23GrazziotinA,PimentelFA,SangaliS,Jong-应用与环境生物学报.DOCVIP

两株芽孢杆菌降解羽毛的比较及抗氧化肽的初步分离* 李 雷1 冯 红1** 1四川大学生命科学学院 成都 61006 摘 要 枯草芽孢杆菌UMU4和短小芽孢杆菌SCU11是本实验室分离的野生菌株经诱变获得的，其分泌的蛋白酶在蛋白废弃物处理方面具有良好的应用前景为了从这两株芽孢杆菌中筛选出高效利用羽毛的最优菌株，本研究将UMU4和SCU11分别接种到羽毛培养基中持续发酵6天，通过每天测试羽毛降解率、可溶性蛋白浓度、氨基酸含量及抗氧化活性等指标来评价这两株菌对羽毛的能力发现SCU11能利用羽毛其羽毛降解率是UMU4的1.2倍，第五天时约有65%的羽毛转化为可溶性和氨基酸。此外，SCU11发酵液的ABTS自由基清除率和还原力均在第三天达到最大值，且显著高于UMU4羽毛发酵液。SCU11在第五天所产角蛋白和碱性蛋白的分别是UMU4的1.6倍和1.2倍，SCU11具有更强的羽毛能力的原因。在此基础上，来自SCU11的羽毛降解产物经HCl沉淀和疏水层析获得4个抗氧化肽组分，其中组分F3的抗氧化活性最高。为羽毛的资源化奠定基础CLC TQ925 : Q78 Comparison of feather degradation of two Bacillus strains and preliminary separation of antioxidant peptides* LI Lei, FENG Hong** College of Life Sciences, Sichuan Unversity, Chengdu 610065, China Abstract Bacillus subtilis UMU4 and Bacillus pumilus SCU11 were selected with higher protease activity from wild-type strain in our previous work. The proteases produced by these two strains showed good prospects in utilization of protein waste. To screen out the optimal strain for degrading feather from these two strains, SCU11 and UMU4 were inoculated in feather fermentation medium. The feather degradation rate, soluble peptide content, amino acid content and antioxidant activity were measured daily. It was found that SCU11 strain can utilize feather more effectively. Its feather degradation rate is about 1.2 times higher than that of UMU4. At the fifth day, about 65% of feather was degraded into soluble peptides. In addition, the ABTS radical scavenging rate and reducing power of the SCU11 fermentation broth reached the maximum values in the third day, which were significantly higher than those from UMU4 strain. Further, the activities of keratinase and alkaline protease produced by the strain SCU11 at the fifth day were 1.6 times and 1.2 times more than that of UMU4, which may be the reason for SCU11 to be better than UMU4 in feather degradation. Furthermore, four antioxidant peptide fragments were separated from the feather degradation products by SCU11 through HCl precipitation and hy