Study On The Protential Probiotic Yeasts Based On High-throughput Screening Of Absorption And Tolerance To Pb²⁺ And Its Characteristics

With the growing threat to human and animal health aggravated by heavy metals in environmental pollution,research in Pb²⁺tolerance and adsorbent of potential probiotic yeast has received more concerns.In this paper,a high throughput rapid activation,high Pb²⁺tolerance and adsorbent yeast screening method based on Deep-well Plate?DWP?was established.Classification and identification of excellent strains by analyzing physiological and biochemical characteristics and 26SrDNA gene fragments.Rescreening with resistance and probiotics,The influencing factors and optimization experiments of Pb²⁺adsorption on the best strains by high throughput response surface method were studied,the adsorption isotherms and adsorption kinetics were also studied.The results are as followed:?1?All strains were isolated from 19 samples which were collected from heavy metal pollution area in Inner Mongolia,the high throughput screening indicated that 26 strains yeast in 104 isolated possess high tolerance of Pb²⁺over than 5000mg/L,4Wickerhamomyces anomalus,3 Rhodotorula mucilaginosa and 2Metschnikowia chrysoperlae among them are usually used in human and animals.?2?In these 9 strains,similar tolerance and adsorbent can be found between strains of the same genus,and their tolerance was upgraded after domestication;for Pb²⁺removal rate,however,5 of them were declined,3 of them were increased.the remaining strain was not changed.?3?Correspondence between tolerance and adsorbent was not found in 9strains,removal rate of 2 low-tolerance Metschnikowia chrysoperlae can reach up to92.56%,removal rate of 3 high-tolerance Rhodotorula mucilaginosa only 23.14%,and Pb²⁺tolerance concentration of 4 Wickerhamomyces anomalus was in the scope of6000⁷000mg/mL,and their removal was 78.94%⁹1.67%.?4?Screened for potential probiotics from highly tolerant and highly adsorbed Pb²⁺of 5 strains:Wickerhamomyces anomalus QF-1-1 can well tolerate acid,alkali,hypertonic,high plumbum and bile salt stress.After continuous treatment of gastric and intestinal survival rate is still as high as74.43%,It also has a certain antioxidative stress and the ability to produce bile salt hydrolase.?5?The influence factors of Wickerhamomyces anomalus QF-1-1 adsorption on Pb²⁺were influenced by p H,initial mass concentration of Pb²⁺and concentration of cell.There was a significant interaction between the mass concentration of cell and the initial mass concentration of Pb²⁺.Through optimization:The maximum adsorption capacity of the strain was 19.22mg/g at 30?,initial p H value 6,cell mass concentration10.78g/L,adsorption time 45.07min,and Pb²⁺initial mass concentration of418.52mg/L.It is 2.15 times the amount of adsorption before optimization.The adsorption process of Pb²⁺conforms to Langmuir isothermal adsorption and quasi two stage adsorption kinetic linear regression equation.The results can provide excellent strains and data support for the research and development of new heavy metal biosorption agents.At the same time,the high-throughput method can also be applied to the cultivation and phenotype screening of aerobic microorganism.