉纤溶酶提纯各步骤的活性情况     

Production and properties of fibrinolytic enzyme fromStreptomyces sp. NRC 411

Of 16Streptomyces spp. investigated for the production of extracellular fibrinolytic enzyme, one species was chosen as the most promising producer. Using shaken cultures grown for 7 days, optimal conditions for enzyme production were pH 6.0, 5% (w/v) starch as carbon source, (NH₄)₂SO₄ and soybean flour as nitrogen sources and KH₂PO₄ at 1.2 g/l. Maximal activity of the crude enzyme was at pH 6.0 and 45°C. Holding the enzyme at 37°C for 2 h decreased the activity by only 10%.     

A synergistic reaction mechanism of a cycloalternan-forming enzyme and a D-glucosyltransferase for the production of cycloalternan in Bacillus sp. NRRL B-21195

Cycloalternan-forming enzyme (CAFE) was first described as the enzyme that produced cycloalternan from alternan. In this study, we found that a partially purified preparation of CAFE containing two proteins catalyzed the synthesis of cycloalternan from maltooligosaccharides, whereas the purified CAFE alone was unable to do so. In addition to the 117 kDa CAFE itself, the mixture also contained a 140 kDa protein. The latter was found to be a disproportionating enzyme (DE) that catalyzes transfer of a D-glucopyranosyl residue from the non-reducing end of one maltooligosaccharide to the non-reducing end of another, forming an isomaltosyl residue at the non-reducing end. CAFE then transfers the isomaltosyl residue to the non-reducing end of another isomaltosyl maltooligosaccharide, to form an alpha-isomaltosyl-(1-->3)-alpha-isomaltosyl-(1-->4)-maltooligosaccharide, and subsequently catalyzes a cyclization to produce cycloalternan. Thus, DE and CAFE act synergistically to produce cycloalternan directly from maltodextrin or starch.     

根霉纤溶酶发酵条件的优化

研究了不同培养基对中国根霉１２号（Ｒｈｉｚｏｐｕｓ ｃｈｉｎｅｓｉｓ１２）发酵生产纤溶酶的影响,发现Ｃ／Ｎ的降低有利于产酶,同时用正产实验给出了最佳培养条件为：以麸皮水＋胰蛋白胨＋豆渣为培养基,接种量２０％,转速１７０ｒ／ｍｉｎ;用响应面设计确定了最佳培养基为４．３６６６１％麸皮水＋０．９８９７５％胰蛋白胨＋４．８９８９５％豆渣;在最优条件下,纤溶酶的发酵效价可达３．０６Ｕ／ｍｌ。发现添加金属离子     

Growth and enzyme production of Cellulomonas sp. ATCC 21399 on microcrystalline cellulose. Effects of increasing concentration of a mineral medium

Summary The kinetics and production of different extracellular enzyme activities were studied during growth of Cellulomonas sp. ATCC 21399 on 2% Avicel with different concentrations of M9 mineral medium. The lag phase and the doubling time increased with increasing ionic strength of the medium. The highest cell density was obtained during growth at 5 x M9 mineral medium and Cellulomonas grew well at this high salinity. The enzyme activities against carboxymethylcellulose and xylan increased with increasing concentration of M9 medium up to 5 x M9. By contrast, activities against microcrystalline cellulose (Avicel), galactomannan and amylose decreased with increasing concentration of M9 medium. The extracellular proteinase activity increased with increasing concentration of M9 medium, and it is possible that the lability of the cellulolytic and amylolytic enzymes may be due to their susceptibility to proteolytic inactivation by the extracellular proteinases.     

Use of a lytic enzyme system from Cytophaga sp. in the lysis of Gram-positive bacteria

A lytic enzyme system from Cytophaga sp. has been used for lysis of the Gram-positive bacteria, Bacillus and Corynebacterium. The optimum pH and temperature for the lytic reaction were 9.2 and 50°C, respectively. The effect of substrate and enzyme concentration have also been studied. Protein release was followed and the potential of using bacteriolytic enzymes for large-scale cell lysis and release of intracellular material is discussed.     

Production of a fibrinolytic enzyme by thermophilic Streptomyces species

A strong fibrin-specific fibrinolytic enzyme was purified from the cell-free spent culture broth of a thermophilic organism, Streptomyces megasporus SD5. The strain could produce 150 mg crude protein per litre of spent broth, with a specific activity of 80 IU (Plough units) per milligram, within 18 h of incubation at 55 °C in glucose yeast/extract/peptone (GYP) medium, pH 8.0. For production of the enzyme, the strain could utilize different carbon and nitrogen sources with a C:N ratio of ∼ 1:2. The enzyme was stable at a broad range of pH ranging from 5 to 9, and highly thermostable with 50% activity after storage at 60 °C for 6 months. The enzyme belonged to the serine endopeptidase group. In vitro clot lysis revealed that the enzyme was active at 37 °C. This revised version was published online in July 2006 with corrections to the Cover Date.     

Production of phytate-hydrolysing enzyme by some fungi

Eighty-four fungi from twenty five species have been examined for the production of extracellular enzymes capable of hydrolysing phytate (3-phytase, myo-inositol hexakisphosphate 3-phosphohydrolase, EC 3.1.3.8, and 6-phytase, myo-inositol hexakisphosphate 6-phosphohydrolase, EC 3.1.3.26) when grown in: (1) rapeseed meal (RSM); (2) a semisynthetic medium containing phytate as the sole phosphorus source (PSM); (3) potato dextrose broth (PDB). Although 58 active strains showed substantial activity, results in either of the media were of no value in indicating activity in RSM. There was no relationship between the ability of a fungus to hydrolyse phytate and its taxonomic position. Aspergillus ficuum NRRL 3135 had the greatest activity in the synthetic medium, and was relatively active in RSM. The extracellular enzyme had maximum activity after 10 days growth in PSM and had a temperature optimum of 55°C. Two pH optima were noted at pH 2.0 and 5.5. Inorganic phosphate inhibited enzyme production; ammonia ions were a better nitrogen source than nitrate or urea.