ABSTRACT
In the present study, we developed a two-liquid phase fermentation system by adding 1% n-dodecane as oxygen-vector to enhance the microbial lipids productivity of Trichosporon fermentans using cassava starch hydrolysate. Results suggest that the oxygen-vector could alleviate the oxygen shortage in flask fermentation. The cell mass and lipids concentration were 101.2 g/L and 50.28 respectively in 2 L fermenter with the presence of 1% n-dodecane. Additionally, gas chromatography analysis also reveals that the microbial lipids produced by T. fermentans contained a higher percentage of saturated fatty acid in the oxygen-vector case.
Subject(s)
Alkanes , Chemistry , Biofuels , Fermentation , Industrial Microbiology , Methods , Lipids , Manihot , Metabolism , Starch , Metabolism , Trichosporon , Genetics , MetabolismABSTRACT
Microbial oil, as raw material for biodiesel, can be produced by Trichosporon cutaneum B3 using cassava starch hydrolysate. Batch cultures demonstrated that there was little inhibitory effect with the concentration of cassava starch hydrolysate up to 90 g/L. The favorable initial pH, C/N molar ratio, nitrogen source and its concentration were 6.0, 116, yeast extract and 3.0 g/L, respectively. Under the optimized conditions, dry biomass reached 15.2 g/L and lipid content reached 40.9% after culture for 144 h in flask. Batch cultures in a 2 L stirred-tank fermenter were run for 44 h and resulted in dry biomass, lipid content and lipid yield of 28.7 g/L, 42.8% and 12.27 g/L, respectively. The chemical compositions of biodiesel prepared from lipids of T cutaneum B3 mainly included palmitic acid methyl ester, stearic acid methyl ester, oleic acid methyl ester and linoleic acid methyl ester etc., and its main physicochemical properties were in compliance with relevant national diesel standards. Therefore, the biodiesel prepared from lipids of T cutaneum B3 can serve as a potential fossil fuel alternatives.
Subject(s)
Biofuels , Culture Techniques , Methods , Fermentation , Industrial Microbiology , Methods , Lipids , Manihot , Metabolism , Starch , Metabolism , Trichosporon , MetabolismABSTRACT
A total of 127 strains of endophytic fungi were isolated from roots, branches and leaves of Huperzia serrata. These strains were identified into 19 genera based on morphological characters and ribosomal DNA (rDNA) sequence analysis, there into Penicillium, Aspergillus and Podospora were dominant populations in H. serrata. From analysis results we found some endophytic fungi showed a certain degree of tissue preference. The isolation rate and colonization rate of stems were both larger than those of leaf and roots. After testing the acetylcholinesterase (AChE) inhibitory activity of these endophytic fungi, a total of 39 endophytic fungi belonging to 15 genera showed AChE inhibition. Eleven endophytic fungi showed potent AChE inhibition, 7 of which were isolated from leaf. The research not only provided theoretical basis for developing and utilizing the resources of endophytic fungi in H. serrata but also showed a new path for searching medicines resource which has AChE inhibitory activity.
Subject(s)
Cholinesterase Inhibitors , Pharmacology , Fungi , Classification , Huperzia , MicrobiologyABSTRACT
The chemical composition of essential oil, which from the leaves of Chimonanthus grammatus obtained by hydrodistillation were analyzed by GC-MS, and their possible antibacterial properties were screened. According to the results from GC-MS analysis, fifty-three components comprising 99.99% of the essential oil were identified. The major components of essential oil were 3-(4, 8-dimethyl-3,7-nonadienyl)(E) -furan (13.1%), bornyl acetate (12.66%), and 6,6-dimethyl-3-methylene-bicyclo[3.1.1] heptane (7.06%), etc. Antibacterial activity of essential oil was employed by two complementary test systems of disc diffusion and MIC/ MBC tests, which showed obviously antibacterial activity against all of the tested bacteria.
Subject(s)
Anti-Bacterial Agents , Pharmacology , Calycanthaceae , Chemistry , Gas Chromatography-Mass Spectrometry , Methods , Oils, Volatile , Pharmacology , Plant Leaves , ChemistryABSTRACT
To investigate the energy utilization efficiency of Synechococcus sp. PCC7942 under mixotrophic conditions, we studied its growth characteristics in mixotrophic cultures with glucose and acetic acid respectively and discussed the carbon metabolism and energy utilization based on metabolic flux analysis. Results showed that both glucose and acetate could better enhance the growth of Synechococcus sp. PCC7942, and the latter was more effective. The metabolic flux through glycolytic pathway in mixotrophic cultures was stimulated by glucose whereas depressed by acetate, while the flux through the tricarboxylic acid cycle increased in both cases. Under mixotrophic conditions, glucose makes more significant impact on the diminishment of photochemical efficiency of Synechococcus sp. PCC7942. Although the contribution of light energy was smaller, the cell yields based on total energy in mixotrophic cultures were higher comparing with photoautotrophic culture. The energy conversion efficiencies based on ATP synthesis in photoautotrophic culture, mixotrophic cultures with glucose and with acetate were evaluated to be 6.81%, 7.43% and 8.77%, respectively.
Subject(s)
Acetic Acid , Pharmacology , Adenosine Triphosphate , Carbon , Metabolism , Culture Media , Culture Techniques , Methods , Energy Metabolism , Glucose , Pharmacology , Synechococcus , Classification , MetabolismABSTRACT
Metabolic flux analysis is a very powerful tool to understand CO2 fixation and light energy utilization of microalgae during photoautotrophic cultivation. A comprehensive network structure for the autotrophic growth of Synechococcus sp. PCC7942 was proposed, and the carbon and energetic metabolism under different incident light intensity was investigated based on metabolic flux analysis in this paper. These results showed that CO2 fixation was the main energy and reducing potential trap which accounted for 85% and 70% of the total energy and reducing potential consumption respectively. We also found that the cell yield and the maximum cell yield based on ATP synthesis were maintained 2.80 g/mol and 2.97 g/mol respectively under the appointed incident intensity. But the cell yield on absorbed light energy their corresponding energy conversion efficiency were descended with the increasing of incident intensity.
Subject(s)
Carbon , Metabolism , Carbon Cycle , Carbon Dioxide , Metabolism , Cell Culture Techniques , Energy Metabolism , Light , Photochemical Processes , Synechococcus , MetabolismABSTRACT
<p><b>OBJECTIVE</b>To analyze and compare the cell growth and accumulation of flavonoids and chlorogenic acid in the callus and suspension cell of Eucommia ulmoides.</p><p><b>METHOD</b>The callus induced from the leaf of E. ulmoides seedlings were suspended in liquid medium. The time courses of cell growth and yields of flavonoids and chlorogenic acid were studied.</p><p><b>RESULT</b>The highest contents of flavonoids and chlorogenic acid in the callus were 13.46, 1.712 mg x g(-1), respectively, while the contents of these two secondary metabolites were 16.63, 3.93 mg x g(-1) in suspension cell culture correspondingly.</p><p><b>CONCLUSION</b>Comparing with callus, the suspension cell showed a short growth period and high growth rate with a remarkable high content of flavonoids and chlorogenic acid.</p>