烷烃溶剂对耐有机溶剂极端微生物地衣芽孢杆菌YP1产胞外蛋白酶的影响

Effect of alkanes on the production of a solvent-stable extracellular protease by the organic solvent tolerant bacterium Bacillus licheniformis YP1

摘要:

考察了添加5％(V/V)浓度的正庚烷、正辛烷、正癸烷、十二烷、十四烷、十六烷等烷烃溶剂对耐有机溶剂极端微生物地衣芽孢杆菌(Bacillus licheniformis)YP1的生长及产胞外蛋白酶的影响。结果表明5％(V/V)浓度的各种烷烃溶剂对YP1蛋白酶的稳定性及菌体生物量均无显著影响, 正庚烷、正辛烷、正癸烷等溶剂显著抑制YP1产蛋白酶, 而十二烷、十四烷、十六烷能提高YP1产蛋白酶1倍以上。发酵液中十四烷的浓度(1％－8％, V/V)与蛋白酶的活力呈正相关性, 添加十四烷后发酵过程中蛋白酶活力的显著增加出现在菌体生长的对数后期。培养过程中添加十四烷能导致YP1菌体形态显著变小。首次报道了烷烃溶剂对极端微生物产蛋白酶的影响。

Abstract:

In this paper, the effect of 5% (V/V) n-alkanes (e.g, n-Heptane, n-Octane, n-Decane, n-Dodecane, n-Tetradecane and n-Hexadecane) on the growth and protease production of organic-solvent-tolerant- bacterium Bacillus licheniformis YP1 was studied. 5%(V/V) n-alkanes had no effect on the stability of YP1 protease. 5% (V/V) n-alkanes had no notable influence on the yield of strain YP1 but dramatically affected the protease production. The presence of n-Heptane, n-Octane and n-Decane deeply repressed the protease production; however n-Dodecane, n-Tetradecane and n-Hexadecane enhanced the protease production prominencely. The concentration of n-Tetradecane (1%-8%, V/V) had a direct ration with the protease production. The detailed experiments showed that the notable increase of protease activity appeared at the late logarithm of cultivation compared with the blank. The cell shape of YP1 strain remarkably decreased when grown in the presence of n-Tetradecane. This is the first report about the effect of n-alkanes on the protease production by the solvent tolerant bacterium.