Tipparat Hongpattarakere, Nucharee Seksun, and Areeya Suriya

pp. 255 - 265

Abstract

Isolation and screening of D-amino acid amidase producing bacteria from fifty-four soil samples
taken on Hat Yai campus of Prince of Songkla University were conducted using acclimation culture technique
in medium broth containing D-phenylalanine amide as a sole source of nitrogen. Bacteria capable of growing
at 30ºC and 45ºC were screened and isolated. Twenty-one and seventeen soil samples showed the hydrolysis
of D-phenylalanine amide to D-phenylalanine determined by thin layer chromatography and forty-seven and
thirty-four strains were isolated at 30ºC and 45ºC, respectively. Each isolate obtained was screened for its
ability to degrade D-phenylalanine amide. Thirteen of forty-seven strains and nineteen of thirty-four strains
isolated at 30ºC and 45ºC, respectively exhibited D-phenylalanine amide degradation. However, only isolate
BS16 exhibited degradation toward D-tert-leucine. The enzyme activity toward D-phenylalanine amide was detected from the bacterial cells, but not in
supernatant indicating that the amidase was an intracellular enzyme. The bacterial cells grown in the broth
with and without D-amino acid amide showed enzyme activity leading to the conclusion that it was constitutive enzyme.