固态发酵苦荞制备多肽菌种的筛选

Screening of strains producing peptides from tartary buckwheat by solid-state fermentation

【目的】筛选固态发酵苦荞高产多肽及发酵产物液具有抗菌、抗氧化活性的菌株。【方法】采用米曲霉、酱油曲霉、雅致放射毛霉和少孢根霉分别对苦荞进行固态发酵,以蛋白酶活力、水解度、可溶性肽得率、抑菌率和体外自由基清除率作为筛菌指标。【结果】米曲霉固态发酵苦荞的可溶性肽得率最高达38.83%±1.18%,发酵产物液对大肠杆菌和金黄色葡萄球菌的抑菌率分别为96.62%±1.66%和97.54%±0.54%,同时羟自由基(·OH)清除率和二苯基苦味酰基苯肼自由基(DPPH·)清除率分别为55.65%±1.25%和10.84%±1.03%。对米曲霉发酵2 d发酵产物液的不同分子量分布及活性分析表明,分子量大小对抗菌及抗氧化活性有一定的影响。【结论】米曲霉可作为固态发酵苦荞制备多肽且发酵产物液具有抗菌及抗氧化活性的最佳菌株,并在多肽产量提升及抗菌、抗氧化活性的研究上具有巨大空间。

[Objective] Strain of tartary buckwheat by solid-state fermentation was screened for high peptides and their fermentation product liquid had antimicrobial and antioxidant activity. [Methods] Aspergillus oryzae, Aspergillus sojae, Actinomucor repens and Rhizopus oligosporus were respectively applied in tartary buckwheat by solid-state fermentation. The protease activity, degree of hydrolysis, soluble peptide yield, inhibition rate, and radical scavenging rate in vitro were regarded as evaluation indexes to verify target strains. [Results] Aspergillus oryzae was the optimal fermentation strain, the highest soluble peptides rate was 38.83%±1.18%, the inhibition rate of E. coli and S. aureus were 96.62%±1.66% and 97.54%±0.54%, the fermentation product liquid prepared the hydroxyl free radical（·OH） scavenging rate and the 1,1-diphenyl-2-picrylhydrazyl radical（DPPH·） scavenging rate were 55.65%±1.25% and 10.84%±1.03%, respectively. According to the different molecular weight distributions and activity analysis of liquid fermentation product of Aspergillus oryzae of 2 days demonstrated that different components molecular segments had an impact on antimicrobial and antioxidant activity. [Conclusion] Among these strains, Aspergillus oryzae was the most optimal strains which can be applied in tartary buckwheat by solid-state fermentation to produce peptides, and its fermentation product liquid had antimicrobial and antioxidant activity.