ABSTRACT
Statistic-based experimental design was used to optimize the culture conditions for Pseudomonas aeruginosa ME16 strain which is capable of utilizing methane.Effects of inoculum volume,temperature,methane content,and initial pH of media on cell growth were studied with the medium of mineral salt and methane gas,and the response surface methodology(RSM) was then used to optimize culture conditions.The optimum conditions were as follows:temperature of 29.4℃,inoculum volume of 1.8% and methane content of 25%.Under the optimized culture conditions,the ME16 production was increased by 0.8 times and its cultivation time was reduced.The removal of methane gas by ME16 was preliminary investigated,and the removal rate of methane gas reached 65.7%.The results indicated that the strain was capable of removing of methane.
ABSTRACT
The potential of Rhizobium sp. N613 to produce the exopolysaccharide (REPS) was studied in this paper. Using an orthogonal design in a flask-shaker culture system, the fermentation medium and conditions of synthesizing REPS were optimized. Based on these results, the fermentation kinetic parameters were obtained in the batch fermentation with a 10L fermentor. The REPS yield of 11.31g/L was achieved by metabolic regulation during 40 h fed-batch fermentation. Transplanted tumor models of sarcoma 180 in mice were used to evaluate the anti-tumor effect. The result of anti-tumor activities showed that inhibition rate was 53.40%, when dose of REPS was 5mg/kg. These results indicate that REPS has the following properties: the short duration of fermentation, the high yield, the low cost, the effective immunocompetence and thickening. Thus, REPS has the value of development and application.