Extraction and physicochemical characteristics of a red pigment produced by marine bacterium strain S - 9801

A red pigment that has better biological properties is produced by marine bacterium strainS- 9801. The extraction methods, physicochemical and toxicity of the pigment have been studied. Dissolubility of pigment in the five organic solvent has been tested, and ethanol is optimally chosen for extraction. Physicochemical characteristics of this pigment was stable. The absorbance of the pigment solution was no losing when put under natural light for 10 days or treated by UV for 30 minutes, color of the pigment unchanged after 100℃ hythere for 1 h or 80 ℃ xerother for 2 h. The median lethal dose (LD_50) of the rat by celiac injection was 670.04 mg/kg and minimum lethal dose of oral was greater than 2 000 mg/kg.

Isolation and characterization of a marine bacterium producing protease from Chukchi Sea, Arctic

A Gram negative bacterium Ar/W/b/75°25′N/1 producing extracellular alkaline protease was isolated from surface water of latitude 75°25′N, and longitude 162°25′W in Chukchi sea, Arctic. The strain can grow at the temperature range from 7℃ to 30℃, and grow better at 30℃. It can not grow at 40℃. Keeping certain salinity concentration in medium is necessary for cell growth. It grows well in medium containing salinity concentration from 0.5% to 10% sodium chloride. Glucose, sucrose and soluble starch can be utilized by the strain, among which glucose is the optimal carbon source. Peptone is the optimal organic nitrogen source for cell growth and protease producing, and ammonium nitrate is the optimal inorganic nitrogen source. About 75 7% of total protease of the strain are extracellular enzyme. Optimal temperature for proteolytic activity is at 40℃. Protease of the strain keeps stable below 40℃, and shows high proteolytic activity within the pH range from 7 to 11.

Enhancing production of a 24-membered ring macrolide compound by a marine bacterium using response surface methodology

A 24-membered ring macrolide compound,macrolactin A has potential applications in pharmaceuticals for its anti-infectious and antiviral activity.In this study,macrolactin A was produced by a marine bacterium,which was identified as Bacillus subtilis by 16S ribosomal RNA(rRNA) sequence analysis.Electrospray ionization mass spectrometry(ESI/MS) and nuclear magnetic resonance(NMR) spectroscopy analyses were used to characterize this compound.To improve the production,response surface methodology(RSM) involving Box-Behnken design(BBD) was employed.Faeces bombycis,the main by-product in sericulture,was used as a nitrogen source in fermentation.The interactions between three significant factors,F.bombycis,soluble starch,and(NH4)2SO4 were investigated.A quadratic model was constructed to fit the production and the factors.Optimum medium composition was obtained by analysis of the model.When cultivated in the optimum medium,the production of macrolactin A was increased to 851 mg/L,2.7 times as compared to the original.This study is also useful to find another way in utilizing F.bombycis.

Studies on culture condition of new marine bacterium Zooshikella sp. SY01

New marine bacterium Zooshikella sp.SY01,producer of prodigiosin,was isolated from the seawaters of Sanya Bay.The culture conditions of this bacterium were investigated.Zooshikella sp.SY01 was cultured in 2216E media which contained tryptophan,histidine,lac-tonic acid,camphor,limonene,casein,diphenyl guani-dine,coumarin and 1,3-dinitrobenzene,respectively.After 5 days cultivation,the extracts of different culture broths were detected by direct infusion mass spectroscopy using positive ESI mode.As the results,tryptophan,his-tidine and casein didn't show any observable influences on the biosynthesis of prodigiosin.Lactonic acid,camphor,limonene,diphenyl guanidine,coumarin could inhibit the bacterium growth and prodigiosin biosynthesis to a cer-tain extent,slower the culture broth to turn red.However,1,3-dinitrobenzene inhibited the bacteria to produce pro-digiosin completely.MS data suggested that various metabolites with chemodiversity were produced in differ-ent culture media.In particular,a series of high-molecu-lar-weight compounds with high relative abundances were observed in the medium containing limonene.To further optimize the culture condition,more new prodigiosin ana-logues and lead compounds can be obtained and the goal of"one strain-many compounds"can be achieved.