Lactobacillus Casei LT-L614 Was Cultured At A High-density Useing Cane Molasses And Its Preparation Research

In order to expand the application of sugar cane molasses and develop the medium suitable for industrial production for Lactobacillus casei LT-L614,the basic components of sugar cane molasses were studied as well as the effects of LT-L614 on the growth of sugar cane molasses by high density fermentation technology.Further,different LT-L614 synergist recipes were compared.This research will lay the groundwork for using sugarcane molasses as the fermentation carbon source,meanwhile it also provides theoretical reference for the development of high density culture of lactobacillus casei and the preparation of mushroom powder.The specific research work is as follows:1.According to the results of the composition analysis,the sugarcane molasses are consist of total sugar,sucrose,reducing sugar,moisture,ash,etc.The sugar cane molasses as a single carbon source for fermentation,it is proved that the sugarcane molasses has a good breeding effect as a single carbon source.Through the study of the pretreatment methods of molasses it was found that sulfuric acid-polyacrylamide precipitation as a pretreatment method for sugarcane molasses would achieve better results for the following LT-L614 fermentation.2.The medium composition of the LT-L614 was explored and optimized.Based on MRS,by the single factor and the Central Composite Design(CCD)response surface method,the optimal combination of the LT-L614 proliferation medium was achieved:80 g/L molasses,10 g/L soy peptone,15 g/L yeast powder,70 mL/L corn juice,8.5 g/L sodiumcitric acid,The highest number of living bacterium reached 9.61 ×109 cfu/mL.The single factor test was used to optimize the culture conditions of LT-L614,The results showed that initial pH 6.9,temperature 37 ℃ and inoculation amount 2%.By this way,the optimal medium and conditions were obtained for the high density proliferation medium fermentation.3.The high density culture technology of 5 L fermentor of LT-L614 was explored and optimized,Under the optimized medium and condition,the growth of LT-L614 in MRS and proliferation medium was studied,It was found that the proliferation medium mainly increased the number of viable cells by increasing the substrate concentration,and to extend the logarithmic period to achieve proliferation effect.To simulate the production in the 5 L fermentor,By optimizing the neutralizing agent and culture mode,The results showed that 20%NaOH was the best neutralizing agent,and the culture method was batch feeding.The linear relationship between the reducing sugar and time was studied and the parameters of the dynamic equation were obtained through linear fitting.on the basis of LT-L614 was fed with batches at 6 h,8 h,10 h and 12 h,each feeding 700 mL,Cultured for 24 h,The highest viable count was 9.12×1011 cfu/mL,while the biomass was 41.18 g/L,It is such an exciting result that it is two orders of magnitude higher than it used to be.4.Study on preparation of synbiotics by vacuum freeze drying technology of LT-L614.The formula was as follows:100 g/L skim milk,60 g/L mannitol,15 g/L L-tyrosine,and 50 g/L twain 80.Explore prebiotics before and after lyophilization of LT-L614,and freeze-dried process protection.The results showed that the oligosaccharides were the best,and the dosage was 20 g/L.Combined with the protective agent formula to prepare the synbiotics preparation.The proportion of the mixture and the prefreezing time of the sample were investigated,and the optimal ratio was 1:7.5 and the pre-freezing time was 5 h.By exploring the survival rate of different rehydration agents,it was found that different water-treatment agents had little difference.Finally,the number of live bacteria of lyophilized bacteria was as high as 9.8×1011 cfu/g,which was 2.3 times of the results of similar studies.5.The gastrointestinal environment tolerance of the synergistic agents was measured and the gastro:intestinal mimic tolerance of the synergistic agents and lyophilized cells was investigated.It was found that the survival rate of the 0.5 g preparation decreased by 5.37%compared with the untreated cells.And the total number of viable cells was still 109cfu/mL.It is proved that this biologic agent has less damage to the cell.The results were found to be consistent with the gastrointestinal tract tolerance of the two commercially available probiotic preparations reported.