Asian Science
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Abstract: Four strains of Pycnoporus sanguineus isolated
from Shah Alam (KUM 60954), Endau Rompin (KUM 60955), Cherating (KUM 60956),
Gombak (KUM 60957) and the standard strain from Thailand (KUM 60953) were
evaluated for their ability to grow on Polycyclic Aromatic Hydrocarbon
(PAH)- and acetonitrile-incorporated Potato Dextrose Agar (PDA). The mycelial
growth was then compared to the growth of P. sanguineus on PAH
and acetonitrile free PDA. All strains tested showed a high tolerance
to PAH up to 25 ppm and 2.5% of acetonitrile. Laccase derived from the
best strains KUM 60954 and KUM 60953 which exhibited higher tolerance
to both PAH and acetonitrile was further characterised. The activity was
maximum for both strains at pH 5.0 and 40 °C. Laccase from both strains
was stable over a wide range of pH (3-5) and at temperatures below 60 °C.
Laccase was stored as a concentrate or as a lyophilised powder to minimise
the degradation of enzyme activity during storage. The laccase activity
in the extract remained a high activity up to four months at optimum pH
5.0 and at both 0 and 4 °C. Further laccase was also stable up to 24
h at 40 °C when mixed with 1% of acetonitrile.