| Hyperuricemia,defined as the blood uric acid levels beyond the normal,is a metabolic disease due to purine metabolic disturbance.Hyperuricemia often leads to gout attacks,and the occurrences of many other diseases such as urate nephropathy and lithangiuria,which caused seriously detrimental effects on patients' health and influenced their quality of life.The treatment of hyperuricemia must avoid habitual intake of purine-rich foods in addition to medical intervention.However,the high-purine foods are substantial in human diets,so it is difficult to maintain a nutrient balance in a purine-poor foods controlled diet.And it is almost impossible for patients to follow strict diet control in a long-term period.Using lactic acid bacteria(LAB)to prevent and/or auxiliarily treat hyperuricemia and its complications,the detrimental effects of people's living quality caused by maintaining strict dietary restriction could be reduced or eliminated.In this study,the purine nucleoside-decomposing ability of LAB were isolated from Chinese sauerkraut bought from market by high performance liquid chromatography(HPLC)method through the determination of their insosine and guanosine degradation abilities,and biological properties of isolates that with high degradation rate were evaluated.The main results of this study were as follows:(1)216 strains were isolated from Chinese sauerkraut by MRS medium,and their degradation abilities of inosine and guanosine were determined by HPLC.Among the isolates,strain 5,7,8,46,77 and 215 showed the highest degradation rate of insosine and guanosine.And their inosine and guanosine decomposing rate were:strain 5:89.37%and 93.20%,strain 7:68.36%and 58.16%,strain 8:93.43%and 95.98%,strain 46:66.20%and 78.14%,strain 77:100%and 100%,strain 215:100%and 100%,respectively.(2)Based on physiological,biochemical tests and 16S rRNA gene classification,strain 5 and 8 were identified as Lactobacillus curvatus,strain 7 as Bacillus sp.,strain 46 as Weissella hellenica,strain 77 as Enterobacter cloacae,and strain 215 as Lactobacillus brevis.Only strains that identified as LAB(strain 5,8,46 and 215)were further studied.(3)The biological properties of strain 5,8,46 and 215 were determined in this study.The antibiotic susceptibility of the four strains to 16 antibiotics was determined by the agar diffusion method.Spectrum antibiotic susceptibilities of these four strains were preliminarily understood.The tolerant abilies of strain 5,8,46,and 215 to acid,bile salt and artificial gastrointestinal solution were determined,and results showed that strain 8 and 215 were capable of surviving at a relative high level in the experiment.Strain 8 and 215 also showed the same high purine-nucleosides decomposing abilitie in the buffer and artificial intestinal solution.Therefore,strain 8 and 215 were considered as desirable strains that used to develop microbial agents with properties of preventing and auxiliarily treating hyperuricemia.(4)The high density culture method was applied to culture strain 8.Optimized conditions were obtained first:static culture,30?,1%inoculation size and pH 6.2.Carring out high density cuture of stain 8 through alkali neutralization process with only glucose added or both glucose and peptone added,the viable count of strain 8 was obtained as 1.15×109 cfu/mL and 1.540×109 cfu/mL,respectively.Conducting high density culture of strain via buffered salt method,a bacterial pupuation of 2.08×109 cfu/mL was obtained with 1.0%Na2HPO4 was added,and the population was 4.91 times of the original group.Compared with the alkali neutralization process,the buffered salt method had the advantages of easier operation,lower cost and better effect.Therefore,the buffered salt method is more suitable for high density culture of strain 8. |
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