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Objective: To investigate and optimize the fermentation conditions of an ocean-derived fungus, Alternaria sp. 114- 1G, and isolate metabolites in the fermentation products to explore antitumor compounds in the products via the structure elucidation and in vitro antitumor activity assay. Another aim of this study is to accomplish a fundamental work for further research on new compounds from Alternaria sp. 114- 1G. Methods: The in vitro antitumor activity was assayed for the crude extracts and isolated compounds by the CCK-8 method using a human cervical cancer HeLa cell line. The fermentation conditions were investigated and opti- mized based on the biomass of the fermentation and the in vitro antitumor activity of crude extracts of the fermentation. For the separation and isolation of metabolites, the column chromatography was performed on silica gel and Sephadex LH-20 columns, and semi-preparative high performance liquid chromatography(semi-HPLC)was conducted on a COSMOSIL C18-MS-Ⅱ column(10 mm×250 mm). The obtained compounds were identified according to the MS, 1H NMR and13C NMR data. Results: The relatively favored fermentation conditions were as follows: mannitol 25 g/L, maltose 15 g/L, glucose 10 g/L, monosodium glutamate 10 g/L, soybean peptone 5 g/L, yeast extract 3 g/L; 60% sea water in whole medium, initial pH 7.5; and fermentation at 10℃ for 15 days under a 150 r/min shaking speed on a rotary shaker. Four compounds 1-4 were isolated from the fermentation products of 114-1G strain and identified as cyclo (Gla-Tyr)(1), cyclo(Ala-Ile)(2), thymidine DNA nucleotide(3)and pachybasin(4). Among them, 4 showed a relatively stronger inhibitory activity on HeLa cells, with the 57.8% of inhibition rate at 100 μg/ml. Some other compounds were also isolated, and a phenolic one had been shown to be a new compound by a literature survey according to the planar structure deduced. Further studies on their structures were in progress. Conclusion: Fermentation conditions for Alternaira sp. 114-1G were investigated preliminarily, and four compounds 1-4 have been isolated from the fermentation products of the 114-1G strain. Among them, pachybasin(4)showed a relatively higher inhibitory effect on human cancer HeLa cells. Alternaira sp. 114-1G could produce new metabolites and the present study has provided a reliable groundwork for further research on new compounds from Alternaira sp. 114-1G.
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Background The Tibetan pig is a pig breed with excellent grazing characteristics indigenous to the Qinghai-Tibet plateau in China. Under conditions of barn feeding, 90% of its diet consists of forage grass, which helps meet its nutritional needs. The present study aimed to isolate and identify a cellulolytic bacterium from the Tibetan pig's intestine and investigate cellulase production by this bacterium. The study purpose is to provide a basic theory for the research and development of herbivore characteristics and to identify a source of probiotics from the Tibetan pig. Results A cellulolytic bacterium was isolated from a Tibetan pig's intestine and identified based on morphological, physiological, and biochemical characteristics as well as 16S rRNA analysis; it was designated Bacillus subtilis BY-2. Examination of its growth characteristics showed that its growth curve entered the logarithmic phase after 8-12 h and the stable growth phase being between 20 and 40 h. The best carbon source for fermentation was 1% corn flour, while 2% peptone and yeast powder compound were the best nitrogen sources. The initial pH during fermentation was 5.5, with 4% inoculum, resulting in a high and stable amount of enzyme in 24-48 h. Conclusions The isolated BY-2 strain rapidly grew and produced cellulase. We believe that BY-2 cellulase can help overcome the shortage of endogenous animal cellulase, improve the utilization rate of roughage, and provide strain sources for research on porcine probiotics.
Sujet(s)
Animaux , Bactéries/isolement et purification , Bactéries/métabolisme , Carboxyméthylcellulose de sodium/métabolisme , Sus scrofa , Intestins/microbiologie , Suidae , ARN ribosomique 16S/analyse , Fermentation , Concentration en ions d'hydrogène , AzoteRÉSUMÉ
Normal bacteria purification method was used in this study. Pseudomonas trivialis and Neurospora te-trasperma were screened from residues of traditional Chinese medicine (TCM). The fermentation conditions and flocculating function were also studied. The results showed that the selected strains grow well in the residues of TCM and their products can flocculate kaolin suspension solution. Based on these, we explored effects of various factors on the flocculated results in order to reveal the best fermentation condition among different combinations.
