ABSTRACT
Cyclodipeptide (CDP) composed of two amino acids is the simplest cyclic peptide. These two amino acids form a typical diketopiperazine (DKP) ring by linking each other with peptide bonds. This characteristic stable ring skeleton is the foundation of CDP to display extensive and excellent bioactivities, which is beneficial for CDPs' pharmaceutical research and development. The natural CDP products are well isolated from actinomycetes. These bacteria can synthesize DKP backbones with nonribosomal peptide synthetase (NRPS) or cyclodipeptide synthase (CDPS). Moreover, actinomycetes could produce a variety of CDPs through different enzymatic modification. The presence of these abundant and diversified catalysis indicates that actinomycetes are promising microbial resource for exploring CDPs. This review summarized the pathways for DKP backbones biosynthesis and their post-modification mechanism in actinomycetes. The aim of this review was to accelerate the genome mining of CDPs and their isolation, purification and structure identification, and to facilitate revealing the biosynthesis mechanism of novel CDPs as well as their synthetic biology design.
Subject(s)
Actinobacteria/metabolism , Actinomyces/metabolism , Biological Products/metabolism , Bacteria/metabolism , Diketopiperazines/metabolism , Amino AcidsABSTRACT
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
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
<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>
Subject(s)
Cell Culture Techniques , Cells, Cultured , Chlorogenic Acid , Metabolism , Eucommiaceae , Chemistry , Metabolism , Flavonoids , 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
The type of basic media and the contents of plant growth substances were investigated by orthogonal design experiment,and also the effects of different culture conditions on the growth of suspension cells and the accumulation of total flavonoids in Eucommia ulmoides were studied.The results showed that B5 medium supplemented with 0.5mg/L NAA,0.6mg/L 6-BA and 30g/L sucrose,at initial pH 5.0～5.5,20g(FW)/L inoculation quantity and 110 r/min of rotation speed was a preferable culture conditions for E.ulmoides suspension cells growth and flavonoids synthesis.The results of metabolic kinetics analysis for E.ulmoides cell suspension culture showed that the logistic and Luedeking-Piret equations can be used for describing the kinetics of cell growth,sucrose consumption and flavonoids production during the process.The maximum specific growth rate(?m),the actual growth yield based on sucrose(YG) and maintenance coefficient(m) were 0.417/d,0.619g/g and 0.0206g/(g?d-1) respectively.All these outcomes could give a basis for establishing the suspension cell culture of E.ulmoides and production of the natural active components in large-scale.
ABSTRACT
In this study,nearly 200 endophytic bacteria were isolated from different part of Huperzia serrata, over 60 bacterium with clear antifungal activity were selected from those cultures.Among them,strain H-6 exhibited the highest antifungal activity which was strongly inhibits the growth of many plant pathogenic fungi such as Sclerotinia scleroliorum,Fusarium graminearumt,Sclerotinia libertiana,Phytophthora capsici Leonia and Sesame fusarium wilt.According to the characteristics of morphology,physiology and biochem- istry tests and the comparison of 16S rDNA sequence,the strain H-6 was similar to the Burkholderia.So strain H-6 was identified as Burkholderia sp.H-6.The results also showed that Burkholderia sp.H-6 was markedly different from Burkholderia cepacia that was applied widely in agriculture as antagonistic bacteria. The medium and culture conditions of the strain all were optimized by single factor and orthogonal experiments.In the investigation of the culture condition,growth was carried out in a basal medium(potato juice)and gradually supplemented with the various ingredients to be investigated.The major ingredients be- ing investigated included carbon sources and nitrogen sources.The optimal antifungal activity production condition is growth in a medium(potato juice with 2.5%mannitol and 0.1%NaNO3),initial pH 4.0 at 28℃.