Identification And Fermentation Optimization Of Strain HB01078,HB01085 With Antitumor Activity

In this study, 28 strains of marine bacteria with antitumor activity were detected by MTT method again. 12 strains with stable antitumor activity were obtained. In this foundation, the shape observation, physiological and biochemical characteristics and medicine sensitive examination were studied about the 12 strains.Strain HB02037, HB01078 and HB01085 had stronger inhibitory activities against tumor cell, while low inhibitory activity was detected against human liver cells. So these strains were identificated. By studying the morphology, cultural characteristics, physiological and biochemical properties, 16S rDNA and phylogenetic tree, HB02037 was proposed as Bacillus pumilus. HB01078 was closely related to Corallococcus coralloides, the sequence similarity of 16S rDNA was 98.4%. But there were many evident differences of morphological characteristics between them, thus it should be affirmed farther. As for HB01085, the highest 16S rDNA sequence similaritiy was found with Aurantimonas coralicida (95.6%), and the evolutionary tree showed that strain HB01085 formed a monophyletic clade. Therefore it appeared to represent a novel species.The best optimal liquid fermentation conditions and medium components of strain HB01078 and HB01085 were researed. The effects of carbon source, nitrogen source, inorganic salt, primary pH value, temperature, seed cultural time, incubation volume, broth volumn, rotation speed and cultivation time on the production of antitumor bioactive compounds were studied. The optimized media of strain HB01078 consisted of 3% maizena, 0.5% glucose, 0.2% peptone, 1.2% yeast extract. The best culture conditions were: pH6.5~7.0, 2% inoculation amount, seed cultural time 24h, 28℃,150r/min for 3d. The optimized media of strain HB01085 consisted of 0.5% amidulin, 1.5% glucose, 0.2% peptone , 1.2% yeast extract. The best culture conditions were: pH7.0~7.5, 5% inoculation amount, seed cultural time 48h, 28℃,180r/min for 4d. Under the optimized conditions, the inhibitory rates of HB01078 and HB01085 against human liver cancer cell SMMC-7721 were 94% and 98% , respectively.