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Response surface methodology was used to optimize the fermentation conditions for the production of pristinamycin by immobilization of Streptomyces pristinaespiralis F213 in shaking flask cultivation. Seed medium volume, fermentation medium volume and shaking speed of seed culture were found to have significant effects on pristinamycin production by the Plackett-Burman design. The steepest ascent method was adopted to approach the vicinity of optimum space, followed by central composite design for further optimization. A quadratic model was built to fit the pristinamycin production. The optimum conditions were found to be seed medium volume of 29.5 ml, fermentation medium volume of 28.8 ml, and shaking speed of seed culture at 204 rpm. At the optimum conditions, a production of 213 mg/l was obtained, which was in agreement with the maximum predicted pristinamycin yield of 209 mg/l. This is the first report on pristinamycins production by immobilized S. pristinaespiralis using response surface methodology.
Sujet(s)
Fermentation , Pristinamycine/biosynthèse , Streptomyces/métabolisme , Techniques de cultureRÉSUMÉ
The microelements play an important role in the metabolism, therefore the supplementation of theses elements are necessary. The growth of Saccharomyces cerevisiae under aerobic and static conditions with the addition of chromic chloride to the cultivation medium were investigated. The studies showed that the addition of CrCl3 into the growth medium stimulate yeast biomass growth. The results showed that the maximum specific chromium up take was obtained under aerobic conditions 120 rpm, chromium conc. 200mg/l ,intact time 6hr, at pH 6 and temperature 35C0. Comparison between the aerobic and static conditions revealed that the priority of using the aerobic conditions. The tested parameters were found to be significant according to the selected design and student,s t- test .
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A suitable chemically defined culture medium was selected and some optimal conditions for the production of the highly immunosuppressive compound, cyclosporin A (Cyc A) are reported. Medium of the following composition was favorable for the production of Cyc A by Fusarium roseum: glucose, 30; NaNO3, 2; KH2PO4, 1; MgSO4.7H2O, 0.5 and KCL, 0.5 (g/l). Maximum productivity of Cyc A was achieved at pH 6.0 when 50 ml of the fermentation medium/250 ml flask, inoculated with five fungal agar discs (6 mm, diameter) of 7-days old F. roseum culture after incubation at 30 ºC at 120 rpm for 7 days.
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Using of clearing zones on pachyman agar medium, there are 217 plant endophytic actinomycetes, producing ?-1,3-glucanase were screened. 45.6% of the strains produced ?-1,3-glucanase, in which the strains from cucumber are up to 38. The percentages of endophytic actinomycetes from different hosts produceing ?-1,3-glucanases were different. The percentage of the strains in Rhizoma Polygonatum produced ?-1,3-glucanases is the highest, up to 88.9%. The Inhibited effects of plant endophytic actinomycetes which produced extracellular ?-1,3-glucanases on mycelium growth of Sclerotinia sclerotiorum were detected in vitro. Cucumber endophytic actinomycete gCLA4 strain was screened out from 99 isolates, which can strongly inhibit the growth of S. sclerotiorum. The optimal ?-1,3-glucanases fermentation conditions of strain gCLA4 were investigated, they were pachyman 0.2%, peptone as nitrogen, pH 7~8 for 5 days. The ?-1,3-glucanases of strain gCLA4 had some inhibiting efficiency on 13 plant pathogens, in which inhibiting efficiency to Botryosphaeria dothidea was the strongest.
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The optimum condition of shaking-flask p roducing enzyme were the tempe rature 26℃,initial pH 6 4,fermentation period 19 hours,medium volume 15mL m e dium/300mL Flask.soymilk-clotting enzyme was obtained from ammonium sulfate p r ecipitation.The optimum temperature and pH for the soymilk-clotting activity wa s 70℃and 5 8.The enzyme was easy to lose activity in acid or alkaline circumst a nce.About 60% of the original activity remained after 1 hour at 60℃.Ca 2+ ,Fe 2+ , Mg 2+ ,Na +increased the clotting activity,whereas Zn 2+ ,Al 3+ ca use inhibition.
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The fermentation conditions of high 1.3 -propanediol-producing strain E. aero-N-56 were determined in this Paper. The optimum conditions of producing 1.3-PD were: initial pH 7.0, temperature 30℃, culture time 48 h, inoculum size 9% . Under the optimum conditions: the 1.3-PD productivity reached up to 23.68 g/L?d; the 1,3-PD yield of E. aero-N-56 up to 47.36 g/L in 30 L fermentor.
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A high active soybean isoflavone glucoside hydrolase-producing mould strain was isolated from spirit qu. Its optimal hydrolase-producing conditions were as follows: 2.5% wheat bran as carbon source, 1% NaNO3 as nitrogen source, initial pH7. 0, culture medium volume 40mL/250mL, inoculating quantity 8% , culture temperature 30℃, revolutions 160r/min and culture time 84h. The enzyme activity reached 82 U/mL. Cu2+ can inhibit Absidia sp. R strain from producing the hydrolase, the influence of other metal ions was not remarkable on it.