Regulatory effects of alanine-group amino acids on serine alkaline protease production by recombinant Bacillus licheniformis

2003-04-01
Çalık, Pınar
Bayram, A
Ozdamar, TH
Influences of the concentration and addition time of alanine-group amino acids, i.e. alanine, leucine and valine, on serine alkaline protease (SAP) synthesis were investigated by Bacillus licheniformis (DSM 1969) carrying pHV1431::subC in a defined medium to identify the amino acids creating intracellular reaction-rate limitation in SAP production. While the precursors of alanine-group amino acids, pyruvate and alanine, did not affect SAP production considerably within the range 0-15 mM, the addition of leucine decreased both SAP production and cell formation, because of the inhibition of valine synthesis. Although valine inhibits reactions starting with pyruvate towards 2-oxo-isovalerate, due to conversion of valine into 2-oxoisovalerate and from 2-oxo-isovalerate to leucine, valine did not inhibit leucine synthesis. Val (7.5 mM) supply at t = 0 h increased SAP activity to an activity of 1070 units - cm-' which was 1.3-fold higher than that of the reference production medium. The highest cell growth yield on substrate (Y-X/S) was obtained as 0.24 g . g(-1) with the supply of alanine; and the highest product formation yield on substrate was obtained as 0.134 units . g(-1) with the supply of valine. By using the results obtained, strategies for increasing SAP production and complex medium design were also discussed.

Citation Formats
P. Çalık, A. Bayram, and T. Ozdamar, “Regulatory effects of alanine-group amino acids on serine alkaline protease production by recombinant Bacillus licheniformis,” BIOTECHNOLOGY AND APPLIED BIOCHEMISTRY, vol. 37, pp. 165–171, 2003, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/51293.