Screening And Condition Optimization Of Sea Cucumber Protein Fermentation Strain

Among Marine creatures,sea cucumber has high edible and medicinal value.The most valuable part of sea cucumber is the body wall of sea cucumber which is rich in protein.It was found that most of the protein in sea cucumbers was collagen,accounting for about 70%of the total protein in body walls.Due to the wrapping effect of collagen,sea cucumber protein is difficult to be digested and absorbed,and the effective utilization rate is less than 20%And sea cucumber polypeptide is easy to be absorbed by the human body,has excellent solubility and stability,and has anti-oxidation,anti-fatigue,antibacterial,anti-tumor and other effects.Transforming sea cucumber protein into sea cucumber peptide is the key way to make full use of sea cucumber protein resources.At present,the preparation methods of sea cucumber peptide are increasingly diversified,but the main methods are still followed by enzymatic hydrolysis,direct extraction,chemical method and fermentation method.The preparation of sea cucumber peptide by fermentation has high efficiency and is not easy to produce toxic substances.However,the number of relevant microbial preparations related to the protein decomposition of sea cucumber is relatively small at present,and the decomposition effect is poor and the price is high.Therefore,in this study,sea water was used as the source to screen strains capable of independent fermentation of sea cucumber protein,optimize its fermentation conditions,track the fermentation products and compare with the current commercial fermentation strains of sea cucumber.Finally,commercial strains of Bacillus subtilis,Bacillus amyloliquefaciens,Lactobacillus plantarum,Leuconostoc mesenteroides and SW02 were prepared and inoculated in 200 m L of OD_600nm=1 broth,and cultured under the optimal growth conditions of each strain.The concentration of bacteria in fermentation broth at 0 h,6 h,12 h,18 h,24 h,30 h,36 h,42 h,48 h,54 h,60 h,66 h,72 h was determined,and the growth curve of the strain was made.The above experimental method was repeated to determine the content and p H value of water-soluble proteins in fermentation broth at 0h,1 h,2 h,3 h,4 h,5 h,6 h,12 h,18 h,24 h,30 h,36 h,42 h,48 h,54 h,60 h,66 h and72 h.The experimental results showed that when the fermentation balance was reached,SW02 had a higher concentration of bacteria and the minimum p H change during the fermentation process,and more water-soluble proteins could be obtained after the fermentation.Therefore,SW02 could tolerate higher salt concentration and achieve better fermentation effect in this fermentation environment.The peptide molecular weight distribution and amino acids content in the fermented liquid measurement,found in the decrease of molecular weight peptides during the fermentation process,amino acids,peptides degradation parts of the part after degradation of amino acids in fermented liquid,the part in strain of the body,amino acid content is the highest when54 h 189.52?mol/m L.At the same time,the antioxidant activity of the fermentation broth was measured.The highest DPPH scavenging rate was 48.66%at 30 h,the best scavenging effect of superoxide anion was achieved at 60 h after fermentation,and the best inhibitory effect of hydroxyl radical was 48.81 U/m L at 48 h after fermentation.Therefore,the fermentation broth had certain antioxidant effect.