高产蛋白酶菌的筛选及其对螺旋藻发酵物活性的影响研究

Screening of high-protease-producing bacteria and its effect on the bioactivity of Spirulina fermentation products

为了更好地利用微生物发酵方法制备螺旋藻生物活性肽,从螺旋藻泥天然发酵液中筛选高产蛋白酶的菌株,并对其发酵产物进行了功能评价。形态观察和16S rRNA菌种鉴定结果显示,3株蛋白酶高产菌株分别为解淀粉芽孢杆菌、芽孢杆菌和短小芽胞杆菌。以3株菌及其混菌发酵螺旋藻,对所得发酵产物的3种活性成分(多肽、总黄酮和总酚)、4种抗氧化指标(DPPH自由基清除率、ABTS阳离子自由基清除率、铁离子还原力、总抗氧化能力)和血管紧张素I转移酶(angiotensin I converting enzyme,ACE)抑制活性进行了测定。结果表明单菌发酵和混菌发酵的产物中活性成分的含量及其抗氧化活性和ACE抑制活性均显著提高,以混菌发酵提高最为明显,效果最为优异,混菌发酵液中3种成分的含量分别提高305.2%、267.8%和164.2%;4种抗氧化活性指标分别提高611.5%、189.8%、354.4%、316.0%,ACE抑制活性提高102.6%。筛选获得的菌株在制备螺旋藻生物活性肽方面具有较好的应用价值和广阔的市场前景。

For the purpose of preparing Spirulina bioactive peptides more effectively by using microbial strains for fermentation,several protease producing bacterial strains were obtained from the natural fermented broth of Spirulina.Three protease high-producing strains were selected and identified by morphological and molecular biological method,which were Bacillus amyloliquefaciens LXZ1,Bacillus sp.LXZ2 and Bacillus pumilus LXZ3.The selected strains were used for Spirulina fermentation,the content of peptides,total flavonoids and total phenols in fermented product were measured,and antioxidant indexes(DPPH free radical scavenging rate,ABTS cation ion free radical scavenging rate,iron ion reduction power,total antioxidant capacity)and angiotensin I converting enzyme(ACE)inhibitory activity of the fermented products were evaluated.The results showed that the content of bioactive ingredients,antioxidant activity and ACE inhibitory activity significantly increased in the fermented products of single or mixed bacteria fermentation.Moreover,the mixed bacteria fermentation had the most excellent effect,with the content of these three bioactive ingredients increased by 305.2%,267.8%and 164.2%,respectively.The four antioxidant indexes increased by 611.5%,189.8%,354.4%and 316.0%respectively,and the ACE inhibitory activity increased by 102.6%.In conclusion,the selected strains in the present study have prospective application value and broad market prospect on bioactive peptides preparation from Spirulina.