established in liquid one-tenthstrength
NSY medium (0.3 g l21
) with and without
0.5 g l21 test substance. OD differences of ,10 %, of 10–
50 % and of .50 % of the OD established on the medium
without the test substance were scored after 10 days of
growth as no utilization (2), weak utilization (W) and
good utilization (+), respectively.